Multiepoch Multiwavelength Spectra and Models for Blazar 3C 279

Abstract

Of the blazars detected by EGRET in GeV γ rays, 3C 279 is not only the best-observed by EGRET, but also one of the best-monitored at lower frequencies. We have assembled eleven spectra, from GHz radio through GeV γ rays, from the time intervals of EGRET observations. Although some of the data have appeared in previous publications, most are new, including data taken during the high states in early 1999 and early 2000. All of the spectra show substantial γ-ray contribution to the total luminosity of the object; in a high state, the γ-ray luminosity dominates over that at all other frequencies by a factor of more than 10. There is no clear pattern of time correlation; different bands do not always rise and fall together, even in the optical, X-ray, and γ-ray bands.The spectra are modeled using a leptonic jet, with combined synchrotron self-Compton + external Compton γ-ray production. Spectral variability of 3C 279 is consistent with variations of the bulk Lorentz factor of the jet, accompanied by changes in the spectral shape of the electron distribution. Our modeling results are consistent with the UV spectrum of 3C 279 being dominated by accretion disk radiation during times of low γ-ray intensity.Subject headings: quasars: individual (3C 279)

Modelling the multi-wavelength emission of flat-spectrum radio quasar 3C 279

“…Now that scattered accretion disk emission (e.g. Hartman et al 2001;Dermer & Schlickeiser 2002) provides a similar emission component with IR emission, we argue that it is important to determine if the γ-ray emission region is made deep within the BLR or farther out, where the density of BLR is more dilute. We leave this open issue to the studies on γγ attenuation at very high energy γ-ray regime (e.g.…”

“…Multi-wavelength snapshot observations for several epoches including γ-rays show that the SED could be explained by the leptonic model (Hartman et al 2001). In order to comprehend intensively the energy spectrum character of the source, a multi-wavelength quasisimultaneous observation campaign has been organized by Hayashida et al (2012).…”

Radio-optical-gamma-ray properties of MOJAVE AGN detected byFermi/LAT

“…For low-frequency-peaked BL Lacs (LBLs) and flatspectrum radio quasars (FSRQs), it is generally accepted that leptonic models require external photon sources for Compton scattering (EC = External Compton) to produce the γ-ray emission (e.g., Dermer et al 1997;Sambruna et al 1997;Mukherjee et al 1999;Madejski et al 1999;Böttcher & Bloom 2000;Hartman et al 2001). In the case of quasars, the most prominent external radiation field might be the quasi-isotropic radiation field of the broad-line region (BLR), as long as the emission region is located within the BLR.…”

Signature of inverse Compton emission from blazars

“…The high energy spectrum of FSRQs thus contains a prominent contribution from EC processes (e.g. Mukherjee et al 1999;Hartman et al 2001) while that of HSPs can be sufficiently fit with SSC models (Pian et al 1998;Bottcher et al 2002). The ISPs and LSP BL Lacs being intermediate between these classes then require to account for a non-neglible contribution from EC processes to reproduce the high energy spectrum (Madejski et al 1999;Bottcher & Bloom 2000).…”