A Search for Intrinsic HI 21 cm and OH 18 cm Absorption Toward Compact Radio Sources
Kathryn Grasha Jeremy Darling Alberto Bolatto Adam K. Leroy John T. Stocke

    


1Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia; kathryn.grasha@anu.edu.au
2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia
3Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA
4Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA
5Department of Astronomy, The Ohio State University, McPherson Laboratory, 140 West 18th Avenue, Columbus, OH 43210-1173, USA




We present the results of a large search for intrinsic HI 21 cm and OH
18 cm absorption in 145 compact radio sources in the redshift range 0.02<
z <3.8 with the Green Bank Telescope. We re-detect HI 21 cm 
absorption toward six known absorption systems but detect no new HI or OH
absorption in 102 interference-free sources.  
79 sources have not previously been observed for HI 21 cm
absorption. We recover a mean optical depth limit of
τ_3σ<0.023 for all the non-detections in the survey.  
Our results do not support
the high intrinsic absorption rates found by previous studies in compact
radio sources at low redshift. Our results do, however, support the hypothesis
proposed by Curran  (2008) that high ultraviolet (UV) 
luminosity active galactic nuclei (AGN) do not show intrinsic HI 21 cm
absorption, confirming a threshold of L_ UV =
10^23 W Hz^-1, above which our intrinsic absorption fraction is zero
(54 sources). The exact nature of the UV luminosity effect on HI absorption systems remains ambiguous. We additionally find no statistical correlation between the 1.4 GHz radio luminosity or the source size and the 21 cm absorption detection rate. 
We attribute the lack of intrinsic absorption in our survey to the UV luminosity effect
caused by an optical selection bias and a decreased column density
sensitivity with increasing redshift due to lower radio continuum flux
densities, high radio frequency interference, and higher telescope system temperatures at low frequencies.  

 





§ INTRODUCTION

Many compact radio sources are likely to be young and/or confined radio jets. It is likely that these very young and emerging jets are still contained within their host galaxy, potentially providing favorable sites to observe the interactions between the young, compact jets and the intrinsic gaseous interstellar medium (ISM) near the central active galactic nuclei (AGN) within their galaxies <cit.>. 

One of the best observational tracers of the intrinsic ISM is with observations of the cold neutral medium (CNM) as traced by the hyperfine spin-flip transition of neutral hydrogen, the HI 21 cm line. When cold neutral hydrogen (T ∼ 100 K) is present, absorption of the 21 cm line against these compact radio sources gives the ability to detect neutral hydrogen absorption systems at any redshift. The 21 cm absorption line could thus be an invaluable probe of the kinematics and morphology of the neutral gas in the nuclear regions of galaxies.  Studies of HI quite often employ the use of compact radio sources as the best targets to detect 21 cm absorbers as the jets are still contained within their host galaxies, providing insight to the possible feedback interactions of these young jets with the neutral ambient medium.

Since the seminal work of <cit.> that identified extragalactic associated HI 21 cm absorption in NGC 5128, a large number of HI 21 cm absorption studies have been carried out in an attempt to provide a better understanding of the properties of neutral gas, especially within compact radio source host galaxies. The discovery of blueshifted HI absorption systems at large velocities <cit.> with respect to the systemic optical redshift of the galaxy hosting the compact radio source is indicative of jet-driven outflows of neutral gas. This signifies a unique avenue in which to study the fueling of the AGN as well as the effects of AGN feedback and its interaction with the environment and gas kinematics of the host galaxy.

The majority of HI 21 cm absorption systems have high column density and are damped Lyα (DLA; N_ HI≥ 2× 10^20 cm^-2) systems. 
The vast majority of 21 cm absorption systems have low redshifts, z≲1 <cit.> but some of intrinsic absorbers do lie above z≳1 <cit.>. 
Previous surveys have identified a few commonalities exhibited in intrinsic HI 21 cm absorbers:  

(1) High detection rates, of order 30-50%, are found in surveys of 
compact radio sources at redshift z≲1 <cit.> whereas the detection rates in higher
redshift surveys are significantly lower <cit.>. 
The deficiency of HI 21 cm absorbers at high redshift could arise from detection biases in sample selection or could signify physical changes in the reservoirs of cold neutral gas, AGN activity, or radio emission at earlier cosmic time  <cit.>. 

(2) No intrinsic 21 cm absorption system has ever been detected toward objects with an ultraviolet (UV) luminosity 
L_ UV > 10^23 W Hz^-1 <cit.> at any redshift. This luminosity is indicative of a UV bright, unobscured quasar with minimal extinction along the line of sight. 
While the exact nature of the UV luminosity's effect on neutral gas 
remains somewhat ambiguous, the observed threshold likely represents an analogue to the AGN 
“proximity effect” seen in UV absorption line studies <cit.>. The effect on the HI 21 cm absorption line 
could be the result of ionization of gas from the UV radiation <cit.>, an increase in the spin temperature of the cold neutral medium <cit.>, effectively decreasing the observed line optical depth for a given column density, or simply identifying systems that are unextincted and have little gas and dust along the line of sight.  

(3) High redshift, optically bright AGN are most likely to have spectroscopic redshifts. 
Most radio sources with spectroscopic redshifts beyond z∼1.2 have UV luminosities in excess of L_ UV>10^23 W Hz^-1. 
The UV luminosity threshold effect is therefore especially
problematic for high redshift 21 cm absorption line detection because optical spectroscopic redshifts of AGN rely on 
rest-frame UV emission lines, biasing target selection toward the brightest UV sources that have never been detected in 21 cm absorption. 

Another gas tracer that may be associated with neutral hydrogen absorption is the hydroxyl molecule (OH). OH shows absorption, emission, and maser activity in four hyperfine and lambda-doubled transitions at 18 cm. Cospatial HI and OH lines allow one to constrain the cosmic evolution of several physical constants: the electron-proton mass ratio μ≡ m_p/m_e, the fine structure constant α = e^2/ħ c, and the proton g-factor g_p
<cit.>. The fine structure constant α parametrizes the strength of electromagnetic interactions, and some quasar studies suggest a decrease in α in the early universe <cit.>. Changes in the physical constants over cosmic time will cause spectral lines to shift from their relative measured values at present-day and have implications for physics and cosmology. 

Redshifted OH systems are rarer than HI 21 cm absorption systems and are always found in systems that are detected in 21 cm absorption as well. Five OH 18 cm absorption line systems are known to date at
z>0.2 <cit.>, and none lie beyond z=1. 
Compact radio sources still confined within the host galaxy are the perfect environment to search for molecular systems, producing optimal conditions to observed OH absorption lines, especially the conjugate[The satellite OH conjugate lines (1612 and 1720 MHz) are a rare astrophysical phenomenon where the two lines have the same shape but opposite signs, arising due a population anti-inversion mechanism resulting from quantum mechanical selection rules <cit.>.] OH lines, systems in which OH gas complexes become sources of coupled weak maser emission and non-thermal absorption. Large surveys over a broad redshift range are required to detect the rare coincidence of HI 21 cm and OH 18 cm absorption lines.

In this paper, we perform a large survey for intrinsic HI 21 cm and OH 18 cm
absorption in the host galaxies of 145 compact radio sources, including
GHz-Peaked Spectrum (GPS), Compact Steep-Spectrum (CSS), Compact Symmetric Objects (CSOs), and Flat-Spectrum Radio Sources (FSRSs; see Section <ref> for further discussion of these classifications), using the Green Bank Telescope[The
  National Radio Astronomy Observatory is a facility of the National
  Science Foundation operated under cooperative agreement by Associated
  Universities, Inc.] (GBT) selected across the redshift range (0.02< z <3.8) in an attempt to increase the number of known absorbers, especially at high redshift. In addition to the results of our search
for intrinsic HI and OH absorption, we examine several biases that influence
the detection of intrinsic absorption, including redshift selection, UV
luminosity, radio luminosity, radio source size, covering factor, and spin
temperature. We explore the possibility that the nature of our
high redshift selection of radio sources biases the results against
detection of intrinsic 21 cm absorption. Previous 21 cm absorption studies of the same
biases we investigate here were performed on a heterogeneous compilation of
previous known intrinsic HI absorption with a wide range of source sizes that were typically located at low redshift <cit.>. These results are arguably not unbiased because non-detections have generally not been uniformly published, which will skew the detection rates. We use this large survey to test the UV luminosity threshold hypothesis and the high rate of intrinsic HI 21 cm absorption toward compact radio sources. 

The paper is outlined as follows. The compact radio source sample selection is described in Section <ref> and their observations are described in Section <ref>. The
results and comparison to previous 21 cm absorption searches are presented in
Section <ref>. Section <ref> presents the
analysis of the HI detection rate with the
radio and UV luminosities. We discuss the findings in Section <ref> and we summarize the results and conclusions in Section <ref>.   

Throughout this paper, we adopt a flat ΛCDM cosmology
with Ω_ m = 0.27, Ω_Λ =0.73, and H_∘ =
71  Mpc^-1 <cit.>.  All quantities obtained from the
literature are recalculated (if necessary) for this cosmology. 





§ SAMPLE SELECTION

Compact radio sources are often classified by their morphology and radio spectral index, providing insight into the properties and nature of these sources. GHz-Peaked Spectrum (GPS) sources are intrinsically small <cit.> and show a low frequency turn-over in their spectra, mainly attributed to synchrotron self-absorption and free-free (thermal bremsstrahlung) absorption <cit.>. Compact Steep-Spectrum (CSS) sources show steeper power-law spectra than is typically seen in radio galaxies <cit.>. Compact Symmetric Objects (CSOs) show a compact double-lobed structure with advance speeds, indicative of young jets <cit.>. Flat-Spectrum Radio Sources (FSRSs) are characterized with a double-peaked synchrotron/Compton spectral energy distribution, possibly associated with a blazar or with the compact core of a radio galaxy <cit.>. These classifications are not disjoint in the literature; for example, most CSOs are also classified as GPS sources <cit.>.  

Candidate intrinsic HI 21 cm absorbers in this survey include nearly all known GPS sources, CSS sources, and CSOs (ca. 2005) with δ>-35^∘ <cit.> for a total of 60 objects (34 GPS sources, 29 CSS sources, and 7 CSOs, with some overlap between the classifications). The FSRSs were selected from <cit.> with S>0.3 Jy at 780 MHz, adding an additional 85 sources to the sample selection.  

In total, the sample includes 145 objects with known optical redshifts 0 < z < 4, with the vast majority of the sample at redshifts less than z∼1. Figure <ref> shows the redshift and the continuum flux 
  density at the expected redshifted line frequency of the two samples (compact and flat-spectrum sources; Section <ref>).   
Table <ref>
lists the sources, their radio
classifications (GPS, CSS, CSO, and FSRS), total integration time for each reduced spectrum.  





§ OBSERVATIONS AND DATA REDUCTION

From September 2004 to August 2005, we observed 85 FSRSs for intrinsic absorption in the HI 21 cm 
line (1420.405752 MHz), 
and 81 in the four 18 cm OH lines at
1612.231, 1665.4018, 1667.35903, and 1720.5300 MHz simultaneously (GBT program 04C–018). 
We additionally observed 60 GPS, CSS, and CSO radio sources for intrinsic 
absorption from December 2005 to May 2006 (GBT program 06A–044): 
 59 sources were observed in the HI 21 cm line,
and 44 sources were observed in the four OH 18 cm lines. One source,
PKS 2135-209, was only observed in the OH lines.  
All observations were conducted 
using a 5-minute position-switched mode in two linear polarizations with
9-level sampling, 3- to 15-sec records, and a 50 MHz bandwidth
centered at the redshift of the radio source host galaxy.  
Each bandwidth contains 4096 spectral channels with a width of 12.2 kHz per channel (a channel width of 3.86  at z=0.5).  
A calibration diode signal was injected for half of each record. Total
on-source integration times were typically 30 minutes for the GPS, CSS, and
CSO sources and 5 minutes for the FSRSs, listed in Table <ref>. 

Each off-source-flattened and diode-calibrated spectral record was inspected
and flagged for radio frequency interference (RFI).  All records were then
averaged in time and polarization, Hanning smoothed, and 
baseline-flattened using a polynomial fit, typically of third
order with a final post-smoothing spectral resolution of 24.4 kHz per channel.  
All data reduction was performed using
GBTIDL[GBTIDL (<http://gbtidl.nrao.edu/>) is the data
  reduction package produced by NRAO and written in the IDL language for
  the reduction of GBT data.].  
Final mean spectra were inspected for absorption lines within a few thousand km s^-1 
of the optical redshift of the host galaxy. The observable velocity span was typically determined by the RFI
conditions rather than the spectral bandwidth.





§ RESULTS
 
The nature of 36 sources (25% of the total sample) remains ambiguous due to unrecoverable contamination of RFI, a pernicious impediment to the detection of new absorption systems. The remaining 108 sources have the majority of their spectral range free from RFI and are able to be searched for HI or OH absorption. 

Table <ref> lists the RFI-free velocity range searched
for HI 21 cm absorption toward each radio source, the measured rms noise (away
from RFI and spectral lines)
in the mean spectra, the continuum flux density at the expected
frequency of the redshifted spectral line obtained from power-law
fits to extant continuum measurements in the literature (see Section <ref>), HI column densities (or upper limits toward radio sources
not detected in 21 cm absorption), and the projected size of
each radio source as obtained from literature searches (see Section <ref>).  

Table <ref> lists the properties of the OH 18 cm line observations toward a subset of the
sample.  The 1665 and 1667 MHz lines are both observed, but we only list the
properties of the 1667 MHz line because it places the strongest upper limit
on the OH column density among the 18 cm lines.  The continuum
flux density is interpolated at the expected frequency of the redshifted 1667 MHz line
from continuum measurements in the literature following the same method used for the 
21 cm spectral observations (Section <ref>). When the 1667 MHz line could not be 
observed due to RFI, the 1612 or 1720 MHz transitions are used 
as the reference instead.  





 §.§ Line Detections and Limits

We detect intrinsic HI 21 cm absorption in 6 of the 108 RFI-free
compact radio sources in our sample. The detection 
rate is 5.6%, substantially lower than 
in previous intrinsic HI absorption line surveys (Section <ref>).
All of these absorption lines are detected in previous surveys (see Table <ref> for references).
The detected line spectra are shown in Figure <ref>,
where velocities are referenced to the optical heliocentric redshift. Table <ref> lists the measured and derived properties of the detected HI 21 cm absorption lines.

Table <ref> lists the measured upper limits to the column densities, calculated according to Section <ref> and further discussed in light of previous studies in Section <ref>. We show the spectra of the 102 RFI-free sources that show no significant HI 21 cm absorption lines and are predominately free from RFI in the Appendix. 

PKS 0742+10, at z=2.64, shows a redshifted negative spectral feature with a signal to noise of 3.4σ.  
We compare our spectrum to that of <cit.>, also obtained at the GBT. The <cit.> spectrum 
shows narrow RFI at the frequency of the potential absorption line. This suggests
that the feature in our spectrum is likely to be an incompletely flagged or low-level RFI feature.
We therefore treat PKS 0742+10 as a non-detection in all subsequent figures and statistics, with the rms noise measured away from the spectral feature.  

None of the four 18 cm OH lines are detected in absorption or emission 
in 102 RFI-free spectra out of the 125 objects observed.  
Table <ref> lists the properties of the OH sample, and 
Figure <ref> in the Appendix shows the OH 1667 MHz  non-detection spectra of the four
21 cm absorbers in our sample with RFI-free OH spectral observations.





 §.§ Flux Densities

The nature of our observations with the GBT maximizes the on-time observation of targets and as a result does not give the necessary observations to flux calibrate the data and directly measure the continuum flux density. Moreover, for position-switched observations, RFI and instrumental effects frequently result in negative continuum values, artificial continuum slopes, and bandpass structure. 
The continuum is however paramount to obtain the optical depth and measure the column density or place a limit in the cases of non-detections (see eqn. <ref>). We therefore obtain the continuum flux density at the frequency of the redshifted HI and OH
line of each source from an interpolation between
extant continuum measurements in the NASA Extragalactic Database (NED)
using a single spectral index power-law fit (a linear fit in
log S_ν–log ν space). In order to cope with the heterogeneous
literature continuum measurements, we try whenever possible to select
values published from the same catalogs and pass bands, most often
observations at 1410, 1340, 750, 635, 408, and 365 MHz
<cit.>.
The uncertainties in the interpolated 
continuum flux densities listed in Tables <ref> and <ref> are obtained from estimates of the
1σ confidence intervals of the power law continuum fits for each object. This treatment neglects
potentially significant time variation in radio source fluxes.





 §.§ Column Densities



  §.§.§ HI Column Density

Column densities are derived from the
integrated optical depths of spectral lines. The column density associated with a given 21-cm line optical depth is calculated according to <cit.> as
	
    N_ HI = (1.8 × 10^18  cm^2)  T_s/f∫τ dv,

where T_s is the spin temperature of the 21 cm line in Kelvin, f is the
fraction of the area of the continuum source covered by the absorber, and
∫τ dv is the optical depth τ integrated across the velocity 
span of the line, in , calculated from the continuum fluxes acquired in Section <ref> and the strength of the absorption line.  
A Gaussian absorption profile can be integrated:
∫τ dv = √(π/ln 2) τ_ max Δ v/2, where 
τ_ max is the peak optical depth of a line with a full width half max (FWHM) of Δ v. The column densities of the six re-detections of 21 cm absorption are calculated according to Eq. <ref> and are listed in Table <ref>. We use both Gaussian fits and direct integration for the total HI column density of the 21 cm detections.
 
For the non-detections, we assume optically thin lines, and the 3σ upper limit on the 
column density can be approximated by 
	
    N _HI, 3σ < (1.9× 10^18 cm^-2) T_s/f τ_3σ Δ v  ,

where τ_3σ≈ 3σ/S, σ is the rms noise, and 
S is the continuum flux density of the radio source at the redshifted line frequency.

All HI column densities are computed assuming T_s = 100 K and a uniform covering factor of f = 1, resulting in an HI column density limit in the CNM phase of the ISM. We note that this is not the total HI column density as the 21 cm transition is not a reliable tracer of the gas in WNM due to the optical depth inversely related to the spin temperature. 

Non-detection column density limits assume Δ v=30 . Table <ref> 
lists the column densities and limits for the non-detections and all upper limit spectra are shown in the Appendix.  
Figure <ref> shows the HI column density distribution as a function of redshift
for the 108 RFI-free sources. 





  §.§.§ OH Column Density

For the redshifted OH 18 cm line non-detections, we use
the 1667 MHz OH transition to place the strongest upper limit on the
OH column densities via
	
    N _OH, 3σ < X × 1.0645  T_x/f τ_3σ Δ v ,

where X = 2.38 × 10^14 cm^-2 <cit.> for the 1667 MHz transition,
and T_x is the excitation temperature of the OH 1667 MHz line.
When the 1667 MHz line could not be observed due to RFI, the OH column
density limit is calculated using the 1612 MHz or 1720 MHz transition, which have
X = 2.14 × 10^15 cm^-2 (X_1612 MHz = 9 × X_1667  MHz, following the 
18 cm OH line ratios in thermodynamic equilibrium).  We make no assumption about the OH
line excitation temperatures and leave T_x as a free parameter in our tabulation and analysis.  
As with the HI lines, for the OH lines we assume a uniform covering factor of f = 1, and a
line width of Δ v=30 .  
Figure <ref> shows the OH
column density limits as a function of redshift for the 102 RFI-free sources in the sample.

Because we find no OH detections, as well as no new HI detections, we are unable to place any meaningful constraint on possible redshift variations in the fundamental physical constants, discussed in Section <ref>. 





 §.§ Comparison to Previous Work




  §.§.§ HI 21 cm Absorption Studies

This intrinsic HI 21 cm absorption search toward 144 compact radio
sources (Table <ref>; one additional source is only observed for the four OH lines, for a total sample size of 145) obtained 108 spectra including 
six re-detections, with 36 sources remaining ambiguous due to RFI.  
21 objects in the survey sample are previously observed for intrinsic HI absorption
including nine known 21 cm line absorbers in the sample. 

We made no
new 21 cm absorption detections, however, we do re-detect six of the nine known HI absorption
systems (Table <ref>). We are not able to re-detect the three
absorption line systems toward 3C49, B3 1355+441 <cit.> or 3C190
<cit.> due to RFI. 


Our spectra of 3C138, 3C147, 0239+108, OE+131, TXS 0902+490, HB89 0954+658, 1004+141, FBQS J1159+2914, 1418+546, 1642+690, 3C380, 4C+29.56, 2007+222, and
PKS 2149+056 improves the previous upper limit measurements <cit.>.
Three objects, B3 0248+430, SBS 0804+499, and 3C147, were impacted by RFI in our observations, preventing 
independent upper limits on previous measurements.  
Five sources, 3C138, HB89 0754+100, COINSJ 1546+0026, PKS 2121-01, and HB89 2342+821 have
column density limits comparable to previous surveys. Only two limits on our sources, B2 0738+31 and COINS
J2022+6136, did not improve on previously published column density limits. 
The remaining 79 sources have (to our knowledge) never been searched for intrinsic HI absorption
before. Table <ref> lists the column densities or column density limits from our survey and
previous surveys along with references, if applicable. All non-detections quoted at the 3σ level use the assumptions listed in Section <ref>. 

The six detected absorbers all have column densities near or greater than the DLA limit of N_ HI>2×10^20 cm^-2 and we reached adequate sensitivity to have detected most known redshifted 21 cm absorbers if they had been present in our sample. 70% of our non-detections have 3σ upper limits below the DLA column density threshold for the detected absorbers. This suggests that while we have the sensitivity to detect new systems of cold gas (T∼100 K) at sub-DLA column densities, there must be physical reasons for the dearth of absorption lines in these redshifts radio sources in this survey, which we investigate further in Section <ref>. 





  §.§.§ OH 18 cm Absorption Studies

We searched 125 radio sources for the four OH 18 cm
lines, which can appear in either emission or absorption.
The spectra of 102 objects are unaffected by RFI for at least one of the four OH
transitions.  
No OH emission or absorption lines are detected in any of the RFI-free spectra and the OH column density upper limits are reported in Table <ref>. Only one source in our sample, B3 1355+441, has prior OH observations <cit.>. We report a 3σ upper limit on the OH column density of N_ OH/T_x <2.1×10^13 cm^-2 K^-1, an improvement over of the 3σ measurement of N_ OH/T_x < 11×10^13 cm^-2 K^-1 from <cit.>.

Four RFI-free OH observations toward known 21 cm absorbers (Figure <ref>) do not detect any OH lines despite reaching very low optical depths, 
0.002 < τ_3σ < 0.01 (Table <ref>).  
OH column density upper limits for the full sample span the range 
10^12 cm^-2 K^-1<N_ OH/T_x < 10^16 cm^-2 K^-1, 
consistent with upper limits quoted
in previous surveys for non-detections of OH 18 cm absorption <cit.>.





§ ANALYSIS

We detect no new 21 cm absorption systems in our survey. We do, however, re-detect six known absorbers, for a detection rate of 5.6%. The following sections discuss factors that may negatively impact the ability to detect neutral HI gas, especially at high-redshift.





 §.§ Radio Continuum Luminosity

One possible explanation of our low detection rate, especially at
high redshift, is a high spin temperature. As shown in Equation <ref>,
the measured HI column density is proportional to the (unknown) spin temperature T_s of
the absorbing gas.  
Previous studies investigated the impact of the local radio radiation field in driving the spin temperature up in associated absorption systems <cit.>, finding little to no significance dependence of the radio luminosity on the detection rate or N_ HI. If the spin temperature is coupled to the local radio radiation temperature, an increase would cause weaker line absorption for a given column density. However, recent work by <cit.> suggest that gas excitation from the radio continuum may be responsible for the dearth of 21-cm absorbers detected at high redshift. This suggests that the spin temperature of the gas, a measure of the excitation from the lower hyperfine level <cit.>, can be raised by excitation to the upper hyperfine level by rest-frame 1420 MHz photons. <cit.> has shown that this is unlikely and that the photoionization from the UV luminosity is dominant factor over the radio luminosity in negatively impacting the detection rate of 21 cm absorbers (see Section <ref>). 

We test this possibility of the impact of the incident 21 cm luminosity on the absorption detection rate by 
calculating the specific radio continuum luminosity in the vicinity of the 21 cm line in the rest frame of
each host galaxy <cit.>:
	
    L_ν = 4π  D_ L^2  S_ν/1+z W Hz^-1,

where D_ L is the luminosity distance of the host galaxy, S_ν is the observed
21 cm flux density at the frequency of the redshifted 21 cm observations,
as calculated in Section <ref> and listed in Table <ref>, and
z is the redshift.  

Table <ref> lists the radio continuum luminosities for the sample.
The median radio continuum luminosity of the detections is log (L_
  Radio/ W Hz^-1) = 27.5±0.4, consistent with the median luminosity for the
non-detections at 27.5±0.7.  
A Kolmogorov-Smirnov Test (KS-test) shows that the 21 cm rest-frame luminosity differs between the detections and non-detections at less than 1σ confidence level; the 21 cm luminosity does not appear to be a major factor in 21 cm absorption and cannot explain our low detection rate, also found in <cit.>.  

With the exception of a few low-luminosity radio sources, the radio
luminosity-redshift distribution shows the Malmquist bias
for flux-limited surveys: the most luminous objects lie at the 
largest distances (Figure <ref>). 
As expected, the detections show an inverse correlation of radio luminosity with column density (Figure <ref>). This, however, is an observational bias because the highest flux
density sources typically have the highest luminosities (Figure <ref>), and
high flux densities provide greater column density sensitivity.





 §.§ Ultraviolet Luminosity

Another possible explanation for this survey's lack of intrinsic 21 cm absorption at high redshift
is the hypothesis proposed by <cit.> that AGN with a high ultraviolet (λ_ UV = 1216 Å) luminosity (L_  UV>10^23 W Hz^-1) may inhibit 21 cm absorption. If the UV flux of the central AGN is sufficient to ionize (or simply heat) the neutral gas within the host galaxy, UV-bright galaxies will be biased against the detection of 21 cm absorbers. These UV bright sources are also likely to be unextincted and may simply have less gas and dust along the line of sight compared to extincted sources, lowering the ability to detect absorption systems as sensitivity depends on both the covering fraction of the gas against the background source and the spin temperature of the gas. The UV luminosity bias will be compounded with increasing redshift because flux-limited surveys will naturally select UV-luminous objects at all redshifts.

We have searched the literature for optical and near-IR photometry of each
source in our sample to estimate the rest-frame UV luminosity following the method in <cit.>.  
Table <ref> lists the optical and near-IR magnitudes for the sources searched for 21 cm absorption.
Of our detected absorbers, 4C+76.03 does not have adequate available optical or near-IR observations. For this source, along with six sources with non-detections, we are unable to estimate the UV-optical slope in order to measure the expected UV luminosity. We therefore do not calculate a UV luminosity for these sources and they have been excluded from all plots and analysis related to the UV luminosity. In conclusion, we have five detections in 21 cm absorption and 96 sources with upper limits that we are able to calculate a UV luminosity for in order to test the hypothesis proposed by <cit.> for the ionization of the atomic gas in UV-bright radio sources. 

Using visible band
magnitudes and attempting to maintain consistency in the heterogeneous 
sample and sources of magnitudes, the extrapolation or  
interpolation of the rest-frame UV luminosity at 1216 Å is 
performed using a power-law fit to the B and R bands as these two bands are readily available for most for the sample.  
For sources where either of those bands are not available, observations at V or K bands are 
substituted in that order. We require a minimum of two bands to perform the power-law fit, for galaxies with more than two available magnitudes, we use all available optical and near-IR bands. Objects with Sloan Digital Sky Survey
(SDSS) u'g'r'i'z' magnitudes are converted to Johnson 
magnitudes using the methods described in <cit.> and are not corrected for intrinsic source extinction.
  
The fitting is done by converting the visible
band magnitudes to fluxes using Vega as a zero-point reference, with values
for Vega in each band taken from <cit.>, <cit.>, and
<cit.>. Under the assumption that a single power law applies from the observed optical wavelengths down to 1216 Å, the UV flux density in the rest-frame of the host galaxy is obtained from the 
observed flux F_1 at wavelength λ_1 from <cit.> as,
	
    F_λ_ UV(1+z) = F_1  [ λ_ UV    (1+z)/λ_1]^α,

where the spectral index α is estimated as α =
log(F_2/F_1)/log(λ_2/λ_1) for two observations at
bands λ_1 and λ_2, with fluxes F_1 and F_2.  This allows us to extrapolate from the observed visible-band photometry to obtain a UV flux at the observed wavelength λ_ UV(1+z). 
The specific UV luminosity in the rest-frame of the host galaxy is then calculated as,
	
    L_λ_ UV = 4π D_ L^2  F_λ_
          UV(1+z)/1+z W Hz^-1,

where D_ L is the luminosity distance to the host galaxy and F_λ_ UV(1+z) is the rest-frame UV flux calculated from Eq. <ref>. 


The median and 1σ values of the UV luminosity of the full sample of 101 sources (5 detections, 96 non-detections, 7 sources with no L_ UV measurement)
is log(L_ UV/ W Hz^-1) = 23.1 ± 1.4, consistent with the UV luminosity threshold of 10^23 W Hz^-1. The median luminosity of the HI absorption detections is 
log (L_ UV/ W Hz^-1) = 20.5±1.1, and the median luminosity of the 
non-detections is log (L_ UV/ W Hz^-1) = 23.2±1.4. If we only consider systems below the L_ UV < 10^23 W Hz^-1 threshold, this reduces the number of RFI-free sources searched for 21 cm absorption from 101 to 47 targets. The detection rate for this subset of UV-faint sources increases to 9.8%. 

Figure <ref> shows the distribution of the HI column density as a function UV luminosity. There are no HI 21 cm line absorbers associated with sources with UV luminosities above log (L_ UV/ W Hz^-1) > 23, further supporting the critical UV threshold above which 21 cm absorbers cannot be detected <cit.>.  Figure <ref> shows the UV luminosity as a function of redshift, demonstrating how the radio sources in this survey above a redshift of z∼1 predominately have UV luminosities that are above the threshold. The requirement of UV/optical spectroscopic redshifts for radio spectral line surveys typically cause the high redshift sources to be the most luminous and are not ideal targets to show 21 cm or molecular absorption. 

A KS-test comparing UV luminosities of the 21 cm detections to the non-detections, however, is not statistically significant, showing a 2.2σ difference between the samples. While the detections and non-detections do not appear to be drawn from distinct populations in UV luminosity, our sample of detections may simply be too small for statistical significance. 

Figure <ref> shows the radio versus UV luminosities of the 
sample with a Pearson correlation coefficient of r=0.35, significant at the 3.7σ level.  
As with all luminosity-luminosity plots of flux-limited samples, some degree of correlation 
can arise from the correlation of both luminosities with distance.
Figure <ref> shows the measured column density (or 3σ upper limits) versus
the ratio of the radio-to-UV luminosity.  
The five HI 21 cm absorbers have a weak preference be located in objects that have a higher than median ratio, indicating their preference to reside in sources with low UV luminosity and/or higher radio luminosity compared to the non-detected sources. A KS test results in a D-value of 0.677, significant at 3.2σ. Future work with a larger number of detections will be able to further investigate the effect of the UV and radio luminosities on cold gas, especially investigating preference for 21 cm absorption in UV-faint, radio-loud sources. 





 §.§ Physical Size

The size of the radio source may also influence the detection of
HI 21 cm absorption.  If the radio lobes predominately
reside outside of the host galaxy, then the HI covering fraction 
will be small, and the apparent 21 cm optical depth will be correspondingly 
diminished.

The sizes of the radio sources in our survey are compiled from existing literature (Table <ref>). Physical and projected sizes are calculated using the angular size distance for each redshift. Projection (and presumably relativistic beaming) can 
confuse analysis and interpretation because not all sources with small projected linear sizes are physically small and vice versa <cit.>.

Figure <ref> shows the HI column densities (upper limits
in the case of non-detections) as a function of the projected linear size of the
radio source. 
The detection of absorption systems does not seem to depend on source size and we find no correlation between the column density and the size of the source (Pearson correlation coefficient of -0.31). 
The detection rates among
the larger sources (> 1 kpc; 2 out of 21 sources) and the smaller sources
(< 1 kpc; 4 out of 87 sources) are consistent with each other. 

Figure <ref> shows that UV luminosity does not correlate with source size
(correlation coefficient of r=0.14, non-significant at 1.4σ). Among the detections, the larger sources do exhibit a higher UV luminosity (L_ UV>10^22.5 W Hz^-1) than the smaller sources
(L_ UV<10^21 W Hz^-1), but the correlation is not statistically significant for a sample of five detections. Among non-detections, smaller sources (≤1 kpc) show a median UV luminosity of log L_ UV = 23.0±1.3 W Hz^-1, consistent with that of the larger sources (> 1 kpc) with a median of  log L_ UV = 22.6±1.5 W Hz^-1. The median UV luminosities likewise do not differ among radio source classification types: the median UV luminosity of the GPS, CSS, and CSO sources is log L_ UV=  22.8±1.6 W Hz^-1, while for FSRSs, the median value is log L_ UV = 23.1±1.2 W Hz^-1. 

Figure <ref> shows the relation between the radio continuum flux density and 
linear size of the radio jets, where the smallest radio sources tend to also be the faintest. These properties are countervailing in terms of 
the HI 21 cm absorption line detectability. Column density sensitivity
increases toward brighter objects, which tend to occur in the largest radio sources.  
However, the largest radio sources are the most evolved (thus possibly residing in galaxies with less
neutral gas) and most likely have the smallest covering fraction if the radio lobes are located outside the galaxy, reducing sensitivity for systems with lower column densities. We do not find that smaller sources have a higher rate of detection in 21 cm absorption, instead, we find that the detected absorbers cover the full range of jet sizes available in the survey, concluding that the size of the radio source is not a main contributor against the detection of HI 21 cm absorption. 





§ DISCUSSION

Some of the first surveys toward compact radio sources revealed intrinsic HI 21 cm detection rates of 30-60% in low redshift radio galaxies <cit.>. 
These previous surveys measure typical optical depth limits of τ_3σ≲ 0.001 - 0.2 for non-detections. We recover a mean optical depth limit of τ_3σ < 0.023 for our non-detections with a broad range from 10^-6 < τ_3σ < 0.15, where 70% of the non-detections lie below the DLA column density threshold. For sources in our survey that were also present in previous studies, we typically achieve greater sensitivity and are able to improve prior upper limits. 

The high success rate of 21 cm absorbers in these low-z studies have triggered follow up surveys to target compact radio sources in attempt to increase the detection rate of 21 cm absorption systems. The high success rates of these low-redshift surveys are in stark contrast, however, with surveys aimed toward high redshift z≳1 targets, where the detection rate plummets to single digits <cit.>, hinting at a connection between the redshift of the source and the success of detecting 21 cm absorption lines. 
While our sources span the redshift range 0.2<z<3.8, 75% of our RFI-free sample lie at redshifts z<1 and we recover a detection rate of less than 6%, with all absorbers identified in prior surveys. Lack of new detections, especially at low redshift, while reaching the sensitivity to re-detect known absorbers, demonstrates that there have to be external physical factors at play that negatively impact the detection rate of neutral gas absorbers in our sample. 


It is becoming clear that absorption of cold, neutral gas within galaxies that host radio sources is a multifaceted problem, with many factors impacting the detection rate of HI 21 cm absorption, especially at high redshift. Different effects may influence each other and work together, such as the observed anti-correlation of the HI column densities with size of the radio source <cit.>. We do not recover the same correlation, although our data are not inconsistent with a decrease in the HI column density with increase in source size (Figure <ref>). Our results are limited by an extremely small number of detections. Surveys such as this one, even with such a large non-detection rate, across a range of parameters (e.g., redshift, column density, UV/radio luminosity, radio source size) marks an attempt to better test and constrain the multitude of factors that impact the gas reservoirs and will allow for a more comprehensive understanding of the physical, kinematic, and chemical properties of the neutral gas in the AGN environment. 

Our low detection rate does not allow us to disentangle high (or even low) redshift biases against detection of 21 cm absorption. It is now clear that targeting UV-bright quasars, a condition imposed to reliably constrain the redshift of the source using the rest-frame UV continuum, are not identifying targets with large enough reservoirs of cold, neutral gas detectable with large radio surveys such as this study. Future surveys should be designed to target highly extincted, obscured sources that are not bright in the UV. Such surveys can leverage the infrared capabilities from WFIRST or even JWST to serendipitously detect potential HI targets that are UV/optical faint but bright in the mid-IR <cit.>. The SKA and its pathfinders will undoubtedly inaugurate a new era in HI absorption surveys, owing to  large instantaneous bandwidth coverage and field of view. The improved sensitivity and spectral coverage achievable with the SKA will overcome observational biases introduced by the conventional requirement of an optical redshift, ushering in a future of true “blind” HI absorption surveys. 







§ CONCLUSIONS

We present the results of the largest survey to date to search for intrinsic HI 21 cm and OH 18 cm
absorption at redshifts between 0.02<z<3.8 in 145 radio sources with the Green Bank Telescope. Below we summarize the major findings of this study.



  * Despite having the sensitivity to re-detect six previous detections of associated HI 21 cm absorption
in our sample, we make no new detections of 21 cm absorption in the
108 sources for which we have RFI-free spectra. The overall HI 21 cm absorption detection rate is 5.6%, but no detections are made for z > 0.7. This is significantly lower than similar low redshift surveys. 


  * We place an
upper limit on the column density for all non-detections not
affected by RFI, reaching a mean optical depth of τ_3σ<0.023. 79 of the radio sources have never been observed for HI 21 cm before. Despite low flux density values at the frequency of our
redshifted 21 cm spectral observations, coupled with the significant
presence of RFI in our low-frequency spectral observations, we 
reached adequate sensitivity to detect nearly any damped Lyα system. 


  * We have searched 125 of our sources for intrinsic molecular OH 18 cm
absorption. We do not detect any of the
four OH lines in the 102 RFI-free sources for which we have usable OH data,
obtaining exclusively upper limits for all measured OH column densities. We do not detect OH toward five of the known 21 cm absorption systems for which we have spectra coverage. Lack of OH absorption in these systems is not a result of insensitive measurements and we place upper limits on the OH column that are consistent with previously detected OH absorption systems. 


  * We find no HI 21 cm absorption above an ultraviolet luminosity of L_ UV≳ 10^23 W Hz^-1. This supports the hypothesis that intrinsic 21 cm absorption cannot be detected in galaxies when the UV luminosity exceeds this UV luminosity threshold <cit.>. Lack of 21 cm absorption in UV bright sources is an effect due to either the ionization of the neutral gas, higher spin temperatures in the environment around these luminous AGN, or sources that simply do not have a sufficient column of cold, neutral HI along the line of sight. 


  * We do not find statistically significant evidence that the HI column density the of 21 cm systems in our sample depends on the radio jet size, UV luminosity, or radio (1.4 GHz) luminosity. We are limited, however, by small numbers. 


  * With the exception of a single source, all of our RFI-free sources beyond z∼1.2 arise in UV-luminous sources above the UV luminosity threshold of L_ UV = 10^23 W Hz^-1.
This suggests that a possible explanation that the dearth of intrinsic 21 cm absorption systems at high redshift is an selection bias favoring UV-luminous AGN. Requiring optical redshifts (rest-frame UV for z≳ 1.6)
imposes an optical bias and low-dust column, selecting the brightest,
least obscured, and UV-bright radio sources at all redshifts. Such sources create an environment where neutral gas cannot survive and as such, are not detectable in 21 cm absorption.































































We are grateful for the valuable comments on this work by an anonymous referee that improved the scientific outcome and quality of the paper.
The authors thank T. Yan and K. Willett for data reduction scripts.  
The authors thank the staff members at the Green Bank Telescope for their assistance and support.
This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.  
This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.
Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. The authors acknowledge the invaluable labor of the maintenance and clerical staff at their institutions, whose contributions make scientific discoveries a reality. 
KG acknowledges the staff at the University House for the supportive and collaborative writing environment.

Facilities:  GBT

Software: GBTIDL <cit.>






[Adelman-McCarthy (2008)]adelman08 Adelman-McCarthy, J. K., Agüeros, M. A., Allam, S. S.  2008, , 175, 297
[Aditya (2016)]aditya16 Aditya, J. N .H. S., Kanekar, N., & Kurapati, S. 2016, , 455, 5000
[Aditya (2017)]aditya17 Aditya, J. N .H. S., Kanekar, N., Prochaska, J. X.,  2017, , 465, 5011
[Aditya & Kanekar(2018a)]aditya18a Aditya, J. N. H. S. & Kanekar, N. 2018a, , 473, 59
[Aditya & Kanekar(2018b)]aditya18b Aditya, J. N. H. S. & Kanekar, N. 2018b, , 481, 1578
[Allen, Ward & Hyland(1982)]allen82 Allen, D. A., Ward, M. J., & Hyland, A. R. 1982, , 199, 969 
[Antonucci & Ulvestad(1985)]antonucci85 Antonucci, R. R. J., & Ulvestad, J. S. 1985, , 294, 158  
[Atlee & Gould(2007)]atlee07 Atlee, D. W. & Gould, A. 2007, , 664, 53 
[Augusto (2006)]augusto06 Augusto, P., Gonzalez-Serrano, J. I., Perez-Fournon, I., & Wilkinson, P. N. 2006, , 368, 1411  
[Bajtlik (1988)]baj88 Bajtlik, S., Duncan, R. C., Ostriker, J. P., 1988, , 327, 570  
[Bessell(1979)]bessell79 Bessell, M. S. 1979, , 91, 589
[Campins (1985)]campins85 Campins, H., Rieke, G. H., & Lebofsky, M. J. 1985, , 90, 896
[Carballo (1999)]carballo99 Carballo, R., González-Serrano, J. I, Benn, C. R., Sánchez, S. F., & Vigotti, M. 1999, , 306, 137
[Carilli (1998)]carilli98 Carilli, C. L., Menten, K. M., Reid, M. J., Rupen, M. P., & Yun, M. S. 1998, , 498, 175 
[Chen (2005)]chen05 Chen, P. S., Fu, H. W., & Gao, Y. F. 2005, NewA, 11, 27 
[Chengalur (1999)]chengalur99 Chengalur, J. N., de Bruyn, A. G., & Narasimha, D. 1999, ASPC, 156, 228 
[Chengalur & Kanekar(2003)]chengalur03 Chengalur, J. N. & Kanekar, N. 2003, Phys. Rev. Lett., 91, 241302 
[Chun (2006)]chun06 Chun, M. R., Gharanfoli, S., Kulkarni, V. P., & Takamiya, M. 2006, , 131, 686
[Cody & Braun(2003)]cody03 Cody, A. M. & Braun, R. 2009, , 400, 871 
[Condon (1977)]condon77 Condon, J. J., Hicks, P. D, & Jauncey, D. L. 1977, , 82, 692 
[Condon (1998)]condon98 Condon, J. J., Cotton, W. D., Greisen, E. W., & Yin, Q. F. 1998, , 115, 1693 
[Cowie & Songaila(1995)]cowie95 Cowie, L. L. &  Songaila, A. 1995, , 453, 596
[Curran (2006)]curran06 Curran, S. J., Whiting, M. T., Murphy, M. T. 2006, , 371, 431
[Curran (2008)]curran08 Curran, S. J., Whiting, M. T., Wiklind, T., Webb, J. K, Murphy, M. T., & Purcell, C. R. 2008, , 391, 765  
[Curran & Whiting(2010)]cur10 Curran, S. J. & Whiting, M. T. 2010, , 712, 303 
[Curran(2010)]curran10 Curran, S. J. 2010, , 402, 2647
[Curran (2011)]curran11 Curran, S. J., Whiting, M. T., Murphy, M. T.,  2011, , 413, 1165
[Curran (2013)]curran13 Curran, S. J., Whiting, M. T., Sadler, E. M., & Bignell, C. 2013, , 428, 2053
[Curran (2016)]curran16 Curran, S. J., Duchesne, S. W., Divoli, A., & Allison, J. R. 2016, , 462, 4197
[Curran (2017)]curran17 Curran, S. J., Hunstead, R. W., Johnston, H. M.,  2017, , 470, 4600
[Curran(2018)]curran18 Curran, S. J. 2018, PASA, 35, 36
[Curran (2019)]curran19 Curran, S. J., Hunstead, R. W., Johnston, H. M.,  2019, , 484, 1182
[Darling(2003)]darling03 Darling, J. 2003, Phys. Rev. Lett., 91, 011301
[Darling(2004)]darling04 Darling, J. 2004, , 612, 58    
[de Vries, Barthel, & O'Dea(1997)]devries97 de Vries, W. H., Barthel, P. D., & O'Dea, C. P. 1997, , 321, 105 
[de Vries (1997b)]devries97b de Vries, W. H., O'Dea, C. P., Baum, S. A.,  1997b, , 110, 191
[de Vries (1998)]devries98 de Vries, W. H., O'Dea, C. P., Perlman, E., Baum, S. A., Lehnert, M. D., Stocke, J., Rector, T., & Elston, R. 1998, , 503, 138
[de Vries (2000)]devries00 de Vries, W. H., O'Dea, C. P., Barthel, P. D.,  2000, , 120, 2300 
[Douglas (1996)]douglas96 Douglas, J. N., Bash, F. N., & Bozyan, F. A. 1996, , 111, 1954 
[Drake (2004)]drake04 Drake, C. L., McGregor, P. J., & Dopita, M. A. 2004, , 128, 955 
[Drinkwater (1997)]drinkwater97 Drinkwater, M. J., Webster, R. L., Francis, P. J.,  1997, , 284, 85 
[Elitzur(1992)]elitzur92 Elitzur, M. 1992, Astronomical Masers (Dordrecht: Kluwer); http://adsabs.harvard.edu/abs/1992ASSL..170.....E
[Ellison, Hall, & Lira(2005)]ellison05 Ellison, S. L., Hall, P. B., & Lira, P. 2005, , 130, 1345
[Elvis (1994)]elvis94 Elvis, M., Wilkes, B. J., McDowell, J. C.,  1994, , 95, 1
[Fanti (1989)]fanti89 Fanti, C., Fanti, R., Parma, P.,  1989, , 217, 44
[Fanti (1990)]fanti90 Fanti, R., Fanti, C., Schilizzi, R. T.,  1990, , 231, 333 
[Fanti (2001)]fanti01 Fanti, C., Pozzi, F., Dallacasa, D.,  2001, , 369, 380  
[Fey & Charlot(1997)]fey97 Fey, A. L. & Charlot, P. 1997, , 111, 95 
[Fey & Charlot(2000)]fey00 Fey, A. L. & Charlot, P. 2000, , 128, 17 
[Ficarra, Grueff, & Tomassetti(1985)]ficarra85 Ficarra, A., Grueff, G., & Tomassetti, G. 1985, , 59, 255
[Field(1959)]field59 Field, G. B. 1959, , 129, 536
[Fiorucci, Ciprini, & Tosti(2004)]fiorucci04 Fiorucci, M., Ciprini, S., & Tosti, G. 2004, , 419, 25
[Fomalont (2000)]fomalont00 Fomalont, E. B., Frey, S., Paragi, Z.,  H. 2000, , 131, 95 
[Francis (2000)]francis00 Francis, P. J., Whiting, M. T., & Webster, R. L. 2000, , 17, 56 
[Fugmann(1988)]fugmann88 Fugmann, W. 1988, , 205, 86
[Gardner & Whiteoak(1978)]gardner78 Gardner, F. F. & Whiteoak, J. B. 1978, , 183, 711 
[Gelderman & Whittle(1994)]gelderman94 Gelderman, R. & Whittle, M., 1994, , 91, 491 
[Geréb (2014)]gereb14 Geréb, K., Morganti, R., & Oosterloo, T. A. 2014, , 569, A35
[Geréb (2015)]gereb15 Geréb, K., Maccagni, F. M., Morganti, R., & Oosterloo, T. A. 2015, , 575, 44
[Glass(1981)]glass81 Glass, I. S. 1981, , 194, 795
[Godwin (1977)]godwin77 Godwin, J. G. Bucknell, M. J., Dixon, K. L., Green, M. R., Peach, J. V., & Wallis, R. E. 1977, Obs, 97, 238 
[Gupta (2006)]gupta06 Gupta, N., Salter, C. J., Saikia, D. J., Ghosh, T., & Jeyakumar, S. 2006, , 373, 972 
[Gurvits (1999)]gurvits99 Gurvits, L. I.,  Kellermann, K. I.,  & Frey, S. 1999, , 342, 378 
[Hambly (2001)]hambly01 Hambly, N., MacGillivray, H. T., Read, M. A.,  2001, , 326, 1279 
[Healey (2007)]healey07 Healey, S. E., Romani, R. W., Taylor, G. B.,  2007, , 171, 61 
[Healey (2008)]healey08 Healey, S. E., Romani, R. W., Cotter, G.,  2008, , 175, 97 
[Hyland & Allen(1982)]hyland82 Hyland, A. R. & Allen, D. A. 1982, , 199, 943 
[Ishwara-Chandra (2003)]ishwara03 Ishwara-Chandra, C. H., Dwarakanath, K. S. & Anantharamaiah, K. R. 2003, JA&A, 24, 37 
[Jackson (2002)]jackson02 Jackson, C. A., Wall, J. V., Shaver, P. A., Kellermann, K. I., Hook, I. M., & Hawkins, M. R. S. 2002, , 386, 97 
[Jones (1974)]jones74 Jones, T. W., O'Dell, S. L., & Stein, W. A. 1974, , 192, 261 
[Jorgenson (2006)]jorgenson06 Jorgenson, R. A., Wolfe, A. M., Prochaska, J. X.,  2006, , 646, 730  
[Kanekar (2003)]kanekar03 Kanekar, N., Chengalur, J. N., de Bruyn, A. G., & Narasimha, D. 2003, , 345, 7 
[Kanekar & Chengalur(2003)]kanekarchengular03 Kanekar, N. & Chengalur, J. N. 2003, , 399, 857
[Kanekar & Chengalur(2004)]kanekar04 Kanekar, N. & Chengalur, J. N. 2004, , 350, 17
[Kanekar (2005)]kanekar05 Kanekar, N., Carilli, C. L., Langston, G. I.,  2005, Phys. Rev. Lett., 95, 261301 
[Kanekar (2006)]kanekar06 Kanekar, N., Subrahmanyan, R., Ellison, S. L.,  2006, , 370, L46
[Kanekar (2012)]kanekar12 Kanekar, N., Langston, G. I., Stocke, J. T., Carilli, C. L. & Menten, K. M. 2012, , 746, L16
[Kanekar (2014)]kanekar14a Kanekar, N., Prochaska, J. X., Smette, A.,  2014, , 438, 2131
[Kanekar (2018)]kanekar18 Kanekar, N., Ghosh, T., & Chengalur, J. N. 2018, Phys. Rev. Lett., 120, 061302
[Kellermann (1998)]kellermann98 Kellermann, K. I., Vermeulen, R. C., Zensus, J. A., & Cohen, M. H. 1998, , 115, 1295 
[Komatsu (2011)]komatsu11 Komatsu, E., Smith, K. M., Dunkley, J.,  2011, , 192, 18 
[Kotilainen (2005)]kotilainen05 Kotilainen, J. K., Hyvönen, T., & Falomo, R. 2005, , 440, 831    
[Kuhn(2004)]kuhn04 Kuhn, O. P. 2004, , 348, 647
[Labiano (2007)]labiano07 Labiano, A., Barthel, P. D., O'Dea, C. P., de Vries, W. H., Pérez, I., & Baum, S. A. 2007, , 463, 97   
[Laing & Peacock(1980)]laing80 Laing, R. A. & Peacock, J. A. 1980, , 190, 903 
[Large (1981)]large81 Large, M. I., Mills, B. Y., Little, A. G., Crawford, D. F., & Sutton, J. M. 1981, , 194, 693   
[Lister & Homan(2005)]lister05 Lister, M. L. & Homan, D. C. 2005, , 130, 1389 
[Maccagni (2017)]maccagni17 Maccagni, F. M., Morganti, R., Oosterloo, T. A., Geréb, K., & Maddox, N. 2017, , 604, A43
[Marganian (2006)]marganian06 Marganian, P., Garwood, R. W., Braatz, J. A., Radziwill, N. M., & Maddalena, R. J. 2006, ASPC, 351, 512
[Matthews & Sandage(1963)]matthews63 Matthews, T. A. & Sandage, A. R. 1963, , 138, 30
[McAlary (1983)]mcalary83 McAlary, C. W., McLaren, R. A., McGonegal, R. J. & Maza, J. 1983, , 52, 341 
[Menon(1983)]menon83 Menon, T. K. 1983, , 88, 598
[Molina (2012)]molina12 Molina, M., Landi, R., Bassini,  2012, , 548, 32
[Moore (1999)]moore99 Moore, C. B., Carilli, C. L., & Menten, K. M. 1999, , 510, L87
[Morganti, Killeen, & Tadhunter(1993)]morganti93 Morganti, R., Killeen, N. E. B., & Tadhunter, C. N., 1993, , 263, 1023
[Morganti (1997)]morganti97 Morganti, R., Oosterloo, T. A., Reynolds, J. E., & Tadhunter, C. N.  1997, , 284, 541
[Morganti (2001)]morganti01 Morganti, R., Oosterloo, T. A., Tadhunter, C. N., van Moorsel, G., Killeen, N., & Wills, K. A. 2001, , 323, 331 
[Moss (2017)]moss17 Moss, V. A., Allison, J. R., Sadler, E. M.,  2017, , 471, 2952
[Murphy (1993)]murphy93 Murphy, D. W., Browne, I. W. A., & Perley, R. A. 1993, , 264, 298  
[Murphy (2001)]murphy01 Murphy, M. T., Webb, J. K., Flambaum, V. V., 2001, , 327, 1208
[O'Dea (1991)]odea91 O'Dea, C. P., Baum, S. A., & Stanghellini, C. 1991, , 380, 660 
[O'Dea & Baum(1997)]odea97 O'Dea, C. P. & Baum, S. A. 1997, , 113, 148
[O'Dell (1978)]odell78 O'Dell, S. L., Puschell, J. J., Stein, W. A., & Warner, J. W. 1978, , 38, 267
[Odell (1978a)]odell78a Odell, S. L., Puschell, J. J., Stein, W. A.,  1978a, , 224, 22 
[Ojha (2009)]ojha09 Ojha, R., Zacharias, N., Hennessy, G. S., Gaume, R. A., & Johnston, K. J. 2009, , 138, 845
[Orienti (2007)]orienti07 Orienti, M., Dallacasa, D., & Stanghellini, C. 2007, , 475, 813
[Owsianik & Conway(1998)]owsianik98 Owsianki, I. & Conway, J. E. 1998, , 337, 69 
[Peacock & Wall(1982)]peacock82 Peacock, J. A. & Wall, J. V. 1982, , 198, 843 
[Peck & Taylor(2000)]peck00 Peck, A. B. & Taylor, G. B. 2000, , 534, 90 
[Petrov (2008)]petrov08 Petrov, L., Kovalev, Y. Y., Fomalont, E. B., & Gordon, D. 2008, , 136, 580 
[Pihlström (2003)]pih03 Pihlström, Y. M., Conway, J. E., & Vermeulen, R. C. 2003, , 404, 871
[Rahmani (2012)]rahmani12 Rahmani, H., Srianand, R., Gupta, N.,  2012, , 425, 556
[Ramírez (2004)]ramirez04 Ramírez, A., de Diego, J. A, Dultzin-Hacyan, D., & González-Pérez, J. N. 2004, , 421, 83 
[Rao (2006)]rao06 Rao, S. A., Turnshek, D. A, & Nestor, D. B. 2006, , 636, 610 
[Readhead (1996)]readhead96 Readhead, A. C. S, Taylor, G. B., Xu, W., Pearson, T. J., Wilkinson, P. N., & Polatidis, A. G. 1996, , 460, 612 
[Rengelink (1997)]renge97 Rengelink, R .B, Tang, Y., de Bruyn, A. G.,  1997, , 124, 259 
[Rhee (2018)]rhee18 Rhee, J., Lah, P., Briggs, F. H.,  2018, , 473, 1879
[Roberts(1970)]roberts70 Roberts, M. S, 1970, , 161, L9 
[Sandage(1965)]sandage65 Sandage, A. 1965, , 141, 1560
[Sandage (1965a)]sandage65a Sandage, A., Philippe, V., & Wyndham, J. D. 1965a, , 142, 1307 
[Sandage & Wyndham(1965b)]sandage65b Sandage, A. & Wyndham, J. D. 1965b, , 141, 328 
[Sbarufatti (2005)]sbarufatti05 Sbarufatti, B., Treves, A., Falomo, R., Heidt, J., Kotilainen, J., & Scarpa, R. 2005, , 129, 559
[Sbarufatti (2009)]sbarufatti09 Sbarufatti, B.. Ciprini, S., Kotilainen, J.,  2009, , 137, 337
[Schmitt & Kinney(1996)]schmitt96 Schmitt, H. R. & Kinney, A. L. 1996, , 463, 498
[Schneider (1983)]schneider83  Schneider, D. P., Gunn, J. E., & Hoessel, J. G. 1983, , 264, 337 
[Shen (1997)]shen97 Shen, Z. -Q., Wan, T. -S., Moran, J. M., Jauncey, D. L., Reynolds, J. E., & Tzioumis, A. K. 1997, , 114, 1999   
[Shen (1998)]shen98 Shen, Z. -Q., Wan, T. -S., Moran, J. M.,  1998, , 115, 1357 
[Simpson & Rawlings(2000)]simpson00 Simpson, C. & Rawlings, S. 2000, , 317, 1023
[Skrutskie (2006)]skrutskie06 Skrutskie, M. F., Cutri, R. M., Stiening, R.,  2006, , 131, 1163 
[Smith & Heckman(1989)]smith89 Smith, E. P. & Heckman, T. M. 1989, , 69, 365 
[Smith (2002)]smith02 Smith, J. A., Tucker, D. L., Kent, S.,  2002, , 123, 2121 
[Snellen (2002)]snellen02 Snellen, A. G., Lehnert, M. D., Bremer, M .N., & Schilizzi, R. T. 2002, , 337, 981 
[Spencer (1989)]spencer89 Spencer, R. E., McDowell, J. C., Charlesworth, M., Fanti, C., Parma, P., & Peacock, J. A. 1989, , 240, 657 
[Srianand (2010)]srianand10 Srianand, R., Gupta, N., Petitjean, P., Noterdaeme, P., & Ledoux, C. 2010, , 405, 1888
[Stanghellini (1990)]stanghellini90 Stanghellini, C., Baum, S. A., O'Dea, C. P., & Morris, G. B. 1990, , 233, 379 
[Stanghellini (1993)]stanghellini93 Stanghellini, C., O'Dea, C. P., Baum, S. A.,  & Laurikainen, E. 1993, , 88, 1 
[Stanghellini (1998)]stanghellini98 Stanghellini, C., O'Dea, C. P., Dallacasa, D., Baum, S. A., Fanti, R., & Fanti, C. 1998, , 131, 303
[Stanghellini (2005)]stanghellini05 Stanghellini, C., O'Dea, C. P., Dallacasa, D.,  2005, , 443, 891 
[Stickel & Kuehr(1996)]stickel96 Stickel, M. & Kuehr, H. 1996, , 115, 11
[Tapia (1976)]tapia76 Tapia, S., Craine, E. R., & Johnson, K. 1976, , 203, 291
[Tzanavaris (2005)]tzanavaris05 Tzanavaris, P, Webb, J. T., Murphy, M. T., Flambaum, V. V., & Curran, S. J. 2005, Phys. Rev. Lett, 95, 041301
[Tzanavaris (2007)]tzanavaris07 Tzanavaris, P, Murphy, M. T., Webb, J. T., Flambaum, V. V., & Curran, S. J. 2007, , 374, 634
[Uson (1991)]uson91 Uson, J. M., Bagri, D. S., & Cornwell, T. J. 1991, Phys. Rev. Lett., 67, 3328
[van Gorkom (1989)]vang89 van Gorkom, J. H., Knapp, G. R., Ekers, R. D., Ekers, D. D., Laing, R. A., & Polk, K. S. 1989, , 97, 708 
[van Langevelde (1995)]vanlang95 van Langevelde, H. J., van Dishoeck, E. F., Sevenster, M. N., & Israel, F. P. 1995, , 448, L123
[Vermeulen (2003)]ver03 Vermeulen, R. C., Pihlström, Y. M., Tschager, W.,  2003, , 404, 861
[White & Becker(1992)]white92 White, R. L. & Becker, R. H. 1992, , 79, 331
[Wilkinson (1994)]wilkinson94 Wilkinson, P. N., Polatidis, A. G., Readhead, A. C. S., Xu, W., & Pearson, T. J. 1994, , 432, L87  
[Wills & Lynds(1978)]wills78 Wills, D. & Lynds, R. 1978, , 36, 317 
[Wolfe & Burbidge(1975)]wolfe75 Wolfe, A. M. & Burbidge, G. R. 1975, , 200, 548 
[Wright, Ables & Allen(1983)]wright83 Wright, A. E., Ables, J. G., & Allen, D. A. 1983, , 205, 793
[Wright(2006)]wright06 Wright, E. L. 2006, , 118, 117 
[Xiang (2005)]xiang05 Xiang, L, Dallacasa, D., Cassaro, P., Jiang, D., & Reynolds, C. 2005, , 434, 123 
[Xu (1995)]xu95 Xu, W., Readhead, A. C. S., Pearson, T. J., Polatidis, A. G., & Wilkinson, P. N. 1995, , 99, 297 
[Yan (2012)]yan12 Yan, T., Stocke, J. T., Darling, J., & Hearty, F. 2012, , 144, 124 
[Yan (2016)]yan16 Yan, T., Stocke, J. T., Darling, J., Momjian, E., Sharma, S., & Kanekar, N. 2016, , 151, 74










lllccccccc

Observations of Intrinsic HI and OH Lines Toward Compact Radio Sources
10
0pt

Source     
α     
δ      
z    
ν_ HI    
HI Time      
OH Time     
Class.    
2cReferences


    
(J2000)    
(J2000)     
     
(MHz)    
(sec)    
(sec)    
    
Class.    
Spec. 


0018+729	   	00 21 27.4	   	+73 12 41.9	   	0.821(2)   	780.0(9)   	1493	   	896 	    GPS  	    1      

LBQS 0106+0119 	    	01 08 38.8 	    	+01 35 00.3 	    	2.099(5)    	472.1(8)   	564 	    541	    FSRS	    2	   

COINS J0111+3906   	01 11 37.3	   	+39 06 28.1	   	0.66847(3)	   	851.322(15)	   	1800	       GPS,CSO      1,3,4      1

UM321 		    	01 25 28.8 	    	-00 05 55.9 	    	1.07481(15)   	684.60(5)	   	298	   265	    FSRS	    2	   

3C43		   	01 29 59.8	   	+23 38 20.3	   	1.459	   	577.6	   	1773	   	1725 	    CSS 	    3,5,6,7     

0133+476 	    	01 36 58.6 	    	+47 51 29.1 	    	0.859 	   	764.1	     	293  	    290	    FSRS	    2,8	    

3C48 		    	01 37 41.3 	    	+33 09 35.1 	    	0.367 	   	1038	   	378    	    366	    CSS	    3,5,6	   
       
3C49		   	01 41 09.2	   	+13 53 28.1	   	0.62	   	876.8	   	893	   	    CSS 	    3,5,6,7     2

0138-097 	    	01 41 25.8 	    	-09 28 43.7 	    	0.733 	   	818.6	   	298	    271	    FSRS	    2	   

PKS 0201+113	   	02 03 46.7	   	+11 34 45.4	   	3.6390(10)	   	306.19(7)	   	2377	    	2377     GPS     1     

0212+735 	    	02 17 30.8 	    	+73 49 32.6 	   	2.367 	   	421.9	   	528  	    502	    FSRS	    2,8	    

B2 0218+357         	02 21 05.5 	    	+35 56 13.7 	    	0.944(2)   	730.7(8)        	270 	    264	    FSRS	    2	   

3C066A 		    	02 22 39.6 	    	+43 02 07.8 	    	0.444 	   	982.7	   	299 	    286	    FSRS	    8	   

0221+067 	    	02 24 28.4 	    	+06 59 23.3 	    	0.511 	   	940.0	   	296 	    272	    FSRS	    2,8	   

4C+34.07	   	02 26 10.3	   	+34 21 30.3	   	2.910(2)   	363.28(19)	   	2388	    1763 	    CSS     3,5,6     

HB89 0235+164 	    	02 38 38.9 	    	+16 36 59.3 	    	0.940 	   	732.2	   	281 	   273	    FSRS	    2,8	   

PKS 0237-23	   	02 40 08.2	   	-23 09 15.8	   	2.223	   	440.71	   	1493	   	3284 	    GPS 	    1,3     

PKS 0239+108 	    	02 42 29.2 	    	+11 01 00.7 	    	2.694 	   	384.5	     	322	    309	    FSRS	    2	    

B3 0248+430	   	02 51 34.5	   	+43 15 15.8	   	1.31	   	614.9	   	1493	   	    GPS 	    1,3     3

0306+102 	    	03 09 03.6 	    	+10 29 16.3 	    	0.863 	   	761.4	   	297 	   256	    FSRS	    2,8	   

NGC 1275            	03 19 48.2 	    	+41 30 42.1 	    	0.01765(4) 	   	1395.77(5)	        	278 	       FSRS	    2,8	   

OE+131		   	03 21 52.1	   	+12 21 14.0	   	2.662	   	387.88	   	1472	   	1790 	    GPS,CSS     3,5,6,7    	

PKS 0327-241 	    	03 29 54.1 	    	-23 57 08.8 	    	0.895 	   	748.6	     	278          285 	    FSRS	    2	    
   
0336-019 	    	03 39 30.9 	    	-01 46 35.8 	    	0.852 	   	767.0	   	290 	    288	    FSRS	    2	   

0346-279 	    	03 48 38.1 	    	-27 49 13.6 	    	0.991 	   	712.4	   	297 	    263	    FSRS	    2	   

4C+76.03	   	04 10 45.6	   	+76 56 45.3	   	0.5985	   	888.6	   	818	   	896 	    GPS,CSS     3,5,6,7     2

0420-014 	    	04 23 15.8 	    	-01 20 33.1 	    	0.91609(18)   	741.30(7)     	278 	    297	    FSRS	    2	   

0422+004 	    	04 24 46.8 	    	+00 36 06.3 	    	0.310 	   	1084.3     	266 	    288	    FSRS	    2,8	   

3C119		   	04 32 36.5	   	+41 38 28.4	   	1.023	   	702.1	   	1790	   	1791 	    CSS 	    3,5,6,7     

0440-003 	    	04 42 38.7 	    	-00 17 43.4 	    	0.844 	   	769.3 	    	274	    289	    FSRS	    2	   

PKS 0454-234 	    	04 57 03.2 	    	-23 24 52.0 	    	1.003 	   	708.1 	   	298 	    266	    FSRS	    2	   

PKS 0457+024	   	04 59 52.1	   	+02 29 31.2	   	2.384	   	419.7	   	1791	   	1721 	    GPS 	    1,3    

0458-020 	    	05 01 12.8 	    	-01 59 14.3 	    	2.286 	   	432.3	     	680	    621	    FSRS	    2,8	   

PKS 0500+019	   	05 03 21.2	   	+02 03 04.7	   	0.58457(2)	   	896.398(11)	   	164	    	    GPS      1,3      1

3C138		   	05 21 09.9	   	+16 38 22.1	   	0.76	   	807.1	   	550	   	1790 	    CSS 	    3,5,6     2

PKS 0528-250	   	05 30 08.0	   	-25 03 29.9	   	2.813	   	372.5	   	2651	   	1493 	    GPS 	    1     

PKS 0539-057 	    	05 41 38.1 	    	-05 41 49.4 	    	0.839(3)   	772.4(1.3)	   	298 	   250	    FSRS	    2	   

3C147		   	05 42 36.1	   	+49 51 07.2	   	0.55	   	916.39	   	250	   	1791 	    CSS 	    3,5,6     2

B3 0552+398	   	05 55 30.8	   	+39 48 49.2	   	2.365(5)   	422.1(6)   	1767	   	288	    GPS 	    1     

0605-085 	    	06 07 59.7 	    	-08 34 50.0 	    	0.872 	   	757.8	     	516 	    489	    FSRS	    2	   	

0607-157 	    	06 09 41.0 	    	-15 42 40.7 	    	0.3240(10) 	   	1072.8(8)  	   	263 	    149	    FSRS	    2    

HB89 0636+680	   	06 42 04.3	   	+67 58 35.6	   	3.1800(10)	   	339.81(8)	   	1941	    896 	    GPS     1     

B2 0711+35	   	07 14 42.8	   	+35 34 39.8	   	1.62	   	542.1	   	2302	   	2293 	    GPS  	    1     

0735+178 	    	07 38 07.4 	    	+17 42 19.0 	    	0.424 	   	996.5	     	298 	    381	    FSRS	    2,8	   	

0736+017 	    	07 39 18.0 	   	+01 37 04.6 	    	0.189410(9)    	1192	     	349 	    321	    FSRS	    2,8	   	

B2 0738+31	   	07 41 10.7	   	+31 12 00.2	   	0.6314(16)	   	870.7(9)   	1194	    1742 	    GPS 	    1,3     2

PKS 0742+10	   	07 45 33.1	   	+10 11 12.7	   	2.624(3)   	391.9(3)   	1681	   	1681 	    GPS 	    1,3      5 

PKS 0743-006	   	07 45 54.1	   	-00 44 17.5	   	0.994	   	712.3	   	278	   	1182 	    GPS 	    1,3    

3C186		   	07 44 17.5	   	+37 53 17.2	   	1.0670(19)	   	687.2(6)   	1790	   	1790 	    CSS     3,5,6     

PKS 0745+241 	    	07 48 36.1 	    	+24 00 24.1 	    	0.4092(10) 	   	1008.0(7)	     	271  	    245 	    FSRS	    2,8	   

0748+126 	    	07 50 52.0 	    	+12 31 04.8 	    	0.889 	   	750.9	     	283 	    297	    FSRS	    8,9	    	

COINS J0753+4231   	07 53 03.3	   	+42 31 30.8	   	3.5892(8)	   	309.51(5)	   	2687	   	2687     CSO     4     

HB89 0754+100 	    	07 57 06.6 	    	+09 56 34.9 	    	0.2660(10) 	   	1122.0(9)	     	232 	    390 	    FSRS	    2,8	   

3C190		   	08 01 33.5	   	+14 14 42.4	   	1.1944(12)	   	647.3(4)   	528	   	    CSS     3,5,6     4

SBS 0804+499 	    	08 08 39.7 	    	+49 50 36.5 	    	1.430(2)   	584.5(5)     	596 	    592	    FSRS	    2	     

PKS 0823+033 	    	08 25 50.3 	    	+03 09 24.5 	    	0.506 	   	942.2	     	262 	    285	    FSRS	    8,8	   

PKS 0823-223 	    	08 26 01.6 	    	-22 30 27.2 	    	0.910 	   	742.7	     	298 	    283	    FSRS	    9	   

0828+493 	    	08 32 23.2 	    	+49 13 21.0 	    	0.548 	    	916.6	     	256 	    292	    FSRS	    2	   

0836+710 	    	08 41 24.7 	    	+70 53 42.2 	    	2.1720(10)  	    	447.80(14) 	      	291    	    260	    FSRS	    2,8	    

OJ+287 		    	08 54 48.9 	    	+20 06 30.6 	    	0.306  	   	1087.6 	      	270  	        FSRS	    2,8	     

PKS 0858-279	   	09 00 40.0	   	-28 08 20.3	   	2.152	   	450.6	   	400	   	    GPS 	    1     

TXS 0902+490	   	09 05 27.5	   	+48 50 50.0	   	2.6887(11)	   	385.07(11)	   	1433	   	1493     GPS     1     

0906+015 	    	09 09 10.1 	    	+01 21 35.6 	    	1.020(3)    	701.8(1.1) 	      	290  	    285	    FSRS	    2,8	     	

3C216		   	09 09 33.5	   	+42 53 46.5	   	0.6703(12)	   	850.4(6)   	1492	   	3581 	    CSS     5,6     2

0917+449 	    	09 20 58.5 	    	+44 41 54.0 	    	2.1899(2)  	    	445.28(3) 	      	577  	    369	    FSRS	    2,8	     

0919-260 	    	09 21 29.4 	    	-26 18 43.4 	    	2.300 	   	429.4	     	597	    592	    FSRS	    2	   	

0923+392 	    	09 27 03.0 	    	+39 02 20.9 	    	0.6952(3) 	   	837.90(15)	     	298 	    274	    FSRS	    2	   

0925-203 	    	09 27 51.8 	    	-20 34 51.2 	    	0.34741(15)   	1053.71(2)     	298 	    526	    FSRS	    2	   

HB89 0954+556 	    	09 57 38.2 	    	+55 22 57.8 	    	0.896(8)   	749(3)	     	268 	    284	    FSRS	    2	   

HB89 0954+658 	    	09 58 47.2 	    	+65 33 54.8 	    	0.368 	   	1037	     	292 	       FSRS	    2	   

1004+141 	    	10 07 41.5 	    	+13 56 29.6 	    	2.707(5)   	383.2(5)     	519 	    517	    FSRS	    2,8	   

3C237		   	10 08 00.0	   	+07 30 16.4	   	0.87	   	759.6	   	1785	   	1771 	    CSS 	    3,5,6     

PKS 1034-293 	    	10 37 16.1 	    	-29 34 02.8 	    	0.312 	   	1082	     	582 	    562	    FSRS	    2	   

1055+018 	    	10 58 29.6 	    	+01 33 58.8 	    	0.888(5)    	752(2)	     	243 	    266	    FSRS	    2,8	   

1116+128 	    	11 18 57.3 	    	+12 34 41.7 	    	2.129(2)    	454.0(3)     	567 	    542	    FSRS	    2,8	   

PKS 1124-186 	    	11 27 04.4 	    	-18 57 17.4 	    	1.050 	   	691.9  	   	249 	    289	    FSRS	    2,9	   

B3 1144+402 	    	11 46 58.3 	    	+39 58 34.3 	    	1.0880(10) 	   680.3(3)     	262 	    296	    FSRS	    2,8	   

FBQS J1159+2914     	11 59 31.8 	    	+29 14 43.8 	    	0.7245(11)   	823.7(5)   	298 	    291	    FSRS	    2,8	   2

1202-262 	    	12 05 33.2 	    	-26 34 04.5 	    	0.789 	   	794.0  	   	291 	    286	    FSRS	    2	   

B2 1219+28 	    	12 21 31.7 	    	+28 13 58.5 	    	0.102 	   	1288  	   	596 	       FSRS	    2	   

1222+037 	    	12 24 52.4 	    	+03 30 50.3 	    	0.9556(11) 	   726.3(4)     	261	   290	    FSRS	    2,8	   

PG 1222+216 	    	12 24 54.5 	    	+21 22 46.4 	    	0.4320(10) 	   991.9(7)     	299 	    273	    FSRS	    2,8	   

B2 1225+36	   	12 27 58.7	   	+36 35 11.8	   	1.973(2)   	477.8(3)   	300	   	    GPS,CSS     1,3,5,6     

3C273 		    	12 29 06.7 	    	+02 03 08.6 	    	0.15834(7) 	   1226.24(7)     	595	    562	    FSRS	    2,8	   

COINS J1244+4048   	12 44 49.2	   	+40 48 06.2	   	0.813(2)   	783.5(9)   	442	   	2239 	    CSO 	    4    	

3C279 		    	12 56 11.2 	    	-05 47 21.5 	    	0.5362(14) 	      924.6(2)   	269 	    275	    FSRS	    2	   

1308+326 	    	13 10 28.7 	    	+32 20 43.8 	    	0.996 	   	711.6	     	228 	    298	    FSRS	    2,8	   

3C287		   	13 30 37.7	   	+25 09 10.9	   	1.055	   	691.2	   	1790	   1770 	    CSS 	    3,5,6    

3C286		   	13 31 08.3	   	+30 30 33.0	   	0.8494(11)	   768.0(5)   	1194	   1194 	    CSS     3,5,6     

HB89 1333+459	   	13 35 22.0	   	+45 42 38.2	   	2.4490(10)	   411.83(12)   	1750	       GPS     1     

1354+195 	    	13 57 04.4 	    	+19 19 07.4 	    	0.720 	   	824.8  	   	274 	        FSRS	    2,8	   

B3 1355+441	   	13 57 40.6	   	+43 53 59.8	   	0.646	   	862.9	   	844	   	1762 	    GPS,CSO     1,4     2

1418+546 	    	14 19 46.6 	    	+54 23 14.8 	    	0.1526(3)   	1232.4(3)     	272 	    275	    FSRS	    2,8	   	

3C305.1		   	14 47 09.6	   	+76 56 21.8	   	1.132	   	666.2	   	895	   	    CSS 	    3,5,6     

3C309.1		   	14 59 07.6	   	+71 40 19.9	   	0.905	   	745.6	   	896	   	865 	    CSS 	    3,5,6    

1504-166 	    	15 07 04.8 	    	-16 52 30.3 	    	0.876(4)   	757.2(1.6)	     	281	    	    FSRS	    2	   

3C318		   	15 20 05.4	   	+20 16 05.8	   	1.5740(10)	   	551.8(2)   	448	   	896 	    CSS     3,5,6    

COINS J1546+0026   	15 46 09.5	   	+00 26 24.6	   	0.55	   	916.4	   	1782	   	1777 	    GPS,CSO     4    2

B2 1600+33	   	16 02 07.3	   	+33 26 53.1	   	1.1	   	676.4	   	862	   	    GPS,CSS     1,3,5,6    	

PKS 1622-253 	    	16 25 46.9 	    	-25 27 38.3 	    	0.786 	   	794.3  	   	277 	    291	    FSRS	    2	   

PKS 1622-29 	    	16 26 06.0 	    	-29 51 27.0 	    	0.815 	   	781.6	   	266 	    298	    FSRS	    11	   

3C343		   	16 34 33.8	   	+62 45 35.8	   	0.988	   	714.5	   	1194	   	1197 	    CSS 	    3,5,6,7    

1637+574 	    	16 38 13.5 	    	+57 20 24.0 	    	0.7506(10)    	811.4(5)   	265	    214	    FSRS	    2,8	   

3C343.1		   	16 38 28.2	   	+62 34 44.3	   	0.75	   	811.7	   	1800	   	1787 	    CSS 	    3,5,6,7    

1642+690 	    	16 44 07.9 	    	+68 56 39.8 	    	0.751 	   	810.2  	   	290 	    261	    FSRS	    2,8	   2

1656+053 	    	16 58 33.5 	    	+05 15 16.4 	    	0.879 	   	754.9  	   	282 	    261	    FSRS	    2,8	   

1730-130 	    	17 33 02.7 	    	-13 04 49.5 	   	0.902 	   	745.8	   	284 	    280	    FSRS	    2	   

1741-038 	    	17 43 58.9 	    	-03 50 04.6 	    	1.054 	   	691.5	     	271 	    298	    FSRS	    2	   

1749+701 	    	17 48 32.8 	    	+70 05 50.8 	    	0.770 	   	801.5  	   	278 	    278	    FSRS	    2,8	   

1803+784 	    	18 00 45.7 	    	+78 28 04.0 	    	0.680 	   	844.5  	   	298	        FSRS	    2,8	   

1800+440 	    	18 01 32.3 	    	+44 04 21.9 	    	0.663 	   	845.1 	      	288  	        FSRS	    2,8	    	

COINS J1815+6127   	18 15 36.8	   	+61 27 11.6	   	0.601(3)   	887.2(1.7)	   	1436	   	2090 	    GPS,CSO     4    	2

1823+568 	    	18 24 07.1 	    	+56 51 01.5 	    	0.6640(10) 	   853.6(5)    	288	    260 	    FSRS	    2	   

3C380		   	18 29 31.8	   	+48 44 16.2	   	0.69	   	840.5	   	597	   	384 	    CSS 	    5,6    	2

4C+29.56	   	18 31 14.9	   	+29 07 10.3	   	0.842(3)   	771.1(1.3)	   	1293	   	1493 	    CSS     3,5,6    	2

WMAP 1849+6705 	    	18 49 16.1 	    	+67 05 41.7 	    	0.6570(10)   	857.2(5)     	283	    296	    FSRS	    2,8	   

TXS 1848+283	   	18 50 27.6	   	+28 25 13.2	   	2.56	   	398.99	   	1791	   	3583 	    GPS 	    1    

TXS 1851+488	   	18 52 28.5	   	+48 55 47.5	   	1.250(3)   	631.3(8)   	597	       GPS 	    1    	

1921-293 	    	19 24 51.1 	    	-29 14 30.1 	    	0.35263(18)   	1050.11(14)     	381	        FSRS	    2	   

PKS 2000-330	   	20 03 24.1	   	-32 51 45.1	   	3.7730(10)	   297.59(6)   	1720	   	1744      GPS     1    

2007+777 	    	20 05 30.9 	    	+77 52 43.1 	    	0.342 	   	1058.4     	394	        FSRS	    2,8	   	

PKS 2008-068	   	20 11 12.2	   	-06 44 03.6	   	0.5470(10)	   	918.2(6)   	1740	   	1791 	     GPS     1,3,7    

COINS J2022+6136    	20 22 09.7 	    	+61 36 58.8 	    	0.227 	   	1157 	   	258 	    285	    GPS	    12	    2

2059+034 	    	21 01 38.8 	    	+03 41 31.3 	    	1.013 	   	705.6	     	242	    290	    FSRS	    2	    

PKS 2121-01	   	21 23 39.1	   	-01 12 34.7	   	1.158(2)   	658.2(6)   	299	   	    GPS,CSO     1,10    

PKS 2126-15	   	21 29 12.2	   	-15 38 41.0	   	3.2680(10)	   	332.80(8)	   	3583	   	3583     GPS     1,3    

PKS 2127+04	   	21 30 32.9	   	+05 02 17.5	   	0.99	   	713.8	   	893	   	896 	    GPS 	    1,3    	

2128-123 	    	21 31 35.3 	    	-12 07 04.8 	    	0.501 	   	945.3  	   	384 	    366	    FSRS	    2	   

PKS 2134+004	   	21 36 38.6	   	+00 41 54.2	   	1.9320(10)	   	484.45(17)	   	1791	   	    GPS     3    

PKS 2135-209	   	21 37 50.0	   	-20 42 31.7	   	0.63634(3)   	868.04(2)   	   	1682 	    CSS 	    6    	2

2145+067 	    	21 48 05.5 	    	+06 57 38.6 	    	0.990 	   	712.8  	   	282 	       FSRS	    2,8	   

PKS 2149+056	   	21 51 37.9	   	+05 52 13.0	   	0.740(10)	   	816.3(5)   	1790	   	    GPS     1    	1

2155-152 	    	21 58 06.8 	    	-15 01 09.3 	    	0.672 	   	848.5  	   	278 	    386	    FSRS	    2	   

2201+315 	    	22 03 15.0 	    	+31 45 38.3 	   	0.2950(5) 	   	1096.8(4)	     	398	    280	    FSRS	    2,8	   

2216-038 	    	22 18 52.0 	    	-03 35 36.9 	    	0.901 	   	746.2 	   	281 	    255	    FSRS	    2	   

PKS 2230+11	   	22 32 36.4	   	+11 43 50.9	   	1.037	   	697.3	   	1752	   	1791 	    CSS 	    5,6    	

2234+282 	    	22 36 22.5 	    	+28 28 57.4 	    	0.795 	   	790.3  	   	288 	    362	    FSRS	    2,8	   

3C454.1		   	22 50 32.9	   	+71 29 19.2	   	1.841	   	499.97	   	896	   	    CSS 	    3,5,6    

3C454		   	22 51 34.7	   	+18 48 40.1	   	1.757	   	515.2	   	1316	   	1752 	    CSS 	    3,5,6    

3C454.3 	    	22 53 57.8 	    	+16 08 53.6 	    	0.859 	   	763.1  	   	252 	    266	    FSRS	    2,8	   

3C455		   	22 55 03.9	   	+13 13 34.0	   	0.543	   	920.6	   	1790	   	1791 	    CSS 	    3,5,6     2

2255-282 	    	22 58 06.0 	    	-27 58 21.3 	    	0.92584(15)   737.69(6)	     	273 	    296	    FSRS	    2	   

3C459		    	23 16 35.2 	   	+04 05 18.1 	    	0.22012(3)        1164.15(3)    	   	292         286	    CSS	   13   

HB89 2342+821	   	23 44 03.8	   	+82 26 40.4	   	0.735	   	818.7	   	1791	   	1752 	    GPS,CSS     1,3,5,6     2	

HB89 2344+092 	    	23 46 36.8 	    	+09 30 45.5 	    	0.677 	   	847.0  	   	298 	    263	    FSRS	    2,8	   
Columns list the source name, Right Ascension and
  Declination, optical redshift, expected frequency of the corresponding HI
  21 cm line, total integration times for each reduced spectra, radio
  source classification (GPS, CSS, CSO, FSRS), references for the
  classification, and references for any previous HI 21 cm observations.
  Numbers in parentheses indicate uncertainties in the final digit(s) of
  listed quantities, when available. 
 
Classification references: 
1 – <cit.>;
2 – <cit.>; 
3 – <cit.>; 
4 – <cit.>; 
5 – <cit.>; 
6 – <cit.>; 
7 – <cit.>; 
8 – <cit.>; 
9 – <cit.>; 
10 – <cit.>; 
11 – <cit.>;  
12 – <cit.>; 
13 – <cit.>. 

Previous spectroscopy of the HI 21 cm line references:
1 – <cit.>;
2 – <cit.>; 
3 – <cit.>;
4 – <cit.>;
5 – <cit.>.   







lcccccccccc 

HI 21 cm Line Observations, Column Densities, and Source Sizes 
11
0pt

Source     
z      
ν     
Δ v     
rms      
Ctnm     
N_ HI    
Prev. N_ HI     
2cSize    
Ref.

		
     
     
(MHz)    
()    
(mJy)     
(Jy)    
2c(10^20 cm^-2)    
(arcsec)    
(kpc)    



0018+729	    0.821(2)	    780.0(9)	    -5077, 6080	    3.37	    1.0033(6)	    <0.51        0.018     0.14     1	

LBQS 0106+0119      2.009(5)	    472.1(8)	        RFI	               0.0106    0.09     2	

COINS J0111+3906    0.66847(3)	    853.322(15)	    -1343, 3015	    2.47	    0.153(2)	    74(13)     81(17)^1      0.005     0.04     3

UM321          	    1.07481(15)   	    684.60(5)    	    -3813, 26560    8.3       1.306(18)	    <1.1         0.0048    0.039   4	

3C43		    1.459		    577.6		    -3047, 2470	    12.8	    5.97(4)	    <0.29        2.60     22.2     5

0133+476    	    0.859		    764.1 	        RFI 	               0.0029   0.022     2	

3C48       	    0.367 	    1038    	    -432, 568       4.9       20.04(4) 	    <0.037        0.50      2.5      5	

3C49		    0.62		    876.8		        RFI	           1.1^2     0.99     6.7     3

0138-097   	    0.733 	    818.6    	    -2423, 2711     9.9       0.76(12) 	    <1.9         0.0019    0.014    4	

PKS 0201+113	    3.6390(10)	    306.19(7)	    -2976, 10760    7.13	    0.331(8)	    <2.9         0.002     0.015    1

0212+735 	    2.367 	    421.9		        RFI 	               0.0131	    0.108	    2

B2 0218+357  	    0.944(2)  	    730.7(8)   	    -1559, 4882     6.1       1.559(4)  	    <0.64        0.0052    0.037    6 

3C066A   	    0.444   	    982.7    	    -3179, 2840     8.2       2.83(16)  	    <0.47        0.0053    0.030    2 

0221+067   	    0.511   	    940.0    	    -462, 806       5.9       0.961(10)   	    <1.0         0.0035    0.022    4	

4C+34.07	    2.910(2)	    363.28(19)	        RFI	               1.1     8.7     5	

HB89 0235+164       0.940   	    732.2    	    -458, 1628      8.6       1.1(2)	    <1.3         0.0021    0.017    2	

PKS 0237-23	    2.223		    440.71	    -327, 1721	    4.10	    3.42(2)	    <0.21        0.018     0.15     5	

PKS 0239+108 	    2.694 	    384.5		        RFI 	           RFI^8     0.0024	    0.019	    4

B3 0248+430	    1.31		    614.9		        RFI	           <0.78^3     0.06     0.5     5	

0306+102   	    0.863   	    761.4 	    -12690, 1262    8.0       0.47960(2)   	    <2.6         0.0073    0.056    7	

NGC 1275  	    0.01765(4)        1395.77(5)   	    -2242, 2530     4.8  	    23(3)		    <0.035        0.102     0.00361   	2

OE+131		    2.662		    387.88	    -8579, 10542    8.33	    2.689(9)	    <0.63    RFI^8     0.02     0.16     5	

PKS 0327-241 	    0.895  	    748.6 	    -1668, 979      8.3	    0.9197(4) 	    <1.5               

0336-019     	    0.852    	    767.0    	    -3379, 3009     6.5       2.26(8)    	    <0.45        0.0013    0.010   2

0346-279    	    0.991    	    712.4    	    -1366, 418      9.7       1.03(6)    	    <1.6         0.0095    0.076   4	

4C+76.03	    0.5985	    888.6		    -391, 631	    6.75	    6.618(7)	   3.7(1.1)    2.5^2      0.14     0.93     3

0420-014 	    0.91609(18)	    741.30(7)	        RFI 	               0.0017	    0.013	    2

0422+004 	    0.310		    1084.3 	        RFI 	               0.0029	    0.013	    4

3C119		    1.023		    702.1		    -1221, 809	    12.5	    14.0(1.6)	    <0.15        0.08     0.65     5	

0440-003    	    0.844 	    769.3    	    -2391, 1888     8.1       2.37(4)   	    <0.53        0.0078    0.060   4	

PKS 0454-234 	    1.003   	    708.1 	        RFI 	               0.0024    0.019   2	

PKS 0457+024	    2.384		    419.7		    -3714, 6678	    5.23	    0.390(19)	    <2.6         0.0067    0.055     8	

0458-020 	    2.286		    432.3		        RFI 	               0.0046	    0.038	    2

PKS 0500+019	    0.58457(2)	    896.398(11)	    -1191, 314	    7.13	    1.57(7)	   7.1(1.3)    7.0(1.3)^1    0.011     0.073     3

3C138		    0.76		    807.1		    -2775, 2039	    7.76	    11.42(4)	    <0.10    <0.10^2     0.68     5.0     3

PKS 0528-250	    2.813		    372.5		    -5883, 2197	    5.95	    1.6(3.6)	    <0.81        0.010     0.080     4	

PKS 0539-057 	    0.839(3)  	    772.4(1.3) 	    -1497, 2526     8.7 	    0.91(9) 	    <1.5         0.0030    0.023   4 	

3C147		    0.55		    916.4		    -2522, 717	    12	    29.4(6)	    <0.070    <0.085^2     0.94     6.0     3	

B3 0552+398	    2.365(5)	    422.1(6)	    -5078, 6761	    4.83	    0.490(7)	    <1.9         0.003     0.03     8	

0605-085    	    0.872   	    757.8    	    -2297, 1170	    7.5       2.820(14)    	    <0.42        0.0040    0.031   4	

0607-157	    0.3240(10)	    1072.8(8)	        RFI	               0.0146	    0.068	    4

HB89 0636+680	    3.1800(10)	    339.81(8)	    -10896, 11619    7.24     0.119(2)	    <7.9         0.006     0.05     6	

B2 0711+35	    1.62		    542.1		    -375, 4993	    8.52	    0.87(2)	    <1.5         0.006     0.05     8	

0735+178    	    0.424   	    996.5    	    -1511, 1569     4.6  	    2.16(4)  	    <0.34        2.6       14       9	

0736+017    	    0.189410(9)  	    1194.21(2)   	    -1854, 2413     5.8  	    2.54(3)  	    <0.38        0.0036    0.011   4	

B2 0738+31	    0.6314(16)	    870.7(9)	    -840, 2672	    19.2	    1.491(6)	    <2.4     <0.45^2    0.006     0.04     3	

PKS 0742+10	    2.624(3)	    391.9(3)	    -5033, 3071	    5.24	    1.562(6)	    <0.58    <1.4^5      0.010     0.08     5	

PKS 0743-006	    0.994		    712.3		        RFI	               0.005     0.04     5	

3C186		    1.0670(19)	    687.2(6)	    -1719, 2208	    4.34	    2.99(2)	    <0.25        2.2     18     5

PKS 0745+241   	    0.4092(10)  	    1008.0(7)   	    -1890, 2257     4.8 	    1.038(9)  	    <0.73        0.0032    0.017    4	

0748+126    	    0.889   	    750.9    	        RFI  	               0.0018    0.014    4 	

COINS J0753+4231    3.5892(8)	    309.51(5)	    -5318, 13086    8.32	    0.7667(5)	    <1.4         0.0086    0.06     6	

HB89 0754+100       0.2660(10)   	    1122.0(9)    	    -491, 939       4.3       1.1(7)      	    <0.73    <0.83^9     3.7       15       10	

3C190		    1.1944(12)	    647.3(4)	        RFI	           40^4     4.1     34     5	

SBS 0804+499 	    1.430(2)	    584.5(5)	        RFI 	            <5.1^10     0.0012	    0.010	    2

PKS 0823+033        0.506    	    942.2   	    -1880, 1825     5.7 	    1.3(6) 	    <0.76        0.0038   0.023     4	

PKS 0823-223      0.910  	    742.7 	    -2907, 1540     8.6 	    0.64(6)  	    <2.2         0.0025    0.020    11	 

0828+493     	    0.548   	    916.6    	    -1150, 803      7.0       1.01(14)     	    <1.2         0.0064    0.041    6	

0836+710 	    2.1720(10)	    447.80(14)	        RFI 	               0.0087	    0.075	    2

OJ+287 		    0.306		    1087.6	        RFI 	               0.0030	    0.014	    2

PKS 0858-279	    2.152		    450.6		    -1924, 3340	    13.9	    0.86(1)	    <2.9                

TXS 0902+490	    2.6887(11)	    385.07(11)	    -3636, 3916	    6.94	    0.954(4)	    <1.5     <7.2^8     0.013     0.11     1	

0906+015 	    1.020(3)	    701.8(1.1)	        RFI 	               0.0076	    0.062	    3

3C216		    0.6703(12)	    850.4(6)	    -353, 3589	    8.06	    6.41(4)	    1.8(4)     1.2^2     9.2     64.5     3

0917+449 	    2.1899(2)	    445.28(3) 	        RFI 	               0.0028	    0.024	    2

0919-260    	    2.300   	    429.4 	    -4715, 737     4.2  	    0.86(11)   	    <0.90        0.0012    0.010    4	

0923+392    	    0.6952(3)   	    837.90(15)        -1669, 879      8.6  	    3.1(2)     	    <0.39        0.0020    0.014    2	

0925-203    	    0.34741(15) 	    1053.71(2)  	    -1790, 1656     7.9       0.89(9)   	    <1.3              

HB89 0954+556  	    0.896(8) 	    749(3)	    -1837, 862      8.6       4.345(17)   	    <0.32        0.0089   0.071     4	

HB89 0954+658  	    0.368 	    1037  	    -6182, 1058     6.8       0.7635(2)   	    <1.4     <11^6     0.0023   0.012     4	

1004+141   	    2.707(5)   	    383.2(5)    	    -4512, 266      9.4       1.305(15)    	    <1.5     RFI^8     0.0074    0.061    13	

3C237		    0.87		    759.6		    -6394, 4732	    6.29	    9.47(6)	    <0.10        1.3     10.1     5	

PKS 1034-293      0.312   	    1082    	    -1129, 1975     4.4       1.06(11)  	    <0.62        0.013     0.006    2	

1055+018   	    0.888(5)   	    752(2)    	    -3869, 2270	    13        3.759(13)	    <0.54        0.0032    0.025    4	

1116+128 	    2.129(2)	    454.0(3) 	        RFI 	               0.0094 	    0.081	    2

PKS 1124-186	    1.050 	    691.9 	    -2521, 1682     6.8	    0.47(5) 	    <2.6         0.0004    0.003    4	

B3 1144+402  	    1.0880(10)   	    680.3(3)   	    -1316, 2171     9.4 	    0.6038(4)   	    <2.8         0.0059    0.049    7	

FBQS J1159+2914	    0.7245(11)	    823.7(5)	    -7388, 8262     5.1 	    2.25(3)  	    <0.33    <1.8^2     0.036	    0.026	    2

1202-262   	    0.789    	    794.0   	    -640, 1326      5.3       2.2090(10)        <0.36        0.003	    0.03	    4

B2 1219+28   	    0.102    	    1288   	    -807, 1637      6.8       0.9(1.7)          <1.2         0.0072	    0.013	    7

1222+037   	    0.9556(11)        726.3(4)   	    -3436, 2880     8.5       0.85(9)    	    <1.7         0.0015	    0.012	    4

PG 1222+216  	    0.4320(10)   	    991.9(7)  	    -1988, 2095     8.2  	    2.06(9)   	    <0.64        0.0034	    0.019	    2

B2 1225+36	    1.973(2)	    477.8(3)	        RFI	               0.060     0.51     5	

3C273   	    0.15834(7)        1226.24(7)   	    -9459, 2793     4.2       46.69(7)     	    <0.014       0.261	    0.0706    2

COINS J1244+4048    0.813(2)	    783.5(9)	    -2334, 2138	    7.5	    1.62(3)	    <0.70        0.04     0.3     12	

3C279   	    0.5362(4)    	    924.6(2)   	    -1768, 3010     4.4       11.1(2)   	    <0.068       0.0032	    0.020	    2

1308+326 	    0.996		    711.6 	        RFI 	               0.0038	    0.031	    2

3C287		    1.055		    691.2		    -4133, 4190	    4.03	    10.5(3)	    <0.066       0.048     0.39     5	

3C286		    0.8494(11)	    768.0(5)	    -3306, 3466	    6.50	    19.39(9)	    <0.052        3.2     25     5	

HB89 1333+459	    2.4490(10)	    411.83(12)	    -8575, 6741	    4.53	    0.102(2)	    <9.2         1.8     15     6	

1354+195   	    0.720    	    824.8   	    -3694, 2424     8.2       3.13(7)   	    <0.38        0.0123	    0.089	    2

B3 1355+441	    0.646		    862.9		        RFI	          33^2     0.017     0.12     3	

1418+546	    0.1526(3) 	    1232.4(3)  	    -3353, 4972	    6.5 	    0.91(7)	    <1.2     <2.7^6     0.0038	    0.010	    2

3C305.1		    1.132		    666.2		        RFI	               2.34     19     5	

3C309.1		    0.905		    745.6		    -2810, 4021	    7.89	    11.457(5)	    <0.11        2.11     16.5     5	

1504-166   	    0.876(4)    	    757.2(1.6)   	    -5553, 3412     9.7       2.8(2)     	    <0.54        0.0017	    0.0013    2

3C318		    1.5740(10)	    551.8(2)	    -962, 869	    5.89	    6.3(2)	    <0.13        1.05     8.98     5	

COINS J1546+0026    0.55		    916.4		    -2895, 2676	    2.99	    2.027(11)	    <0.25    <0.25^2     0.010     0.06     3

B2 1600+33	    1.1		    676.4		        RFI	               0.06     0.5     5	

PKS 1622-253	    0.786 	    794.3		    -3555, 1566     9.0	    2.44701(15)	    <0.55        0.004	    0.03	    4

PKS 1622-29 	    0.815  	    781.6 	    -2354, 1570     9.3 	    2.830(9)	    <0.50        0.0160	    0.121	    2

3C343		    0.988		    714.5		    -3491, 2250	    5.68	    8.56(7)	    <0.11        0.20     1.6     5	

1637+574   	    0.7506(10)        811.4(5)   	    -8992, 3641     6.2  	    0.9(3)   	    <0.99        5.3	    39	    9

3C343.1		    0.75		    811.7		    -3494, 3306	    5.52	    7.28(6)	    <0.11        0.24     1.8     5	

1642+690   	    0.751    	    810.2   	    -7376, 2826     8.2  	    1.87(5)   	    <0.64    <1.3^2     0.0041	    0.030	    2

1656+053   	    0.879    	    754.9   	    -2892, 2922     9.4  	    1.93(5)   	    <0.77        2.4	    19	    9

1730-130   	    0.902    	    745.8   	    -7145, 6534     11  	    6.7(2)   	    <0.27        0.0045	    0.035	    2

1741-038 	    1.054		    567.3		        RFI 	               0.0016	    0.013	    2

1749+701   	    0.770    	    801.5   	    -5764, 2998     6.9       1.3(8)     	    <0.78        0.0047	    0.035	    2

1803+784   	    0.680    	    844.5   	    -2230, 2474     6.0  	    2.1(2)   	    <0.41        0.0016	    0.011	    2

1800+440 	    0.663		    845.1 	        RFI 	               0.0009	    0.006	    2

COINS J1815+6127    0.601(3)	    887.2(1.7)	    -1693, 2244	    2.64	    0.53(6)	    7(3) 	     4.4^2     0.010     0.068     3

1823+568 	    0.6640(10)	    853.6(5)	        RFI 	               0.0061      0.043        2	

3C380		    0.69		    840.5		    -3688, 4958	    12.4	    21.7(2)	    <0.081    <0.19^2     1.3     9.0     3

4C+29.56	    0.842(3)	    771.1(1.3)	    -1656, 1998	    1.86	    3.90(1)	    <0.19    <1.6^2     2.9     20     3	

WMAP 1849+6705	    0.6570(10)	    857.2(5) 	        RFI 	               0.0026	    0.018	    2

TXS 1848+283	    2.56		    398.99	    -445, 6101	    6.55	    0.181(6)	    <7.6                 

TXS 1851+488	    1.250(3)	    631.3(8)	        RFI	               0.005     0.04     6	

1921-293 	    0.35263(18)	    1050.11(14)	        RFI 	               0.0067	    0.033	    2

PKS 2000-330	    3.7730(10)	    297.59(6)	    -4352, 3697	    10.2	    0.16(3)	    <9.5                 

2007+777 	    0.342		    1058.4	    -846, 970	    4.2 	    1.01(10) 	    <0.64    <1.8^6     0.0048	    0.023	    13

PKS 2008-068	    0.5470(10)	    918.2(6)	    -1858, 340	    3.70	    2.135(9)	    <0.30        0.30     0.19     5	

COINS J2022+6136    0.227 	    1157 		    -9869, 1621     7.2	    1.99(15)   	    <0.61    <0.36^ 2     0.010	    0.036	    5

2059+034 	    1.013		    705.6		        RFI 	               0.0016	    0.013	    4

PKS 2121-01	    1.158(2)	    658.2(6)	    -944, 20	    49	    1.548(7)	    <6.0     <6.9^7     0.088     0.73     14	

PKS 2126-15	    3.2680(10)	    332.80(8)	    -4982, 4118	    5.68	    0.101(9)	    <7.2         0.008     0.06     5

PKS 2127+04	    0.99		    713.8		    -972, 1365	    6.03	    5.04(8)	    <0.20        0.030     0.24     5	

2128-123   	    0.501    	    945.3   	    -1527, 9545     6.3  	    1.84(3) 	    <0.59        0.0105	    0.0633    4

PKS 2134+004	    1.9320(10)	    484.45(17)	        RFI	               0.002     0.017     5	


2145+067   	    0.990    	    712.8   	    -1432, 993      14        3.355(2)   	    <0.68        0.0071	    0.057	    2

PKS 2149+056	    0.740(10)	    816.3(5)	    -3595, 1873	    3.39	    0.507(3)	    <0.98    <5.8^ 1     0.004     0.03     3	

2155-152 	    0.672    	    848.5   	    -2189, 1779     8.3  	    2.68(16) 	    <0.43        0.0072	    0.051	    2

2201+315   	    0.2950(5)    	    1096.8(4)   	    -1521, 1395     9.5  	    1.9(2.2)   	    <0.48        0.0054	    0.024	    2

2216-038   	    0.901    	    746.2   	    -2745, 1660     9.9       1.372(2)    	    <1.2         0.0005	    0.004	    15

PKS 2230+11	    1.037		    697.3		    -3036, 2899	    4.87	    7.50(9)	    <0.11        2.6     21     16	

2234+282   	    0.795    	    790.3   	    -5071, 4060     8.2  	    0.597(5)  	    <2.1         0.0011	    0.083	    4

3C454.1		    1.841		    499.97	        RFI	               1.6     14     5	

3C454		    1.757		    515.2		    -1670, 897	    7.49	    4.87(3)	    <0.24        0.66     5.6     5	

3C454.3   	    0.859    	    763.1   	    -8290, 1838     9.2  	    13.87(11)  	    <0.10        0.0078	    0.060	    2

3C455		    0.543		    920.6		    -892, 3709	    2.88	    4.45(5)	    1.8(6)     0.42^2     2.6     17     3

2255-282 	    0.92584(15)	    737.69(6)	        RFI 	               0.0050	    0.039	    4

3C459		    0.22012(3)	    1164.15(3) 	    -9191, 3515     4.9	    5.23(3)	    <0.16        1.86   6.55   17

HB89 2342+821	    0.735		    818.7		    -3211, 3413	    5.14	    4.53(4)	    <0.16    <0.16^2     0.267     1.94     3

HB89 2344+092       0.677    	    847.0   	    -5233, 2063     6.4  	    2.233(2)  	    <0.40        0.0092	    0.065	    4Columns list the source name, optical redshift, centroid or expected 
  frequency for the HI 21 cm absorption line, velocity range searched (blue, red limits),
  spectral rms noise in the search region, the continuum flux 
  density at the expected redshifted line frequency, 
  the measured column density or 3σ upper limit, 
  previously measured column
  densities (or upper limits), largest projected
  angular size and linear size, respectively, and references for the continuum source characteristics.  Numbers in
  parentheses show uncertainties in the final digit(s). Detections and non-detections
  assume f=1, and T_s=100 K.  Non-detections also assume a line width of 30 km s^-1 (Sec. <ref>).
 
References for previous HI 21 cm observations (non-detections are converted to our standard linewidth and spin temperature to aid in comparison):  
1 – <cit.>;
2 – <cit.>; 
3 – <cit.>;
4 – <cit.>;
5 – <cit.>; 
6 – <cit.>; 
7 – <cit.>;
8 – <cit.>;
9 – <cit.>;
10 – <cit.>.
References for sizes: 
1 – <cit.>; 
2 – <cit.>;
3 – <cit.>; 
4 – <cit.>; 
5 – <cit.>; 
6 – <cit.>; 
7 – <cit.>;  
8 – <cit.>; 
9 – <cit.>;
10 – <cit.>;   
11 – <cit.>;   
12 – <cit.>;  
13 – <cit.>;  
14 – <cit.>;  
15 – <cit.>;    
16 – <cit.>; 
17 – <cit.>.  













lcccccccccccccccc

OH 18 cm Observations and Column Density Limits

13
0pt

    
    
3c1612 MHz     
    
3c1667 MHz    
    
3c1720 MHz 

 3-5 7-9 11-13 
Source     
z     
ν      
Δ v    
rms     
    
ν      
Δ v    
rms     
    
ν      
Δ v    
rms    
Cntm    
N_OH/ T_x




    
    
(MHz)     
()     
(mJy)    
    
(MHz)     
()     
(mJy)    
    
(MHz)     
()        
(mJy)       
(Jy)    
(10^13 cm^-2 K^-1)

0018+729	    	0.821		    	885.35		    	    	RFI	    		    	915.63	    	-8945, 9866	    	2.41	    		    	944.83	    	    	    	0.9244(5)	    	<6.0

LBQS 0106+0119 		    	2.009		    	535.80		    	-10741, 7163		    	5.5		    		    	554.12		    	-3179,	2231		    	5.5		    		    	571.79		    		-1681,	3562		    		5.1		    	2.7(2)		    	<3.8	

UM321 			    	1.07481	    	777.05		    	-4688, 3492		    	9.1		    		    	803.62		    	-4357,	4894		    	6.1		    		    	829.25		    		    		RFI		    	1.355(18)		    	<8.9	

3C43	    	1.459	    	655.64	    	-153, 1868	    	12.3	    		    	678.06	    	-3188, 491	    	19.1	    		    	699.69	    	-1257, 2514	    	18.2	    	5.25(3)	    	<8.5

0133+476 		    	0.859		    	867.26		    	    	RFI		    		    	896.91		    	-1834,	572		    	3.9		    		    	925.51		    	-1000,	5,900		    	6.1		    	1.983(11)		    	<4.6	

3C48 			    	0.367		    	1179.4		    	-3967, 3659		    	8.1		    		    	1219.7		    	-3755,	3618	    		7.1		    		    	1258.6		    	-5093,	623		    	11.1		    	17.93(4)		    	<0.85	

PKS 0201+113	    	3.6390		    	347.54		    	-3762, 7969	    		9.78		    		    	359.42	    	-4905, 3186		    	10.1		    		    	370.88		    		-10440, 5645		    	11.9		    	0.365(8)	    	<41	

0212+735 		    	2.367		    	478.83		    	    	RFI		    		    	495.21		    	    	RFI		    		    		511.00		    		    		RFI		    	    	

3C066A 			    	0.444		    	1116.5		    	    	RFI		    		    	1154.7		    	-6314, 1215		    		8.1		    		    	1191.5		    		-5660,	2894		    	5.1		    	2.54(14)		    	<7.2	

B2 0218+357	    	0.944	    	829.34	    	-4722, 3917		    	 6.8		    		    	857.69	    	    	 RFI		    		    		885.05		    	     	 RFI		    	1.492(4)	    	<78a	
	
0221+067 		    	0.511		    	1067.0		    	    	RFI		    		    	1103.5		    	    	RFI		    		    		1138.7		    		    		RFI		    	    	

4C+34.07	    	2.91	    		412.34		    	-10626, 7180		    	12.2		    		    	426.43		    	    	RFI	    		    		440.03		    	    	    	3.61(9)a	    		<77a	

HB89 0235+164 		    	0.94		    	831.05		    	-5142, 4598		    	5.6		    		    	859.46		    	-3222, 6719		    	5.4	    		    	886.87		    	-11266,	903	    		5.6		    	1.0(2)		    	<13	

PKS 0237-23	    	2.223		    	500.23		    	    	RFI		    		    	517.33		    	    	RFI	    		    		533.83		    	    	    	    	

PKS 0239+108 		    	2.694		    	436.45		    	-2064, 2710		    	18		    		    	451.37		    	    	RFI		    		    	465.76		    	    	RFI	    	1.41(14)a		    	<281a	

B3 0248+430 		    	1.31		    	697.94		    	-114, 2034		    	7.8		    		    	721.80		    	-1121,	4444		    		7.8		    		    	744.82		    	    		RFI		    	0.782(3)		    	<22	

0306+102 		    	0.863		    	865.40		    	    	RFI		    		    	894.99		    	-9786, 297		    		4.1		    		    		923.53		    		-413,	2378		    		5.4		    	0.48210(2)		    	<20	

OE+131		    	2.662	    		440.26		    	-2956, 2015		    	13.9		    		    	455.31		    	    	RFI	    		    		469.83		    	    	    		2.586(8)a	    		<112a	

PKS 0327-241 		    	0.895		    	850.78		    	-3706, 3729		    	5.6		    		    	879.87		    	    	    		    	907.93	    	    	    	0.8660(4)a	    	<108a

0336-019 		    	0.852		    	870.54		    	    	RFI		    		    	900.30		    	-7791, 2032		    		4.4		    		    		929.01		    		    		RFI		    	2.22(8)	    	<46	
	
0346-279 		    	0.991		    	809.76		    	    	RFI		    		    	837.45		    	-3133, 2595		    		4.5		    		    		864.15		    		-4422,	4,182		    		4.1		    	0.98(6)	    	<8.6	

4C+76.03	    	0.5985	    	1008.6		    	-751, 3081		    	6.32		    		    	1043.0		    	-1713, 2109		    	4.37		    		    	1076.3		    		    		RFI		    	6.243(7)	    	<1.4

0420-014 		    	0.914		    	841.42		    	-3048, 2077		    	5.9		    		    	870.91		    	    	RFI		    		    	897.94		    	-7164,	1240		    	7.9		    	2.02(13)a	    	<49a	

0422+004 		    	0.31		    	1230.7		    	-5819, 2609		    	4.9		    		    	1272.8		    	-3087,	1788		    		5.8	    		    	1313.4		    	-3337,	270		    	3.4		    	0.51(5)	    	<24	

3C119	    		1.023	    		796.95		    	-4292, 2897		    	8.56		    		    	824.20		    	    	RFI	    		    		850.48		    	    	    	13.7(1.7)a		    		<11a

0440-003 		    	0.844		    	874.31		    	    	RFI		    		    	904.21		    	-6562, 3285		    		3.8		    		    		933.04		    	-3392,	142		    	5.7		    	2.60(4)	    	<3.4	

PKS 0454-234 		    	1.003		    	804.91		    	-10165, 2834		    	8.9		    		    	832.43		    	-4239,	6170		    		8.4		    		    		858.98		    		    		RFI		    	1.58(11)	    	<10	

PKS 0457+024	    	2.384		    	476.43		    	    	RFI		    		    	492.72		    	    	RFI	    		    		508.43		    	    	    		    		

0458-020 		    	2.286		    	490.64		    	    	RFI		    		    	507.41		    	    	RFI		    		    		523.59		    		    		RFI		    	    	

3C138	    	0.76	    	916.04	    	-1522, 2154		    	6.61		    		    	947.36		    	-3922, 2256	    		6.84		    		    	977.57		    	-471, 2862		    		7.91		    		10.5(4)		    		<1.4	

PKS 0528-250	    	2.813		    	422.82		    	-3173, 3329		    	2.84		    		    	437.28		    	-1442, 12882		    	11.8		    		    	451.23		    		    	    	1.5(2.9)	    	<19	

PKS 0539-057 		    	0.839		    	876.69		    	    	RFI		    		    		906.67		    		-6194,	4,023		    	4.5		    		    	935.58		    	-4909,	3326	    	6.7		    	0.91(9)	    	<12	

3C147 			    	0.55		    	1040.2		    	-4914, 2349		    	9.1		    		    		1075.7		    		-1361,	2652		    	9.2		    		    	1110.0		    	-4208,	788	    		11.2		    	26.2(6)	    	<0.68	

0605-085 		    	0.872		    	861.23		    	    	RFI		    		    		890.68		    		-7276,	1846		    	6.5		    		    	919.09		    	-6724,	3551	    	5.6		    	2.853(14)	    	<5.4	

0607-157 		    	0.324		    	1217.7		    	-3768, 5588		    	10		    		    		1259.3		    		-4729,	270		    	5.7		    		    	1299.5		    	-837,	737	    	10.2		    	2.30(3)	    	<5.2	

HB89 0636+680	    	3.1800		    	385.70		    	-9194, 13121		    	4.73		    		    	398.89		    	-10496, 9695		    	7.69		    		    	411.61		    	-12972, 6621		    	7.99		    		0.128(2)	    	<173	

B2 0711+35	    	1.62		    	615.36		    	    	RFI		    		    	636.40		    	    	RFI	    		    		656.69		    	    	    		    		

0735+178 		    	0.424		    	1132.2		    	    	RFI		    		    		1170.9		    	-6427,	3814		    		3.8		    		    	1208.2		    	-4904,	5021		    	4.6		    	2.15(5)	    	<4.0	

0736+017 		    	0.191		    	1355.5		    	-4279, 5908		    	3.3		    		    		1401.8		    		-1935,	7488		    	3.6		    		    	1446.5		    		    	RFI		    	2.53(3)	    	<3.2	

B2 0738+31	    	0.63139		    	988.26		    	-2886, 869		    	2.71		    		    	1022.1		    	-1865, 3447		    	2.22		    		    	1054.6		    		    		    		1.68(7)		    	<2.7	

PKS 0742+10	    	2.624	    	444.88	    	    	RFI		    		    	490.09		    	    	RFI	    		    		474.76		    	    	RFI		    	    		

PKS 0743-006	    		0.994		    	808.54		    	-2083, 2225		    	4.79		    		    	836.19		    	-3203, 3073		    	5.6		    		    	862.85		    		-2149, 981		    	15.9		    		0.672(6)		    	<16	

3C186	    	1.067	    	779.99		    	-5121, 5583		    	2.89		    		    	806.66		    	-2110, 1973	    		6.71		    		    	832.38		    	-6641, 2892		    		3.01		    		2.465(19)		    	<5.3

PKS 0745+241 		    	0.4092		    	1144.1		    	-2679, 2352		    	4.5		    		    	1183.2		    	    	RFI		    		    	1220.9		    	    	    	1.007(10)a	    	<92a	

0748+126 		    	0.889		    	853.48		    	    	RFI		    		    		882.67		    	    	RFI		    		    	910.82		    	-4208,	762		    	8.6		    	1.49(4)b	    	<120b	

COINS J0753+4231	    	3.58925	    	351.31		    	-5317, 13086		    	6.39		    		    	363.32		    	-3452,	6552		    	6.59		    		    	374.90		    		-3395, 1195		    	6.81		    	0.7602(2)	    	<13

HB89 0754+100 		    	0.266		    	1273.5		    	-3888, 1997		    	3.8		    		    	1317.0		    	-4774,	4559	    		3.7		    		    		1359.0		    		-3082,	5301	    	3.5	    	1.1(8)		    	<6.7	

SBS 0804+499 		    	1.43		    	663.47		    	    	RFI		    		    		686.16		    	    		RFI	    		    		708.04		    		    		RFI		    	    	

PKS 0823+033 		    	0.506		    	1070.5		    	-2930, 4071		    	4.4		    		    	1107.1		    	-3752,	3288	    		4.6		    		    	1142.5		    	-506,	3005	    		4.2		    	1.3(6)		    	<8.3	

PKS 0823-223 		    	0.91		    	844.10		    	-2593, 2451		    	6.4		    		    	872.96		    	    	RFI	    		    		900.80	    	-6656,	1531		    	5.8		    	0.61(6)a	    	<177a	

0828+493 		    	0.548		    	1041.5		    	-2737, 2733		    	5.1		    		    	1077.1		    	-2476,	4761	    		4.8		    		    		1111.5		    		-4733,	1471	    	3.6	    	0.92(14)	    	<10	

0836+710 		    	2.172		    	508.27		    	    	RFI		    		    		525.65		    	    		RFI	    		    	542.41		    		    		RFI		    	    	

TXS 0902+490	    	2.6887		    	437.07		    	-6130, 1099		    	5.38		    		    	452.02		    	    	RFI	    		    	466.43	    	    	RFI		    	0.907(3)a	    	<124a	

0906+015 		    	1.024		    	796.56		    	-2989, 9129		    	7.8		    		    	823.79		    	-6298,	1890		    		7.9		    		    		850.06		    	-42,	4008		    	6.8	    	1.33(19)	    	<11	

3C216 			    	0.6703		    	965.23		    	    	    		    	998.24		    	-8938, 2114	    		1.5		    		    		1030.01	    		-3762,	3223		    		7.1		    	5.53(4)	    	<0.57	

0917+449 		    	2.1899		    	505.42		    	    	RFI		    		    		522.70		    	    		RFI		    		    		539.37		    		    		RFI		    	    	

0919-260 		    	2.3		    	488.55		    	    	RFI		    		    		505.26		    	-83,	1934	    		18	    		    		521.37		    		    		RFI		    	0.91(11)	    	<42	

0923+392 		    	0.6952		    	951.06		    	-1590, 1090		    	6.7		    		    		983.58		    	-9578,	694		    	5.7		    		    	1014.9		    	-5334,	5004		    		5.5		    	3.0(2)	    	<4.1	

0925-203 		    	0.34741	    	1196.5		    	-4257, 3764		    	4.5		    		    		1237.5		    	-3899,	3857		    	4.9		    		    	1276.9		    	-4849,	4077		    		3.1		    	0.83(8)	    	<13	

HB89 0954+556		    	0.896		    	850.33		    	    	6.5		    		    	879.41		    	    	RFI		    		    	907.45		    	    		6.1		    	4.20(16)a	    	<26a	

1004+141 		    	2.707		    	434.92		    	    	RFI		    		    	449.79		    	    	RFI		    		    	464.13		    	-2629,	2668		    		8.9		    	1.243(13)b	    	<147b

3C237	    	0.87	    	862.16	    	    	RFI		    		    	891.64		    	-579, 2310		    	3.41	    		    	 920.07		    	-1792, 2049		    		3.56	    		8.38(5)		    		<0.95	

PKS 1034-293 		    	0.312		    	1228.8		    	-4432, 9474		    	3.7		    		    		1270.9		    	-4753,	3032		    	5.6	    		    		1311.4		    	-5857,	3287	    		2.9	    	1.09(11)	    	<11	

1055+018 		    	0.888		    	853.94		    	-93,	5524		    	10.2		    		    	883.14		    	    	RFI	    		    		911.30		    	-3883,	4111	    		8.3	    	3.668(13)a	    	<61a

1116+128 		    	2.118		    	515.25		    	    	RFI		    		    		532.87		    	    	RFI		    		    	549.87		    	    		RFI		    	    	

PKS 1124-186 		    	1.05		    	786.45		    	-6650, 10351		    	6		    		    	813.35		    	-7318,	4845		    	3.6	    		    		839.28		    		-7364,	565		    		4.2		    	0.48(4)	    	<15	

B3 1144+402 		    	1.088		    	772.14		    	-8060, 5374		    	5.1		    		    	798.54		    	-5277,	6023		    	4.5	    		    		824.01		    		-7855,	4042		    		6.8		    	0.5286(4)	    	<17	

FBQS J1159+2914		    	0.7245	    	934.9	    	-5702, 760		    	6.4		    		    	966.87		    	-4430,	5238		    	5.6	    		    		997.70		    		-5694,	7502		    		7		    	2.12(3)	    	<5.8	

1202-262 		    	0.789		    	901.19		    	-8552, 3324		    	10.1		    		    	932.01		    	-7042,	2189		    	8.4	    		    		961.73		    		-4231,	4217		    		6.7		    	1.9640(9)	    	<9.7	

1222+037 		    	0.9556		    	824.42		    	-5048, 3716		    	5.6		    		    	852.61		    	-595,	4925		    	4.3	    		    		879.80		    		    		RFI		    	0.94(11)	    	<8.5	

PG 1222+216 		    	0.432		    	1125.9		    	    	RFI		    		    		1164.4		    	-6088,	3182		    		3.9	    		    	1201.45	    		-5118,	3615		    		3.3		    	1.90(9)	    	<4.6	

3C273 			    	0.15834	    	1391.9		    	-3910, 5567		    	9.1		    		    		1439.4		    	-1158,	3840		    	7.1	    		    	1485.3		    		    		    	44.90(8)	    	<0.34	

COINS J1244+4048	    	0.813		    	889.26		    	    	RFI		    		    	919.67		    	-1708,	1731		    	2.77		    		    	949.00		    	-2579,	2558		    	2.78		    	1.54(3)	    	<4.1

3C279 			    	0.5362		    	1049.5		    	-1859, 5568		    	4.7		    		    	1085.4		    	    	RFI		    		    	1120.0		    	-538,	1604		    	4.6		    	10.6(2)a	    	<7.9a	

1308+326 		    	0.996		    	807.73		    	    	RFI		    		    		835.35		    	-4217,	3894		    		6.5		    		    		861.99		    		    		RFI		    	1.17(2)	    	<11	

3C287	    	1.055	    	784.54	    	-1719, 1873		    	3.98		    		    	811.37		    	-1315, 2110	    		4.33		    		    	837.24		    	-4930,	419		    		7.41		    		9.6(3)	    		<0.87	

3C286	    	0.8494	    	871.76	    	    	RFI		    		    	901.57		    	-4224, 3876		    	6.55	    		    		930.32		    	    	    		18.04(9)		    		<2.0	

B3 1355+441	    	0.646	    	979.48	    	-3635, 2832		    	5.61		    		    	1013.0		    	-3173,	5706		    	1.97		    		    	1045.3		    		-4136,	3952		    	1.92		    	0.58460(7)	    	<7.0	

1418+546 	    	0.1526	    	1398.8	    	 -4120, 6168 	    	3.2	    		    	1446.6	    	    	    		    	1492.7	    	    	    	0.92(7)	    	<71a

3C309.1		    	0.905	    		846.32		    	-1603, 3229		    	9.63		    		    	875.25		    	    	RFI	    		    		903.17		    	-3188,	2305		    	10.1		    	10.35(5)a		    	<20a

1504-166 		    	0.876		    	859.40		    	-3070, 6697		    	7.7		    		    	888.78		    	    	RFI	    		    	917.13		    	    	    	2.9(2)a	    	<58a

3C318	    	1.574	    	626.35		    	    	RFI		    		    	647.77		    	    	RFI		    		    	668.43		    	    	    		    	

COINS J1546+0026	    	0.55		    	1040.2		    	-3473, 4136		    	3.3	    		    	1075.7		    	-2280, 3517		    	4.09		    		    	1110.0		    	-2290, 707		    		2.16		    	1.99(1)	    	<4.0	

PKS 1622-253 		    	0.786		    	902.70		    	    	RFI		    		    	933.57		    	    	RFI		    		    	963.34		    		    		RFI		    	    	

PKS 1622-29 		    	0.815		    	888.28		    	    	RFI		    		    	918.66		    	    	RFI		    		    	947.95		    		    		RFI		    	    	

3C343	    	0.988	    	810.98	    	-646, 3490		    	5.47		    		    	838.71		    	-4429,	2920	    		6.68	    		    	865.46		    	    		    		7.67(7)		    	<1.6	

1637+574 		    	0.7506		    	920.96		    	-567, 4804		    	3.6		    		    	952.45		    	    	    		    	982.82		    	    		    	0.9(3)a	    	<83a

3C343.1		    	0.75	    	921.27		    	-744, 1362		    	5.87		    		    	952.78		    	-1425,	1633	    		8.71		    		    	983.16		    	-2476, 3278		    		9.95		    		6.39(5)		    	<3.0	

1642+690 		    	0.751		    	920.75		    	-505, 6691		    	4.8		    		    	952.23		    	    	    		    	982.60		    	    	    	1.62(3)a	    	<61a

1656+053 		    	0.879		    	858.03		    	-340, 6438		    	6.3		    		    	887.37		    	    	RFI	    		    		915.66		    	    	RFI		    	1.84(5)a	    	<76a	

1730-130 		    	0.902		    	847.65		    	-2458, 2989		    	9.5		    		    	876.63		    	    	RFI	    		    		904.59		    	    	RFI		    	6.6(2)a	    	<24a	

1741-038 		    	1.054		    	784.92		    	-4078, 7915		    	10.6		    		    	811.76		    	-8139,	5747		    		5.6		    		    	837.65		    	-5995,	662		    		7.8		    	1.402(8)	    	<7.8	

1749+701 		    	0.77		    	910.86		    	-3895, 5485		    	4.8		    		    	942.01		    	    		    		    		972.05		    	    	    	1.3(7)a	    	<76a

COINS J1815+6127	    	0.601		    	1007.0		    	-957, 1428		    	2.09		    		    	1041.5		    	-2672, 1721		    	2.07		    		    	1074.7		    	-800,	234		    	3.19		    	0.50(5)	    	<8.4	

1823+568 		    	0.664		    	968.89		    	-1643, 6711		    	4.6		    		    	1002.0		    	-4542,	3027		    		5.3		    		    	1034.0		    	    		RFI		    	1.62(5)	    	<6.9	

3C380	    	0.69	    	953.98	    	-197, 2084		    	3.52		    		    	985.44		    	-2666,	1776		    	4.6	    		    		1018.1		    	-1954, 1874		    	5.83		    	18.89(17)	    	<0.52

4C+29.56	    	0.842	    		875.26		    	    	RFI		    		    	905.19		    	    	RFI		    		    	934.06		    		    	    	    	

WMAP J1849+6705 	    	0.657		    	972.98		    	-6507, 7328		    	4.7		    		    	1006.3		    	-3798,	5736		    		5.8		    		    	1038.3		    	-479,	676	    		4.9		    	0.6(1.3)	    	<20	

TXS 1848+283	    	2.56	    	452.87	    	-461, 5279		    	13.6		    		    	468.36		    	    	RFI		    		    	483.29		    	    	    	0.188(6)a	    	<1640a

PKS 2000-330	    	3.7730		    	337.78		    	-7046, 3614		    	11.5		    		    	349.33		    	-3587,	4514		    	11.6		    		    	360.47		    	-4066,	4234		    	9.19		    	0.18(2)	    		<109	

PKS 2008-068	    	0.5470		    	1042.2		    	-240, 2435		    	6.67		    		    	1077.8		    	    	RFI		    		    	1112.2		    	    	    	2.307(10)a	    	<51a	

COINS J2022+6136	    	0.227		    	1314.0		    	-5713, 4098		    	4.8		    		    	1358.9		    	-2892,	7256		    		4.3		    		    	1402.2		    	-3800,	7959		    		4.3		    	2.18(17)	    	<4.6

2059+034 		    	1.013		    	800.91		    	-5387, 6704		    	6.4		    		    	828.30		    	-3730,	6550		    		4.8		    		    	854.71		    	-698,	6352		    	5.6		    	0.342(3)	    	<27	

PKS 2126-15	    	3.2680		    	377.75		    	-4366, 3110		    	5.62		    		    	390.67		    	-4405,	2563		    	8.47		    		    	403.12		    	    	    		0.124(8)	    	<204	

PKS 2127+04	    	0.99	    	810.17		    	-1633, 2659		    	6.08		    		    	837.87		    	-4812, 5707		    	8.27		    		    	864.59		    		    	RFI		    	4.80(6)		    	<3.2	

2128-123 		    	0.501		    	1074.1		    	    	RFI		    		    	1110.8		    	    	RFI		    		    	1146.2	    	    	RFI		    	    	

PKS 2135-209	    	0.63634		    	985.27		    	-2832, 2795		    	4.34		    		    	1019.0		    	-1620, 4348		    	8.22		    		    	1051.5		    		    		RFI		    		4.9(6)		    	<3.4	

2145+067 		    	0.990		    	 810.17		    	-4601, 4,317	    	5.7	    		    		837.87		    	-4663,	597	    		5.2	    		    	864.59	    		    	RFI 		    	 3.304(2)	    	<3.0 
	
2155-152 		    	0.672		    	964.25		    	-2564, 5364		    	6.1		    		    	997.22		    	-9252,	5599		    	5.1		    		    	1029.0		    	-6693,	9330		    		3.9		    	2.79(18)	    	<3.8	

2201+315 		    	0.295		    	1245.0		    	-2175, 3604		    	5.3		    		    	1287.5		    	-3368,	6877		    	5.2		    		    	1328.6		    	-3025,	6452		    		3.6		    	1(3)		    	<5.6	

2216-038 		    	0.901		    	848.10		    	-956, 3852		    	6.3		    		    	877.10		    	    	RFI		    		    	905.07		    	    	RFI	    	1.3460(3)a	    	<78a

PKS 2230+11	    	1.037	    	791.47	    	-1321, 1342		    	5.06		    		    	818.54		    	-3388, 3392		    	12.2		    		    	844.64		    	-2591, 1671		    		4.44		    	7.34(7)	    	<2.1	

2234+282 		    	0.795		    	898.18		    	    	RFI		    		    		928.89		    	-3618,	6097		    	5.6		    		    	958.51		    	-4469,	3851	    		4.5		    	0.626(6)	    	<20	

3C454	    	1.757	    	584.78	    	    	RFI	    		    		604.77		    	    	RFI		    		    	624.06		    	    	    	    	

3C454.3 		    	0.859		    	867.26		    	    	RFI		    		    		896.91		    	    	RFI		    		    	925.51		    	    	    	    	

3C455	    	0.543	    	1044.9	    	    	RFI	    		    		1080.6		    	    	RFI		    		    	1115.1		    	    	    	    	

2255-282 		    	0.92548	    	837.31		    	    	RFI		    		    		865.94		    	    	RFI		    		    	893.56		    	-9961,	1785		    	4.4		    	1.1440(5)b	    	<81b

3C459		    	0.22012	    	1321.4	    	 -4113, 5643 	    	 4.4		    		    	1366.6	    	 -1546, 8940		    	 4.2		    		    	1410.1	    	 -2055, 3132		    	 2.9		    	 4.50(3) 	    	 <2.1 

HB89 2342+821	    	0.735	    	929.24	    	-3036, 3539	    	4.3		    		    	961.01		    	-4314, 3017		    	6.12		    		    	991.66		    	-3579, 2343		    	4.7		    	4.32(4)	    	<3.0	

HB89 2344+092 		    	0.677		    	961.38		    	-3281, 4421		    	4.6		    		    	994.25		    	-5352,	4267		    	4.4		    		    	1026.0		    	-2350,	7585		    		4.2		    	2.198(2)	    	<4.2

Columns list the source name, the optical redshift, and 
  the expeted frequency, the veloctity range searched (blue, red limits), and the spectral rms noise 
  for each of the 1612, 1667, and 1720 MHz OH lines.  The final two columns list the continuum flux density 
  expected at the redshifted 1667 MHz OH line,  
  and the 3σ column density limit for that line, unless otherwise noted (Sec. <ref>).  
  Numbers in parentheses show uncertainties in the final digit(s).   
aSince the 1667 (and 1665) MHz line was not observable due
  to RFI, we use the 1612 MHz line to obtain an upper limit on the OH column density.
  The interpolated continuum corresponds to the redshifted frequency
  of this line.  
bThe interpolated continuum and OH column density limit
  are based on the 1720 MHz OH line.  











lccccccccc 

Intrinsic HI 21 cm Absorption Line Measurements and Derived Quantities
10
0pt

Source     
Comp.     
ν      
z     
Ctnm     
FWHM      
FWHM     
Depth      
τ     
N_ HI 

		
     
    
(MHz)     
    
(Jy)     
(kHz)     
()    
(mJy)     
(10^-2)    
(10^20 cm^-2)


COINS J0111+3906    1     851.373(5)     0.668371(10)    0.153(2)    190(10)	    67(4)      85(2)	    81^+2_-4 	    104^+7_-8

		    2     851.173(9)     0.668763(18)    0.153(2)    142(17)	    50(6)      34(3)	    25^+2_-3 	    24^+3_-4

                    Tot     851.3278     0.6685          0.153(2)      180(20)   	    63(7)      70(8)  	    61(12) 	    74(13)	
  

4C+76.03            1     887.643(3)     0.600199(5)     6.618(7)    132(10)	    45(3)      114(8)	    1.74^+0.12_-0.12 	    1.48^+0.14_-0.15

		    2     887.69(3)      0.60011(5)      6.618(7)    559(90)	    189(29)    36(6) 	    0.53^+0.09_-0.10 	    1.9^+0.4_-0.5

                    Tot     887.648      0.60019         6.618(7)      199(79)        67.2(27)    165(6)   	    2.9(1.1) 	    3.7(1.1) 

                

PKS 0500+019        1     896.324(9)     0.58470(2)      1.57(7)     284(20)	    95(7)      49(3) 	    3.2^+0.1_-0.3	    5.9^+0.5_-0.7

		    2     895.878(9)     0.58549(2)      1.57(7)       77(21) 	    26(7)      25(6) 	    1.6^+0.3_-0.4 	    0.79^+0.2_-0.3

                    Tot     896.299      0.5847          1.57(7)       372(47)        125(16)    58(7)  	    3.0(4)  	    7.1(1.3) 



3C216               1     850.16(2)      0.67075(4)      6.39(4)     214(47)	    75(20)     12(3) 	    0.19^+0.04_-0.05 	    0.28^+0.09_-0.10

		    2     850.37(3)      0.67034(6)      6.39(4)     701(43)	    247(15)    23.4(1.9) 	    0.37^+0.02_-0.03 	    1.74^+0.17_-0.19

                    Tot     850.336      0.6704          6.39 (4)      613(95)        216(33)    37(4)  	    0.44(7)  	     1.8(4)
 

COINS J1815+6127    1     885.945(8)     0.603266(14)    0.53(6)     219(19)	    71(6)      21.9(1.5)	    4.21^+0.03_-0.08	    5.7^+0.7_-1.2

		    2     886.24(2)      0.60273(4)      0.53(6)     167(56)	    56(19)     6.6(6) 	    1.250^+0.011_-0.02    1.4^+0.5_-0.5

                    Tot     885.978      0.6032          0.53          296(88)        100(30)    25(3)   	    3.7(1.1)   	    7(3) 


3C455               1     920.51(1)      0.54313(3)      4.45(5)     309(47)	    101(15)    9.2(1.4)	    0.21^+0.03_-0.04 	    0.40^+0.08_-0.09

		    2     920.34(3)      0.54335(5)      4.45(5)     829(60)	    270(20)    10.3(1.4) 	    0.23^+0.02_-0.03 	    1.20^+0.16_-0.19

		    3     919.55(1)      0.54467(2)      4.45(5)     153(28)	    50(9)         6.5(9) 	    0.15^+0.01_-0.02 	    0.14^+0.03_-0.03

                    Tot     920.376      0.5433          4.45(5)       510(150)       170(50)    20(2)   	    0.57(17) 	    1.8(6) 

Sources for which 21 cm absorption is detected.  Columns
  list the source name, Gaussian component, central frequency, redshift,
  continuum flux density, FWHM width of the line (rest-frame), line depth, peak optical depth, and
  derived column density corresponding to each individual Gaussian component.  For rows labeled with Tot, these measurements correspond to the direct integration for each absorption profile.  
  Numbers in parentheses show statistical uncertainties in the final digit(s). 









lccccccccc 

UV, Optical, Near-IR, and Radio Properties
10
0pt

Source     
B      
V      
R     
K     
z     
D_ L     
log L_ UV    
log L_ Radio    
References

		
     
(mag)     
(mag)    
(mag)    
(mag)    
     
(Mpc)    
(W Hz^-1)    
(W Hz^-1)    



0018+729	   	   	    20.9(i-band)	   	   	0.821	   	5188.7	   	    27.25	   	1

COINS J0111+3906   	   	   	22.00	   	16.69	   	0.66847	   	4023.5	   	20.40	    26.21	   	2,3

UM321          	    	16.72	    	16.44	    	16.30	    	14.41	    	1.07481	    	7303.7	    	24.39	    27.60	    	4,5,6 

3C43		   	21.38	   	   	19.70	   	20.0	   	1.459	   	10635	   	22.27	    28.52	   	7,8

3C48       	    	16.62	    	16.2	    	    	12.72	    	0.367	    	1950.7	    	23.07	    27.83	    	7,6

0138-097   	    	17.1	    	    	17.0	    	14.40	    	0.733	    	4508.2	    	24.13	    27.03	    	10,6
 
PKS 0201+113	   	   	   	19.5	   	16.8	   	3.6390	   	32616	   	24.08	    27.96	   	11

B2 0218+357  	    	    	19.60	    	   	14.84	    	0.944	    	6173.8	    	22.38	    27.56	    	5,6

3C066A   	    	    	    12.85(H-band)	    	12.02	    	0.444	    	2446.5	    	23.75	    27.15	    	12

0221+067   	    	19.65	    	18.97	    	17.78	    	14.41	    	0.511	    	2897.7	    	21.18	    26.81	    	8,5,13
   
HB89 0235+164       	    	19.0	    	16.89	    	10.49	    	0.940 	    	6141.2	    	19.02	    27.39	    	14,15,16
  
PKS 0237-23	   	   	16.6	   	   	13.6	   	2.223	   	17922	   	24.88	    28.61	   	17,18

0306+102   	    	    	21.2	    	19.91	    	15.19	    	0.863	    	5520.8	    	19.78	    26.98	    	19,5,6
   
NGC 1275  	    	14.80	    	13.03	    	12.62	    	11.30	    	0.01765	    	75.6	    	19.06	    25.19	    	20,21,22,6

OE+131		   	   	19.0	   	19.0	   	15.38	   	2.662	   	22347	   	24.27	    28.64	   	7,18,6

PKS 0327-241 	    	    	    	19.31	    	    	0.895	    	5776.9	    	    27.30	    	5
  
0336-019     	    	18.32	    	17.77	    	17.33	    	14.49	    	0.852 	    	5433.4	    	23.13	    27.63	    	4,5,6
 
0346-279    	    	    	    	17.72	    	14.68	    	0.991 	    	6559.7	    	23.38	    27.43	    	5,23
  
4C+76.03	   	   	   	21.2	   	   	0.5985	   	3512.8	   	    27.79	   	24

3C119		   	   	   	20.0	   	15.02	   	1.023	   	6825.3	   	21.91	    28.59	   	7,6

0440-003    	    	18.35	    	17.98	    	17.85	    	    	0.844	    	5370.0	    	23.46	    27.65	    	4,5
 
PKS 0457+024	   	18.78	   	18.5	   	   	   	2.384	   	19528	   	24.23	    27.72	   	4

PKS 0500+019	   	22.5	   	21.35	   	20.68	   	15.43	   	0.58457	   	3413.1	   	20.28	    27.14	   	25,26,27

3C138		   	19.37	   	18.84	   	18.48	   	15.43	   	0.76	   	4714.7	   	22.65	    28.24	   	28,29,6

PKS 0528-250	   	18.16	   	   	   	15.37	   	2.813	   	23900	   	24.63	    28.44	   	30

PKS 0539-057 	    	    	19.9	    	    	14.41	    	0.839	    	5330.5	    	21.93	    27.23	    	31,6

3C147		   	18.45	   	17.8	   	17.21	   	14.56	   	0.55	    	3168.8	    	22.33	    28.36	    	28,49,6

B3 0552+398	   	18.62	   	18.0	   	18.03	   	14.68	   	2.365	   	19338	   	24.29	    27.81	   	8,18,6

0605-085    	    	   	18.5	   	17.70	   	12.41	   	0.872	   	5592.6	   	22.02	    27.74	   	14,5,6

HB89 0636+680	   	17.59	   	   	16.58	   	13.75	   	3.1800	   	27729	   	25.04	    27.41	   	8,6

B2 0711+35	   	   	17.0	   	   	   	1.62	   	12116	   	    27.77	   	18

0735+178     16.28    	15.65	    	15.29	    	10.34	    	0.424	    	2315.3	    	23.14	    26.99	    	32,33
   
0736+017    	    	14.90	    	14.34	    	13.39	    	12.96	    	0.189410    	921.8	    	22.23	    26.33	    	34,35
   
B2 0738+31	   	16.52	   	16.1	   	16.32	   	16.1	   	0.6314	   	3750.9	   	24.16	    27.19	   	8,36,37

PKS 0742+10	   	24	   	23.8	   	23.1	   	   	2.624	   	21857	   	22.23	    28.39	   	38

3C186	   18.50	   	17.97	   	17.67	   	15.68	   	1.0670	   	7194	   	23.42	    27.95	   	32,41

PKS 0745+241      	19.65	    	18.80	    	18.31	    13.90   0.4092    	2219.3	    	21.4	    26.64	    	32,6

COINS J0753+4231    	19.44	   	18.26	   	17.59	   15.47	   3.5892	   	32081	   	24.66	    28.31	   	32,42

HB89 0754+100     	15.76	    	15.22	    	14.91	   11.71	   0.2660	    	1341.3	    	23.01	    26.25	    	32,33

PKS 0823+033       	17.95	    	17.32	    	16.96	   14.42    0.506	    	2863.6	    	22.67	    26.92	    	32,6
  
PKS 0823-223      	    	16.2	    	15.4	    	12.19	    	0.910	    	5897.8	    	23.01	    27.15	    	36,39,40
  
0828+493   	    	20.46	    	19.61	    	19.12	   14.83   0.548	    	3154.5	    	21.44	    26.89	    	32,6
   
PKS 0858-279	   	   	17.0	   	   	13.59	   	2.152	   	17220	   	24.65	    27.99	   	18,6

TXS 0902+490	   	17.74	          17.49      	17.35      15.08   2.6887	   	22621	   	24.71	    28.20	   	32,6

3C216		   	18.96	   	19.05	   	18.22	   	14.86	   	0.6703	   	4037.1	   	22.79	    27.87	   	43,32,41

0919-260    	    	18.05	    	    	18.01	    	15.04	    	2.300	    	18688	    	24.54	    28.04	    	30,5
   
0923+392    	    	17.07	    	17.02	    	16.79	    	14.16	    	0.6952	    	4222.7	    	23.96	    27.60	    	12

0925-203    	    	    	    	16.00	    	13.78	    	0.34741	    	1832.4	    	23.32	    26.42	    	5,35
 
HB89 0954+556     	18.30	    	17.71	    	17.38	   14.19   0.896	    	5784.9	    	23.24	    27.96	    	32,6

HB89 0954+658  	    	    	    	15.75	    	12.43	    	0.368	    	1957.0	    	22.99	    26.41	    	46,40
 
1004+141  	    	18.97	    	18.53	    	18.28	        2.707    	22808	    	24.28	    28.34	    	32

3C237	   	21.49	   	21.14	   	20.95	      0.87	   	5576.6	   	20.89	    28.27	   	32

PKS 1034-293      	18.83	    	18.26	    	17.54	    	12.71	    	0.312 	    	1612.8	    	21.43	    26.4	    	13,5,33
  
1055+018   	    	18.19	    	17.73	    	16.68	    	14.12	    	0.888	    	5720.7	    	22.87	    27.89	    	4,5,6

PKS 1124-186	    	    	    	19.23	    	12.28	    	1.050	    	7051.1	    	21.65	    27.13	    	5,6
 
B3 1144+402 	    	18.97	    	18.25	    	18.12	   13.53    1.0880    	7371.3	    	23.24	    27.27	    	32,6

FBQS J1159+2914     	18.67	    	18.12	    	17.93	   11.47   0.7245	    	4450.9	    	23.00	    27.49	    	32,6
	
1202-262   	    	    	    	15.97(H-band)    	15.04	    	0.789 	    	4938.8	    	22.85	    27.56	    	6
   
B2 1219+28   	    	15.72	    	15.31	    	14.72	    	11.85	    	0.102	    	464.6	    	21.89	    25.33	    	32,15
   
1222+037   	    	19.23	    	18.79	    	18.5	    	    	0.9556	    	6268.6	    	23.07	    27.31	    	4,10

PG 1222+216	    	15.976	    	15.98	    	15.99	   13.07   0.4320	    	2367.6	    	24.27	    26.98	    	32,6

3C273   	    	12.99	    	12.81	    	12.71	    	9.81	    	0.15834	    	748.7	    	24.28	    27.44	    	12,15,35

COINS J1244+4048    	20.68	   	20.22	   	19.97	      0.813	   	5126	   	21.16	    27.45	   	32

3C279   	    	18.01	    	17.75	    	17.11	    	12.58	    	0.5362	    	3072.1	    	22.79	    27.91	    	28,16

3C287    	18.67	   	18.12	   	17.80	   	15.50	   	1.055	   	7093	   	23.32	    28.49	   	32,6

3C286		   	17.51	   	17.25	   	16.5	   	14.88	   	0.8494	   	5412.8	   	25.67	    28.57	   	44,45,10,6

HB89 1333+459 	   	18.00	   	17.91	   	17.89	   15.04   2.4490	   	20183	   	24.55	    27.16	   	32,6

1354+195   	    	16.34	    	16.09	    	15.92	   13.89   0.720	    	4409.6	    	24.17	    27.63	    	32,6
 
1418+546 	    	16.27	    	15.63	    	15.27	   11.43   0.1526	    	718.9	    	22.06	    25.68	    	32,6
 
3C309.1		   	16.4	   	   	   	14.72	   	0.905	   	5857.4	   	24.45	    28.39	   	10,6

1504-166   	    	20.28	    	19.75	    	17.00	    	14.01	    	0.876	    	5624.6	    	20.77	    27.72	    	13,31,8

3C318 	   21.14	   	20.18	   	19.64	   	   	1.5740	   	11689	   	22.38	    28.6	   	32

COINS J1546+0026   	19.73	   	18.9	   	20.1	   	15.43	   	0.55	   	3168.5	   	23.28	    27.2	   	4,6

PKS 1622-253       	20.95	    	    	19.60	    	14.86	    	0.786	    	4915.5	    	21.27	    27.6	    	8,5,6
 
PKS 1622-29        	    	    	15.06(H-band)    	14.15	    	0.815	    	5141.6	    	23.30	    27.69	    	6
 
3C343		   	21.26	   	   	20.6	   	   	0.988	   	6534.9	   	22.34	    28.34	   	8,18

1637+574   	    	17.11	    	16.9	    	16.94	    	13.54	    	0.7506	    	4642.6	    	24.09	    27.14	    	8,31,5,6

3C343.1		   	   	   	20.8	   	   	0.75	   	4638.0	   	    28.03	   	18

1642+690   	    	    	19.2	    	19.38	    	    	0.751 	    	4642.6	    	22.54	    27.39	    	14,5
   
1656+053   	    	17.33	    	16.55	    	16.21	    	14.06	    	0.879	    	5648.5	    	23.88	    27.59	    	13,47,5,35
    
1730-130   	    	    	19.5	    	18.78	    	14.29	    	0.902	    	5833.2	    	23.05	    28.16	    	31,5,6
    
1749+701   	    	    	17.0	    	15.48	    	13.03	    	0.770 	    	4791.7	    	24.21	    27.31	    	14,5,40
   
1803+784   	    	    	15.9	    	15.46	    	14.15	    	0.680	    	4109.2	    	24.51	    27.4	    	31,5,48
    
COINS J1815+6127   	21.27	   	   	19.12	   	   	0.601	   	3530.8	   	20.53	    26.69	   	8

3C380		   	16.26	   	   	16.86	   	14.25	   	0.69	   	4183.8	   	24.99	    28.43	   	8,29,41

4C+29.56	   	21.92	   	   	20.2	   	   	0.842	   	5354.2	   	21.15	    27.86	   	8

TXS 1848+283	   	18.19	   	18.09	   	17.12	   	14.62	   	2.56	   	21307	   	24.52	    26.42	   	49,8,6

PKS 2000-330	   	18.34	   	17.05	   	16.92	   	15.10	   	3.7730	   	34060	   	25.31	    27.66	   	30,13

2007+777   	     	    	    	17.36	    	13.83	    	0.342	   	1795.4	   	22.19	    26.46	   	40,5

PKS 2008-068	   	   	   	21.3	   	   	0.5470	   	3147.5	   	    27.21	   	7

COINS J2022+6136    	19.83	    	    	17.58	    	14.28	    	0.227	    	1119.4	    	19.59	    26.39	    	8,5,6
 
PKS 2121-01	   	   	   	23.3	   	18.18	   	1.158	   	7968.8	   	20.72	    27.74	   	50

PKS 2126-15	   	17.63	   	16.92	   	16.63	   	14.25	   	3.2680	   	28658	   	25.18	    27.37	   	30,13

PKS 2127+04	   	   	   	22.21	   	   	0.99	   	6551.5	   	    28.11	   	50

2128-123   	    	16.15	    	15.97	    	15.79	    	13.33	    	0.501	    	2829.4	    	23.97	    27.06	    	12
    
2145+067   	    	16.63	    	16.25	    	15.06	    	13.48	    	0.990	    	6551.5	    	23.61	    27.94	    	4,5,13
    
PKS 2149+056	   	23.7	   	22.05	   	20.85	   	17.17	   	0.740	   	4561.5	   	19.35	    26.86	   	13

2155-152 	    	18.42	    	18.3	    	17.79	    	14.46	    	0.672	    	4049.7	    	23.20	    27.5	    	15,31,5,33
    
2201+315   	    	15.52	    	15.46	    	14.33	    	12.34	    	0.2950	    	1511.2	    	22.83	    26.61	    	8,31,5,6

2216-038   	    	17.36	    	16.81	    	16.15	    	14.07	    	0.901 	    	5825.2	    	23.43	    27.47	    	4,5,35
   
PKS 2230+11	   	17.75	   	17.33	   	   	13.77	   	1.037	   	6942.2	   	23.72	    28.33	   	45,6

2234+282   	    	18.94	    	    	17.60	    	14.87	    	0.795	    	4985.4	    	22.53	    27.0	    	8,5,6
   
3C454		   	18.64	   	18.52	   	   	   	1.757	   	13402	   	24.09	    28.58	   	4

3C454.3   	    	16.17	    	15.70	    	15.22	    	12.95	    	0.859 	    	5489.0	    	24.02	    28.43	    	4,5,33
   
3C455		   	19.54	   	19.59	   	19.19	   	13.00	   	0.543	   	3119.5	   	22.69	    27.53	   	8,32,29,6

3C459		    	18.31	   	17.44	    	16.78	    	13.99	    	0.22012	   	1081.1	   	21.00	    26.78	   	51,52,6

HB89 2342+821	   	21.77	   	   	20.22	   	15.85	   	0.735	   	4523.4	   	21.13	    27.81	   	8,24,53

HB89 2344+092       	15.96	    	    	14.99	    	13.55	    	0.677	    	4086.8	    	24.57	    27.43	    	8,5,6

Columns list the source name, optical and near-IR magnitudes, luminosity 
  distance calculated according to <cit.>, specific UV and 21 cm radio luminosity in the host galaxy
  reference frame, and references for the magnitudes. For sources with only
  one magnitude listed, we do not calculate a UV luminosity.  
 
Optical band magnitudes references:  
1 – <cit.>;
2 – <cit.>; 
3 – <cit.>; 
4 – <cit.>; 
5 – <cit.>; 
6 – 2MASS; <cit.>; 
7 – <cit.>; 
8 – SuperCOSMOS Sky Survey; <cit.>; 
9 – <cit.>; 
10 – <cit.>; 
11 – <cit.>; 
12 – <cit.>; 
13 – <cit.>; 
14 – <cit.>; 
15 – <cit.>;
16 – <cit.>; 
17 – <cit.>; 
18 – <cit.>; 
19 – <cit.>; 
20 – <cit.>; 
21 – <cit.>; 
22 – <cit.>; 
23 – <cit.>; 
24 – <cit.>; 
25 – <cit.>; 
26 – <cit.>; 
27 – <cit.>; 
28 – <cit.>; 
29 – <cit.>; 
30 – <cit.>;  
31 – <cit.>; 
32 – SDSS DR6; <cit.>; 
33 – <cit.>; 
34 – <cit.>; 
35 – <cit.>; 
36 – <cit.>; 
37 – <cit.>; 
38 – <cit.>; 
39 – <cit.>; 
40 – <cit.>; 
41 – <cit.>; 
42 – <cit.>; 
43 – <cit.>; 
44 – <cit.>; 
45 – <cit.>; 
46 – <cit.>; 
47 – <cit.>; 
48 – <cit.>; 
49 – <cit.>; 
50 – <cit.>; 
51 – <cit.>; 
52 – <cit.>; 
53 – <cit.>.     








We show the normalized spectra for the 102 RFI-free sources searched for intrinsic HI 21 cm (Figure <ref>) and intrinsic OH 18 cm absorption in sources with known OH 21 cm absorption (Figure <ref>). The observable velocity span for each source is a few thousand  above/below with respect to the systemic velocity of the host galaxy and is typically determined by the RFI conditions rather than the spectral bandwidth. Table <ref> lists the measured upper limits to the column densities for the 21 cm absorption line search. Table <ref> lists the upper limits for the OH absorption line search. 























