title: Searching for $γ$-ray emission from LOTAAS pulsars
authors: Qi-Wei Lu Zhong-Xiang Wang Yi Xing
text: 
  
      
  
  
  
  
     Vol.0 (2015) No.0, 000–000      
               
  
     
  
  
  
     Shanghai Astronomical Observatory, Chinese Academy of Sciences,
               Shanghai 200030, China; wangzx@shao.ac.cn
  
  
  
          Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
  
  	Department of Astronomy, Yunnan University, Kunming 650091, China
  
     
  
  
  
  The LOw-Frequency ARray (LOFAR) has recently conducted a survey 
  (LOFAR Tied-Array All-sky Survey; LOTAAS) for
  pulsars in the Northern hemisphere that resulted in discoveries of 73 new 
  pulsars. 
  For the purpose of studying the properties of these pulsars, we search for 
  their counterparts using the all-sky survey data obtained with the Large Area 
  Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope (Fermi).
  We analyze the LAT data for 70 LOTAAS pulsars (excluding two millisecond pulsars
  and one with the longest known spin period of 23.5 s). We find one candidate
  counterpart to , which should be searched for the pulsation signal once its timing solution is available. 
  For other LOTAAS pulsars, we derive their 0.3–500 GeV
  flux upper limits. In order to compare the LOTAAS pulsars with 
  the known  pulsars, we also derive the 0.3–500 GeV  fluxes 
  for 112 
  of the latter contained in the Fermi LAT fourth source catalog.
  Based on the properties of the pulsars, we derive upper limits on the spin-down luminosities of the LOTAAS
  pulsars. The upper limits are not very constraining but help suggest that
  most of the LOTAAS pulsars probably have < 10^33 erg s^-1 spin-down
  luminosities and are not expected to be detectable with  LAT.
  
  
  
  
  
     Q. Lu, Z. Wang, & Y. Xing            
     Searching for γ-ray emission from LOTAAS pulsars  
  
     Searching for γ-ray emission from LOTAAS pulsars
      Qi-Wei Lu 
        1,2
     Zhong-Xiang Wang
        3,1
     Yi Xing
        1
     
      December 30, 2023
  =============================================================================
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  § INTRODUCTION
             
  
  
  Since the discovery of the first radio pulsar signal in 1967 <cit.>,
  nearly 3000 pulsars have been found <cit.>, resulting from different
  surveys mainly at radio bands. Among them, approximately 2000 are “young" radio
  pulsars (in this paper, “young" pulsars are used to distinguish them
  from most of the others, the old “recycled" millisecond pulsars; MSPs).
  These pulsars are believed to be born in supernova explosions, while in total 
  there are possibly ∼100,000 of them in our Galaxy 
  (e.g., ).
  The new generation radio telescopes such as the Five-hundred-meter Aperture 
  Spherical Telescope (FAST) and the near-future Square Kilometer Array (SKA)
  will potentially be able to find and study most of these pulsars
  (e.g., ) and thus lead to a more complete 
  understanding
  of the physical properties of the radio pulsar population.
  
  Recently, a survey for radio pulsars in the Northern hemisphere at the very
  low frequency range of 119–151 MHz was carried out with the LOw-Frequency 
  ARray (LOFAR; ). This LOFAR Tied-Array All-sky Survey 
  (LOTAAS) has resulted in the discovery of 73 new radio pulsars <cit.>.
  These LOTAAS pulsars probably represent a sample of pulsars that are
  bright at low frequencies and
  are found to have longer spin periods than the known young pulsar 
  population.  It is thus interesting to study their overall properties, checking
  if there are any other differences between them and the known young pulsar 
  population or other pulsar groups based on survey methods.
  
  From the beginning of the  astronomy, it has been learnt
  and pointed out that pulsars are potential high-energy objects with 
  γ-rays emitted from the magnetosphere due to their high
  surface magnetic fields
  (e.g., ). Observations conducted with 
  The Fermi Gamma-Ray Space Telescope (Fermi), which was launched in 2008, 
  have confirmed that pulsars are the dominant 
   sources in our Galaxy <cit.>. The Large Area Telescope (LAT)
  onboard  has been scanning the whole sky at the energy band
  of 0.1–500 GeV and thus far 253 pulsars, according to the latest results
  provided by the  LAT Multiwavelength Coordinating Group (MCG)[https://confluence.slac.stanford.edu/display/GLAMCOG/Public+List+of+LAT-Detected+Gamma-Ray+Pulsars], have been detected with pulsed  emission.
  Among them, 135 are young pulsars. The  properties of these pulsars 
  allow a deep probe into the emission mechanism of pulsars 
  (e.g., ).
  
  Taking advantage of the all-sky  data collected by LAT, we carried out
  the search for  counterparts to the LOTAAS pulsars. The results of any
  detection or upper limits provide constraints on properties of this very 
  low-frequency pulsar sample. In this paper, we report the results from
  our search.  Below in Section 2,  we describe the analysis of the  LAT
  data and provide the results. In Section 3, we discuss the implication
  of the results.
      
  
  
  § LAT DATA ANALYSIS AND RESULTS
  
  
  
  
  
   §.§ LAT data and source models
  
  LAT is a γ-ray imaging instrument that continuously scans the whole 
  sky in the GeV band <cit.>. In the analysis, we selected 0.1–500 GeV 
  LAT events inside a 20^o×20^o region centered at the 
  position of each of our targets.  The time period of the LAT data was
  from 2008-08-04 15:43:36 (UTC) to 2019-08-14 02:23:15 (UTC). 
  The updated Fermi Pass 8 database was used.
  Following the recommendations of the LAT 
  team[http://fermi.gsfc.nasa.gov/ssc/data/analysis/scitools/], 
  we excluded the events with zenith angles larger than 90 degrees (to prevent 
  the Earth's limb contamination) and with quality flags of `bad'.
  
  For each of the targets, we constructed a source model. 
  The sources, which are listed in the 
  Fermi LAT fourth source catalog 
  (4FGL; ) and within a 20 degree radius circular 
  region from a target, were included in the source model. 
  The spectral forms of the sources are provided in 4FGL. 
  In our analysis, we set the spectral parameters of the sources 
  within 5 degrees of a target as free parameters, and fixed
  the other parameters at their catalog values. 
  The background Galactic and extragalactic diffuse 
  spectral models gll_iem_v07.fits and the file iso_P8R3_SOURCE_V2_v1.txt, 
  respectively, were also included in the source model, and
  the normalizations of the two models were set as free parameters.
  
  
  
   §.§ LOTAAS pulsars
  
  
  Among the 73 radio pulsars discovered by LOTAAS, two are MSPs and 
  PSR J0250+58 has the longest spin period (P=23.5 s) among the known pulsars
  <cit.>. We excluded these three pulsars from our target list; 
  the former are presumably exceptions in the LOTAAS pulsar sample 
  and the latter was studied in detail by <cit.>. 
  Assuming power-law emission for each of the LOTAAS pulsars in the source models 
  at their
  positions given in <cit.>, we performed standard binned likelihood 
  analysis of the LAT data using Fermitools. 
  To avoid the relatively large uncertainties of the instrument response 
  function of LAT and the strong background emission (or possible contamination
  from nearby sources) in the Galactic plane in the low energy range 
  of <0.3 GeV, we included events in the energy range of 0.3–500 GeV for 
  the likelihood analysis. We re-fit the source models using gtlike
  to the LAT data. With the fitted source models,
  the Test Statistic (TS) map of a 3^o×3^o region centered 
  at each of the pulsar targets was calculated (using gttsmap). 
  All the catalog sources were included in 
  the source models. A TS value at a given position 
  is a measurement of the fit improvement for including 
  a source at the position, and is approximately the square of the detection 
  significance of the source <cit.>.
  From the TS maps, we found only two possibly detected sources near the positions
  of  and . For the other 68 targets without any significantly
  detected sources at their positions, we derived 95% flux upper limits, which
  are given in Table <ref>.
  lccc
  
  
  
  0.3–500 GeV flux upper limits of 68 LOTAAS pulsars.
  
  
   
  
  	
  		Source     R.A.     Decl.     Flux/10^-13  
  	
  		name     (h:m)     (^∘:')     (erg cm^-2 s^-1) 
  
  		Source     R.A.     Decl.     Flux/10^-13  
  
                  name     (h:m)     (^∘:')     (erg cm^-2 s^-1) 
  
  J0039+35     00:39.1   +35:45   6.3 
  
  		J0059+69   00:59.5   +69:55   14 
  
  		J0100+80   01:00.3   +80:22   4.4 
  
  		J0107+13   01:07.6   +13:25   3.1 
  
  		J0115+63   01:15.6   +63:24   6.1 
  
  		J0121+14      01:22.0     14:16     8.4
  
  		J0139+33   01:40.0   +33:37   2.0 
  
  		J0210+58   02:11.0   +58:44   11 
  
  		
  		J0302+22   03:02.5   +22:50   1.5 
  
  		J0305+11   03:05.1   +11:23   4.9 
  
  		J0317+13   03:17.9   +13:29   5.3 
  
  		J0349+23   03:49.9   +23:41   15 
  
  		J0421+32   04:21.4   +32:54   17 
  
  		J0454+45   04:54.9   +45:28   15 
  
  		J0518+51   05:18.3   +51:25   4.1 
  
  		J0742+43   07:42.6   +43:33   1.9 
  
  		J0811+37   08:11.2   +37:28   1.8 
  
  		J0813+22     08:13.9     22:01     2.2 
  
  		J0857+33   08:57.8   +33:48   4.5 
  
  		J0928+30   09:29.0   +30:38   3.9 
  
  		J0935+33   09:35.1   +33:11   0.88 
  
  		
  		J1226+00   12:26.2   +00:03   7.1 
  
  		J1235-02   12:35.9   -02:05   5.8 
  
  		J1303+38   13:03.3   +38:13   4.1 
  
  		J1334+10   13:34.5   +10:05   3.3 
  
  		J1344+66   13:43.9   +66:33   14 
  
  		J1404+11   14:04.6   +11:57   2.6 
  
  		J1426+52   14:27.0   +52:10   1.7 
  
  		J1529+40   15:29.2   +40:49   9.4 
  
  		J1623+58   16:23.8   +58:49   1.3 
  
  		J1635+23   16:35.1   +23:31   1.8 
  
  		J1638+40   16:38.8   +40:05   8.5 
  
  		J1643+13   16:43.8   +13:25   3.8 
  
  		J1655+62   16:55.9   +62:02   2.0 
  
  		J1657+33   16:57.7   +33:03   6.1 
  
  		J1707+35   17:07.0   +35:56   6.5 
  
  		J1713+78   17:13.5   +78:09   2.2 
  
  		
  		J1722+35   17:22.1   +35:18   3.9 
  
  		J1735+63   17:35.1   +63:19   2.3 
  
  		J1740+27   17:40.5   +27:13   8.5 
  
  		J1741+38   17:41.2   +38:54   7.4 
  
  		J1745+12   17:45.7   +12:51   3.3 
  
  		J1745+42   17:45.8   +42:53   8.9 
  
  		J1749+59   17:49.6   +59:51   1.5 
  
  		J1809+17   18:09.1   +17:04   15 
  
  		J1810+07   18:10.7   +07:03   2.9 
  
  		J1814+22   18:14.6   +22:23   12 
  
  		J1848+15   18:48.9   +15:17   4.9 
  
  		J1849+25   18:49.8   +25:58   14 
  
  		J1910+56   19:10.7   +56:55   0.82 
  
  		J1916+32   19:16.1   +32:24   6.8 
  
  		J1933+53   19:33.0   +53:32   2.7 
  
  		J1953+30   19:53.8   +30:13   3.0 
  
  		J1957-00   19:57.6   -00:01   2.3 
  
  		J1958+56   19:58.0   +56:49   8.3 
  
  		J2006+22   20:06.6   +22:04   3.2 
  
  		J2022+21   20:22.4   +21:11   2.3 
  
  		J2036+66   20:36.8   +66:44   8.3 
  
  		J2051+12   20:51.4   +12:48   2.8 
  
  		J2053+17   20:53.8   +17:18   16 
  
  		J2057+21   20:57.8   +21:26   14 
  
  		J2122+24   21:22.7   +24:24   11 
  
  		J2123+36   21:23.8   +36:24   3.4 
  
  		J2209+22   22:09.9   +21:17   1.6 
  
  		J2306+31   23:06.2   +31:23   6.1 
  
  		J2329+47   23:29.6   +47:42   2.7 
  
  		J2336-01   23:36.6   -01:51   12 
  
  		J2350+31   23:50.7   +31:39   4.9 
  
  	
  
  
  
  
  
    §.§.§ PSR J1017+30
  
  
  There are two  sources, clearly separated with each other, near 
  the position of  with TS 
  values of ∼22 (Figure <ref>). We ran gtfindsrc in 
  Fermitools to determine their positions and obtained 
  R.A.=15450, Decl.=3018 (equinox J2000.0) for the northeast (NE) one 
  and R.A.=15423, Decl.=2985 (equinox J2000.0) for the southwest (SW) 
  one. The 1σ nominal uncertainties are 005 and 004, respectively.
   is 009 away from the position of the NE source, but given 
  the positional
  uncertainty of 3' in the LOTAAS survey <cit.>, the two sources match
  in position (see Figure <ref>), i.e., the NE source could be the  
   counterpart to .
  
  Including the NE and SW sources in the source model,
  we re-performed the likelihood analysis to the 0.3–500 GeV data, in which
  a power law was assumed for the two sources.
  Note that pulsars'  emission
  can generally be described with an exponentially cutoff power law
  <cit.>, but since the detection significance of the NE source was
  low, we chose to use a simple power law instead (we tested the former
  model, but no higher significant results were obtained).
  We obtained Γ= 2.4±0.3 and 
  F_0.3-500= 4±2× 10^-10 photons s^-1 cm^-2 for 
  the NE source with a TS value of 15 (Γ= 1.9±0.3,
  F_0.3-500= 2±1× 10^-10 photons s^-1 cm^-2 for 
  the SW source with a TS value of 16). We also tested to use the data from
  0.1 GeV, Γ was nearly the same but the flux was increased to
  2±1× 10^-9 photons s^-1 cm^-2 and TS≃ 19
  Therefore the NE source was detected at ≃ 4σ.
  
  We extracted the  spectra of the NE source by performing maximum 
  likelihood analysis of the LAT data in 10 evenly divided energy bands in 
  logarithm from 0.1–500 GeV. 
  In the extraction, the spectral normalizations of the sources within 5 
  degree from it were set as free parameters, while all the other parameters 
  of the sources were fixed at the values obtained from the above maximum 
  likelihood analysis. 
  For the results, we kept only spectral data points when TS is greater 
  than 5 (>2σ significance) and derived 95% flux upper limits 
  otherwise. 
  The flux and TS values of the spectral data points are provided in 
  Table <ref>. 
  
  
  Since pulsars'  emission is stable <cit.>, we checked the
  long-term variability of the NE source by calculating its variability 
  index TS_var. Following the procedure introduced in <cit.>,
  we derived fluxes of 14 time bins for its  emission, with 
  each bin containing 300-day data. 
  If the fluxes are constant, 
  TS_var would be distributed as χ^2 with 13 degrees of freedom. 
  Variable sources would be identified with TS_var larger than 27.7
  (at a 99% confidence level).
  The computed TS_var for the NE source is 8.1, indicating that there 
  was no significant long-term variability in its  emission.
  
  
  
  
    §.§.§ PSR J1715+46
  
  
  
  The 0.3–500 GeV  emission near the position of  only 
  had TS∼12 
  (left panel of Figure <ref>), but detailed analysis indicated that
  it was more significant in a high energy range of >16 GeV. 
  We thus calculated the 16–210 GeV TS map of a 3^o×3^o 
  region centered at  and a TS value of ≃ 17 was found
  (right panel of Figure <ref>).
  We ran gtfindsrc to determine the position 
  and obtained R.A.=25891, Decl.=4614 
  (equinox J2000.0) with a 1σ nominal uncertainty of 005. 
   is 009 away from this position. Considering 3' positional
  uncertainty of the radio position, the pulsar matches in position with
  the  source.  
  Using the  position, we re-performed the likelihood analysis.
  The obtained results were Γ= 1.4±0.3,
  F_0.3-500= 5±4× 10^-11 photons s^-1 cm^-2 in 
  the 0.3–500 GeV band (with a TS value of 14), or Γ= 2.2±0.2,
  F_16-210= 1.1±0.5× 10^-11 photons s^-1 cm^-2 
  in the 16–210 GeV band (with a TS value of 16).
  
  Similarly to analysis to the data of , we also extracted the  
  spectrum of  and searched for its long-term variability.
  The obtained spectral data points are provided in Table <ref>. 
  We note that the  emission was only significantly detected 
  in 16.6–38.8 GeV band with a TS value of 17.
  The computed TS_var for  in 16–210 GeV band is 15.3, 
  indicating that there was no significant long-term variability in 
  the  source. 
  
  
  
  
  § DISCUSSION
  
  
  
  Having analyzed  LAT data for 70 young pulsars discovered by LOTAAS,
  we have found that at the positions of two of them,  and , 
  there was a  source respectively. The two sources were faint, 
  and the detection significances were only ≃ 4σ. For the source to , our spectral analysis showed that the
  detection was mostly at the energy range of 16–39 GeV. Such emission
  is not consistent with the general  properties of pulsars, as most of their
  spectra have an exponential cutoff at several GeV <cit.>. 
  Therefore we only suggest the  source at the position of  as
  a candidate counterpart. In the near future, once the timing solution 
  of  is obtained, further data analysis to search for the pulsation signal
  at γ-rays would be able to verify if it is the counterpart.
  For , we derived its 0.3–500 GeV flux upper limit, which is
  2.6× 10^-12 erg cm^2 s^-1.
  
  Because of the lack of the period derivatives Ṗ of the LOTAAS pulsars, 
  their
  properties such as the spin-down luminosities Ė and surface magnetic 
  fields B
  can not be estimated. In Figure <ref>, we show  
  L_γ of the known  pulsars and the luminosity upper limits
  obtained for the LOTAAS pulsars, where for the former see 
  appendix <ref>
  and for the latter their distances were estimated from the dispersion measures
  <cit.>. The former have 
  L_γ≥ 10^32 erg s^-1 and spin period P≤ 0.6 s, 
  where 41 of the gu pulsars have questionable distance values
  (marked with crosses in Figure <ref>; see appendix <ref>).
  We note that the sensitivity limit of the  LAT survey is approximately
  10^-12 erg cm^-2 s^-1 <cit.>, and 
  assuming 1 kpc distance for a pulsar, the luminosity limit would be
  1.2× 10^32 erg s^-1. Thus the  pulsar detection has
  reached this indicative limit (Figure <ref>).
  For a few LOTAAS pulsars, the upper limits are below 10^32 erg s^-1, 
  and several of them have P ≤ 0.6 s. The comparison shows that our search
  is likely sensitive enough and should have been able to detect some of 
  the LOTAAS pulsars if they have  emission similar to those of 
  the  pulsars.
  It is interesting to note that  is right at the range bottom for the
   pulsars,
  which helps not rule out our identification of its  counterpart.
  
  
  
  For  pulsars, relationship L_γ∼Ė^1/2 is often
  considered <cit.>. Thus  efficiency 
  η = L_γ/Ė∼Ė^-1/2. 
  Since for pulsars Ė∼Ṗ/P^3, and considering magnetic
  dipole radiation from pulsars (e.g., ), 
  B∼ (PṖ)^1/2, we can find
  Ė∼ B^2/P^4 and η∼ P^2/B. In Figure <ref>, 
  we show log (η) and log (P) of the  pulsars. A possible trend
  between them is seen. We test to fit the data points with 
  function log(η)=alog(P)+b, and obtain a≃ 1.97 and b≃ -0.05,
   where 41 gu pulsars with questionable distances were not included
  in the fitting.
  This possible trend is close to the relationship η∼ P^2 as well as
  P^2.33 predicted from considering curvature radiation from  pulsars
  (see details in ), while note 
  that B is unknown and probably around 10^12 G. However, since at any
  given log(P), there is a large scatter in log(η), the fit is not
  good (with reduced χ^2∼ 30). We find that we may define a lower limit
  line
  to the data points with log(η)=2.33log(P)-1.5 (Figure <ref>), 
  for which we specifically require η∼ P^2.33 to match 
  the theoretical prediction of curvature radiation from pulsars.
  
  Using this lower limit, we may set constraints on Ė of the LOTAAS 
  pulsars.  Since η= L_γ/Ė≤ L_γ^u/Ė, where 
  L_γ^u is the  luminosity upper limits for the LOTAAS pulsars,
  we then have Ė≤ L_γ^u/η. With the lower limit 
  relationship given above, the upper limits on Ė of the LOTAAS pulsars
  are calculated, which are shown in Figure <ref>. In this calculation
  for , the luminosity of the candidate  counterpart is used. For
  comparison, we also include Ė of the  pulsars in the figure.
  The  pulsars generally have Ė>10^33 erg s^-1, and
  a death line around this value for  emission of pulsars has been 
  considered <cit.>. Most of
  the LOTAAS pulsars have upper limits above this Ė value, and are
  mixed with the  pulsars in Figure <ref>. However because of
  the large scatters of log(η), for example, the solid line possibly
  describing log(η) and log(P) of the  pulsars in Figure <ref>
  would increase η 100 times and thus lower Ė of the LOTAAS pulsars
  100 times correspondingly, which will move most the LOTAAS pulsars below 
  10^33 erg s^-1. In addition, considering the indicative luminosity
  limit of the LAT survey for pulsars and still using this relationship, we have
  log(Ė)=31.79-2.35log(P), which is shown in Figure <ref>.
  Most of the LOTAAS pulsars will also be moved below this detection line.
  Therefore it is possible that most of the LOTAAS pulsars could have low 
  Ė and thus low  emission, not to be expected detectable 
  with  LAT.
  
  
  
  
  As a summary, we have conducted analysis of the  LAT data to search
  for  emission from the newly discovered 70 LOTAAS pulsars, and only found
  a candidate counterpart to one of them, . 
  For this pulsar, once its long-term timing solution 
  is obtained, a search for its pulsation signal in the  emission of
  the candidate can be conducted for the purpose of verifying if it is the
   counterpart.
  We provide the 0.3–500 GeV
  flux upper limits for the non-detections. By comparing the LOTAAS pulsars with
  the known  pulsars, we estimate the Ė upper limits for the LOTAAS
  pulsars. The upper limits are not very constraining, and it is likely that
  most of the LOTAAS pulsars have low, <10^33 erg s^-1 Ė and 
  are not expected to have detectable  emission. 
  
  
  
  We thank anonymous referees for very helpful suggestions.
  This research made use of the High Performance Computing Resource in the Core
  Facility for Advanced Research Computing at Shanghai Astronomical Observatory.
  This research was supported by the National Program on Key Research 
  and Development Project (Grant No. 2016YFA0400804) and
  the National Natural Science Foundation of China (11633007, U1738131). Z.W.
  acknowledges the support by the Original Innovation Program of the
  Chinese Academy of Sciences (E085021002).
  
  
  
  
  
  
  § KNOWN Γ-RAY PULSARS
  
  
  
  There are 121 young  pulsars listed in 4FGL <cit.>. 
  Searching in the Australia Telescope National Facility (ATNF) pulsar 
  catalog <cit.> and references provided at MCG, we found distance values for 112 of them, which are given in Table <ref>. 
   However it can be noted that 53 of 121  pulsars are marked with 
  `gu' at MCG,  which indicates that these pulsars were discovered in 
  LAT data and/or using an LAT seed position. As most of the gu pulsars 
  have not been detected at radio frequencies, they are probably assigned with 
  `heuristic' distances (see ). We searched references for
  gu pulsars in Table <ref> and found no radio detection reported 
  for 41 of them.
  To be cautious, we marked these 41 gu pulsars in Table <ref> with 
  g, indicating that their distance values are questionable.
  
  Using the spectral parameters given in 4FGL, we derived 0.3–500 GeV flux 
  F_0.3-500.  For the pulsars without
  distance uncertainties, we assumed 30% uncertainties (e.g., ).
  We calculated the luminosities from L_γ=4π d^2f_ΩF_0.3-500,
  where d is the distance and f_Ω is the beam correction factor.
  Following <cit.>, we adopted f_Ω=1.
  
  
  
    a Distances without errors are assumed to have 30% uncertainties.
  
    g  pulsars without (reported) radio detection.
  
  lcccccc
  0.3–500 GeV fluxes and luminosities for 112 γ-ray pulsars.
  
  
  Source     P     Distance^a    Ė/10^33    Flux/10^-12     Luminosity 
  
  name    (s)   (kpc)   (erg s^-1)    (erg cm^-2 s^-1)     (10^33erg s^-1) 
   
  Source     P     Distance^a    Ė/10^33    Flux/10^-12     Luminosity 
       
  name     (s)     (kpc)     (erg s^-1)     (erg cm^-2 s^-1)     (10^33erg s^-1) 
   
  J0002+6216^g     0.12     6.36     150     14.7±1.2    71±43 
  
  
  J0007+7303    0.32    1.4±0.3    450    387.2±3.1     91±39 
  
  
  J0106+4855    0.083    3.1±1.1   29     17.5±0.8     20±14
  
  
  
  
  J0205+6449    0.066    1.95±0.04   27000     40.8±1.1   49.9±2.5
  
  
  J0248+6021    0.22    2.0±0.2   210     22.5±1.3   10.8±2.2
  
  
  J0357+3205^g    0.44    0.83   5.9     53.1±1.0     4.4±2.6
  
  
  J0359+5414^g    0.079    3.45   1300     17.7±1.3     25±15
  
  
  J0514-4408    0.32    0.97   2.5     3.9±0.3     0.43±0.27
  
  
  J0534+2200    0.033    2±0.5   460000     1000±17    490±240
  
  
  J0540-6919   0.051    49.7   150000     17.0±1.1   5030±3034
  
  
  J0554+3107^g    0.46    1.9   56     17.0±0.7     7.3±4.4
  
  
  J0622+3749^g    0.33    1.6   27     14.3±0.6     4.4±2.6
  
  
  J0631+0646^g    0.11    4.58    100     15.3±1.4   38±23
  
  
  J0631+1036    0.29    1.0±0.2   170     27.9±1.2     14.7±5.9
  
  
  J0633+0632^g    0.30    1.35    120     80.9±2.3     18±11
  
  
  J0633+1746    0.24    0.25±0.08    32      3700±11     16±10
  
  
  J0659+1414    0.38    0.29±0.03    38     11.3±0.4     0.114±0.024
  
  
  J0729-1448    0.25    3.5±0.4    280      3.6±0.8     3.1±1.0
  
  
  
  
  J0742-2822    0.17    2.1±0.5    140    11.6±1.0     5.5±2.7
  
  
  J0835-4510    0.089    0.28±0.02    6900     7700±27     72±10 
  
  
  J0908-4913    0.11    2.6±0.9   490     15.5±2.5     2.5±1.3
  
  
  
  
  J0940-5428    0.088    3.0±0.5    1900     12.6±.9     0.218±0.074
  
  
  J1016-5857    0.11    2.9±0.6    2600     54.2±3.6     65±27
  
  
  J1019-5749    0.16    10.91    180     17.3±2.3     250±150
  
  
  J1023-5746^g    0.11    2.08    11000     111.7±6.9     58±35
  
  
  J1028-5819    0.091    2.3±0.3    840     204.2±4.7     49±13
  
  
  J1044-5737^g    0.14    1.9    800     82.3±2.6     36±21
  
  
  J1048-5832    0.12    2.7±0.4    2000     150.4±3.3     150±91
  
  
  J1055-6028    0.10    3.83    1200     16.6±1.7     29±18
  
  
  J1057-5226    0.20    0.3±0.2    30     252.8±2.3     0.24±0.33
  
  
  J1057-5851^g    0.62    0.8    17     12.01±0.88     0.92±0.56
  
  
  J1105-6037^g    0.19    1.53   120     21.4±1.7     6.0±3.6
  
  
  J1105-6107    0.063    5±1   2500     15.7±2.0     10.4±4.4
  
  
  
  
  J1112-6103    0.064     4.5     4500     16.4±2.8     40±25
  
  
  J1119-6127    0.41    8.4±0.4   2300     33.5±2.1     280±32
  
  
  J1124-5916    0.14    4.8±0.7   12000     41.6±1.6     120±37
  
  
  
  
  J1151-6108    0.10    2.22    390     9.04±0.93     5.3±3.2
  
  
  J1208-6238^g    0.44    3    1500     30.8±2.5     33±20
  
  
  J1253-5820    0.26    1.64    5     3.26±0.99     1.05±0.71
  
  
  J1341-6220    0.19    12.6    1400     16.9±2.8     320±199
  
  
  J1350-6225^g    0.14    1.3    130     36.9±2.3     7.4±4.5
  
  
  J1357-6429    0.17    2.5±0.5    3100     19.3±1.3     22.22±0.90
  
  
  J1410-6132    0.050    15.6±4.2    10000     18.9±4.7     410±240
  
  
  J1413-6205^g    0.11    2.15    830     155.3±4.8     86±52
  
  
  J1418-6058^g    0.11    1.6±0.7    4900     240±12     100±91
  
  
  J1420-6048    0.068    5.6±0.9    10000     100±11     390±130
  
  
  J1422-6138^g    0.34    4.8    96     51.9±2.7     140±86
  
  
  J1429-5911^g    0.12    1.95    770    81.0±4.3     37±22 
  
  
  J1459-6053^g    0.10    1.84    910     86.2±2.3     35±21
  
  
  J1509-5850    0.089    2.6±0.5    520    97.2±2.8     130±51
  
  
  J1522-5735^g    0.10    2.1    1200     55.8±2.6     29±18
  
  
  J1528-5838^g    0.36    1.1    22     15.4±1.3     2.2±1.4
  
  
  J1531-5610    0.084    2.1±0.3   900     15.7±1.9     15.1±9.3
  
  
  
  
  J1614-5048    0.23    5.15     1600     16.2±4.4     52±34
  
  
  J1623-5005^g    0.085    1.3   270     5.6±3.3     11.4±6.9
  
  
  J1624-4041^g    0.17    1.8    39     23.1±1.1     8.9±5.4
  
  
  
  
  J1648-4611    0.16    4.5±0.7    210    37.7±2.2     90±28 
  
  
  J1702-4128    0.18    4.8±0.6    340    24.2±4.0     45±14 
  
  
  J1705-1906    0.30    0.75    6.1     3.64±0.46     0.24±0.15
  
  
  J1709-4429    0.10    2.3±0.3    1153.2±8.0     930±240
  
  
  
  
  J1718-3825    0.075    3.6±0.4   1300    79.7±4.8     120±27 
  
  
  J1730-3350    0.14    3.49     1200     26.1±4.9     38±24 
  
  
  J1732-3131    0.20    0.6±0.1   150     166.7±3.4     8.2±2.7
  
  
  J1739-3023    0.11    3.07    300     20.0±3.2     23±14
  
  
  J1740+1000    0.15    1.23    230     1.95±0.37     0.35±0.22
  
  
  J1741-2054    0.41    0.38±0.02    9.5      96.3±1.9     1.04±0.11
  
  
  J1746-3239^g    0.20    0.8    33     42.5±2.6     3.3±2.0   
  
  
  J1747-2958    0.10    4.8±0.8    2500     121.3±6.7     92.1±31.1
  
  
  
  
  J1801-2451    0.12    5.2±0.5    2600     24.2±2.6     41.8±9.2
  
  
  J1803-2149^g    0.11    1.3    640     69.8±3.8     14.1±8.5
  
  
  J1809-2332    0.15    1.7±1.0    430     362.3±6.2     34±39
  
  
  J1813-1246^g    0.048    2.63    6200     177.2±4.1     150±88
  
  
  
  
  J1826-1256    0.11    1.55    3600     340.0±8.8     98±59
  
  
  J1827-1446^g    0.50    0.7   14     24.7±1.7     1.44±0.88
  
  
  J1828-1101    0.072     4.77     1600     29.6±5.0     80.3±50.1
  
  
  
  
  J1833-1034    0.062    4.7±0.4    34000    56.4±4.6     110±21 
  
  
  J1836+5925    0.17    0.5±0.3    11     537.7±2.9     5.8±7.0
  
  
  J1837-0604    0.096    4.77    2000     35.2±5.8     96±60
  
  
  J1838-0537^g    0.15    2    5900     9.1±1.0     44±27
  
  
  J1844-0346^g    0.11    4.3    4300     41.8±2.8     92±56
  
  
  J1846+0919^g    0.23    1.53    34     32.0±1.0    8.9±5.4
  
  
  J1853-0004    0.10    5.34    210     10.2±1.7     35±22
  
  
  J1857+0143    0.14    4.57    450     22.3±3.6     56±35
  
  
  J1906+0722^g    0.11    1.91    1000     55.5±5.6     24±15
  
  
  J1907+0602    0.11    3.2±0.3    2800     240.9±5.2     160±31
  
  
  J1913+0904    0.16    3    160     19.3±1.9     21±13
  
  
  J1913+1011    0.036     4.61     2900     11.5±2.5     29±19
  
  
  J1925+1720    0.076    5.06    950     9.1±1.5     28±17
  
  
  J1932+1916^g    0.21    1.5    410     48.9±3.5     13.1±7.9
  
  
  J1932+2220    0.14    10.9    750     3.84±0.98     55±36
  
  
  J1935+2025    0.08    4.6    4600     21.5±1.9     54±33
  
  
  J1952+3252    0.039    2.0±0.5    3700    118.4±2.3     120±64 
  
  
  J1954+2836^g    0.092    1.96    1000     8.8±2.9     41±24
  
  
  J1957+5033^g    0.37    1.36    5.3     20.1±0.63     4.4±2.7
  
  
  J1958+2846^g    0.29    1.95    340    86.3±2.8     39±24 
  
  
  J2006+3102    0.16    6.03    220     8.7±1.4     38±24
  
  
  J2017+3625^g    0.17    0.656    12     56.8±3.8     2.9±1.8
  
  
  J2021+3651    0.10    10±2    3400    424.1±5.4     160±66 
  
  
  J2022+3842    0.08    4.6    4700     14.5±2.1     170±110
  
  
  J2021+4026    0.27    1.5±0.4    120     645.5±8.8     360±190
  
  
  J2028+3332^g    0.18    0.9    35     51.5±1.5     5.0±3.0
  
  
  J2030+3641    0.20    3±1    32     39.2±1.8     230±140
  
  
  J2030+4415^g    0.23    0.72    32     36.7±1.5     2.3±1.4 
  
  
  J2032+4127    0.14    3.7±0.6   270     130.7±3.8     27.6±9.0
  
  
  J2043+2740    0.096    1.8±0.3   56     7.22±0.52     1.89±0.64
  
  
  J2055+2539^g    0.32    0.62    4.9     46.59±0.96     2.1±1.3
  
  
  J2111+4606^g    0.16    2.7    1400    39.6±1.2     35±21 
  
  
  J2139+4716^g    0.28    0.8    3.1      22.48±0.98     1.7±1.0
  
  
  J2208+4056    0.64    0.75    0.81      2.68±0.43     0.18±0.11
  
  
  J2229+6114    0.052    0.8±0.15    22000    187.8±2.7     200±76 
  
  
  J2238+5903^g    0.16    2.83   890      49.7±1.6     47.6±28.6
  
  
  J2240+5832    0.14    7.7±0.7    220     8.4±1.0     53±12
  
  
  
  
  
  
  
  16
  natexlab#1#1
  
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