The synchrotron component study in a spectral energy distribution of
  blazars
  We study the synchrotron component of the spectral energy distribution (SED)
on the sample of 877 blazars using the ASDC SED Builder Tool with available
broadband data from the literature. Our sample includes 423 flat-spectrum radio
sources (FSRQs), 361 BL Lac objects and candidates, and 93 blazars of uncertain
type. We have made an estimation of the synchrotron peak frequency
($\nu_{peak}^{s}$) for the 875 objects and further classified them as high,
intermediate and low synchrotron peaked sources (HSPs/ISPs/LSPs). There are 42
HSPs with $\nu_{peak}^{s} > 10^{16.5}$ Hz, 222 ISPs with $10^{14.5} <
\nu_{peak}^{s} < 10^{16.5}$ Hz, and 611 LSPs with $\nu_{peak}^{s} < 10^{14.5}$
Hz in our sample. We have calculated an average value of $\nu_{peak}^{s}$ to be
$10^{13.4 \pm 1.0}$ Hz for FSRQs and $10^{14.6 \pm 1.4}$ Hz for BL Lacs. We
found out that $\nu_{peak}^{s}$ and the flux density at 4.8 GHz have a
different distribution (as indicated by Kolmogorov-Smirnov test at significance
level 0.05) for the FSRQ and BL Lac blazars, and for the RBL and XBL types of
BL Lacs. Distribution of $\nu_{peak}^{s}$ values is broader for BL Lacs, than
for FSRQs. There are no ultra-high energy peaked objects (with $\nu_{peak}^{s}
> 10^{19}$ Hz) in our BL Lac sample according to our estimations. The
significant part of FSRQs (41%) and small part of BL Lacs (9%) in our sample
could be considered as candidates to the very-low synchrotron peaked blazars
(with $\nu_{peak}^{s} < 10^{13}$ Hz). Our foundations confirm results of the
previous studies made on samples with significantly smaller number of objects.
