2 2009 Fermi Symposium, Washington, D.C., Nov. 2-5
Figure 1: The SMA light curves for 3C 454.3. The open
circles represent the 850µm observations, and the open
triangles represent the 1mm observations.
J1751+096) which have conﬂicting classiﬁcations be-
tween Fermi and CGRaBS. Some blazars found in the
calibrator list have been studied extensively (e.g., 3C
279 and 3C 454.3) but the SMA blazars have not been
studied collectively.
Forty-four of the objects in our total blazar sample
were detected by Fermi and can be found in the cata-
log of LAT Bright AGN Sources (LBAS) from Abdo et
al. [7]. J0050-094 has no redshift in either the LBAS
catalog or CGRaBS and is not included in our study.
Of the 43 remaining sources, 14 are BL Lac objects
and 29 are FSRQs, with 0 .03 ≤z≤2.19.
We examined submillimeter light curves for all of
the SMA blazars, with observations beginning in ap-
proximately 2003 (see Figure 1). Typically, the 1mm
band is much more well-sampled in comparison to the
850m band, but visual inspection reveals that the reg-
ularity and quality of observations vary greatly from
source to source. Many of the objects exhibit non-
periodic variability, either in the form of persistent,
low-amplitude ﬂuctuations or higher amplitude ﬂar-
ing behavior.
2.1. Submillimeter Properties
Submillimeter Luminosities. Since we are pri-
marily concerned with comparisons to Fermi observa-
tions, we note that only 129 of theSMA blazars (23 BL
Lacs and 106 FSRQs) were observed by the SMA in
either band during the three months August-October
2008. For these objects, submillimeter luminosities
are calculated in the standard way:
νeLνe = 4πD2
L
νobsFobs
1 + z , (1)
where DL is the luminosity distance, νobs is the fre-
quency of the observed band, and Fobs is the average
Figure 2: Variability index for our sample (top: 1mm,
bottom: 850 µm), with FSRQs as the hatched
distribution and BL Lacs as the solid distribution. There
is no signicant diﬀerence in the class distributions in
either band; the “tail” to the left is populated by objects
with errors larger than the intrinsic variability.
ﬂux (in erg cm−2 s−1 Hz−1) over the three month pe-
riod. We adopt a lambda cold dark matter cosmology
with values of H0 = 71 km s −1 Mpc−1, Ω M = 0.27,
and Λ = 0.73.
Energy Spectral Indices.We derive submillime-
ter spectral energy indices from observations quasi-
simultaneous with the Fermi observations. To be con-
sistent with the use ofαγ, we deﬁne spectral energy in-
dex as νFν = ν−αS and calculate αS from the average
of the energy spectral indices over the corresponding
three months. We only calculate αS for the 16 objects
(8 BL Lacs and 35 FSRQs) with observations at both
1mm and 850µm during this time frame.
3. VARIABILITY ANALYSIS
3.1. Variability Index
We roughly characterize the level of variability of
each source using the variability index from Hovatta
et al. [8]:
V = (Fmax −σFmax ) −(Fmin + σFmin )
(Fmax −σFmax ) + (Fmin + σFmin ) (2)
Figure 2 shows the distribution for theSMA blazars.
Objects with V ≤0 are typically unsuitable for more
eConf C091122