THE SPECTRAL ENERGY DISTRIBUTIONS OF FERMI BLAZARS

摘要

In this paper, multiwavelength data are compiled for a sample of 1425 Fermi blazars to calculate their spectral energy distributions (SEDs). A parabolic function, log (vF(v)) = P-1 (log v -P-2)(2) + P-3, is used for SED fitting. Synchrotron peak frequency (log v(p)), spectral curvature (P-1), peak flux (v(p) F-vp), and integrated flux (vF(v)) are successfully obtained for 1392 blazars (461 flat-spectrum radio quasars [FSRQs], 620 BL Lacs [BLs], and 311 blazars of uncertain type [BCUs]; 999 sources have known redshifts). Monochromatic luminosity at radio 1.4 GHz, optical R band, X-ray at 1 keV and gamma-ray at 1 GeV, peak luminosity, integrated luminosity, and effective spectral indices of radio to optical (alpha RO) and optical to X-ray (alpha OX) are calculated. The "Bayesian classification" is employed to log v(p) in the rest frame for 999 blazars with available redshift, and the results show that three components are enough to fit the log v(p) distribution; there is no ultra-high peaked subclass. Based on the three components, the subclasses of blazars using the acronyms of Abdo et al. are classified, and some mutual correlations are also studied. Conclusions are finally drawn as follows: (1) SEDs are successfully obtained for 1392 blazars. The fitted peak frequencies are compared with common sources from available samples. (2) Blazars are classified as low synchrotron peak sources if log v(p) (Hz). 14.0, intermediate synchrotron peak sources if 14.0 < log v(p) (Hz) <= 15.3, and high synchrotron peak sources if log v(p) (Hz) > 15.3. (3) Gamma-ray emissions are strongly correlated with radio emissions. Gamma-ray luminosity is also correlated with synchrotron peak luminosity and integrated luminosity. (4) There is an anticorrelation between peak frequency and peak luminosity within the whole blazar sample. However, there is a marginally positive correlation for high synchrotron peak BL Lacs (HBLs), and no correlations for FSRQs or low synchrotron peak BL Lacs (LBLs). (5) There are anticorrelations between the monochromatic luminosities (gamma-ray and radio bands) and the peak frequency within the whole sample and BL Lacs. (6) The optical to X-ray (alpha OX) and radio to optical (alpha RO) spectral indices are strongly anticorrelated with peak frequency (log v(p)) within the whole sample, but the correlations for subclasses of FSRQs, LBLs, and HBLs are different.