CONSTRAINTS ON THE MINIMUM ELECTRON LORENTZ FACTOR AND MATTER CONTENT OF JETS FOR A SAMPLE OF BRIGHT FERMI BLAZARS

Abstract

We fit the (quasi-)simultaneous multi-waveband spectral energy distributions (SEDs) for a sample of low-synchrotron-peaked (LSP) blazars with a one-zone leptonic model. The seed photons that predominantly come from broad line region (BLR) and infrared (IR) molecular torus are considered respectively in external Compton process. We find that the modeling with IR seed photons is systematically better than that with BLR photons based on a χ 2 test, which suggest that γ-ray emitting region most possibly stay outside the BLR. The minimum electron Lorentz factor, γ min , is constrained from the modeling for these LSP blazars with good soft X-ray data (ranges from 5 to 160 with a median value of 55), which plays a key role in jet power estimation. Assuming one-to-one ratio of proton and electron, we find that the jet power for LSP blazars is systematically higher than that of FR II radio galaxies at given 151 MHz radio luminosity, L 151MHz , even though FR IIs are regarded as same as LSP blazars in unification scheme except the jet viewing angle. The possible reason is that there are some e ± pairs in the jet of these blazars. If this is the case, we find the number density of e ± pairs should be several times higher than that of e − − p pairs by assuming the jet power is the same for LSP blazars and FR IIs at given L 151MHz .

CONSTRAINING THE PHYSICAL CONDITIONS IN THE JETS OF Γ-Ray FLARING BLAZARS USING CENTIMETER-BAND POLARIMETRY AND RADIATIVE TRANSFER SIMULATIONS. II. EXPLORING PARAMETER SPACE AND IMPLICATIONS

“…Of course, that means that in those cases the precise value is ill-constrained, as at these high values changes in the cutoff value lead to very small changes in the light curves, but that does not invalidate the general conclusion that these flows do not have particle energy spectra extending far below the energy responsible for the centimeter-band emission. The values found in this analysis are in agreement with the range of values found by Kang et al (2014) (from 5 to 160, with a median of 55).…”

On the Origin of the Hard X-Ray Excess of High-Synchrotron-Peaked BL Lac Object Mrk 421

“…For the model description, see the Appendix for detail (see also Chen et al 2012;Kang et al 2014). During our modeling, the Doppler beaming factor is assumed to be same as that in Baloković et al (2016), i.e., δ = 25.…”

“…These lowest-energy electrons will IC scatter the soft seed photons and emit at the X-ray band. Therefore, careful SED modeling (especially modeling the IC X-ray spectra) is widely used to estimate the minimal electron energy and furthermore to calculate, for example, the jet power (see, e.g., Celotti & Ghisellini 2008;Chen et al 2010;Kang et al 2014;Ghisellini et al 2014). …”

On the origin of the soft photons of the high-synchrotron-peaked blazar PKS 1424+240

“…In order to minimize hardening introduced from EBL absorption corrections, we adopt the absorption optical depth that derived from the EBL model proposed by Domínguez et al (2011) in our calculations. In our SED modeling of Figure 1, we assume the model prediction as the intrinsic emission and correct it to our local universe using equation (2), and compare it with the observational data (e.g., Zheng & Zhang 2011;Zheng et al , 2014Kang et al 2014). …”