Study on the Curvature Properties of Spectral Energy Distribution for Fermi Blazars
Abstract
We collect 172 clean Fermi blazars with broadband quasi-simultaneous spectral data from radio to γ-ray. Both spectral energy distributions (SEDs) of synchrotron and inverse Compton (IC) components are fitted by a log-parabolic law in lg ν-lg ν fν diagram. The second-degree term of log-parabolic measures the curvature of SED. Our main intent is to explore the curvature properties of spectral energy distribution of Fermi blazars. Our main results are as follows: a significant correlation between the synchrotron peak frequency and its curvature for flat spectrum radio quasars (FSRQs) and BL Lacertae objects (BL Lacs) is found, but the correlation formulas are different for FSRQs and BL Lacs. Comparing our observational results and the theoretical predictions of different models, we find that the observational results of FSRQs are consistent with the fluctuation of fractional acceleration gain model, while the observational results of BL Lacs are consistent with the energy-dependent acceleration probability model. The mean value of synchrotron curvature of FSRQs is larger than that of BL Lacs, which suggests the particle acceleration efficiency of BL Lacs is higher than that of FSRQs. It should be attributed to the jet plasma of FSRQs dissipated within the broad-line region (BLR) and suffered stronger cooling. We also find that FSRQs and Low-energy peaked BL Lacs (LBLs) have similar SED properties, which is consistent with previous results. We do not find a significant correlation between the IC peak frequency and its curvature for FSRQs and BL Lacs, which may be caused by complicated seed photon field and radiation processes.
- Publication:
-
Acta Astronomica Sinica
- Pub Date:
- November 2017
- Bibcode:
- 2017AcASn..58...57L
- Keywords:
-
- galaxies: active galaxies;
- radiation mechanisms: non-thermal;
- methods: Statistical