General Physical Properties of CGRaBS Blazars

Abstract

We present the results of a multi-frequency, time-averaged analysis of blazars included in the Candidate Gamma-ray Blazar Survey catalog. Our sample consists of 324 γ-ray detected (γ-ray loud) and 191 non γ-ray detected (γ-ray quiet) blazars, and we consider all the data up to 2016 April 1. We find that both the γ-ray loud and the γ-ray quiet blazar populations occupy similar regions in the WISE color-color diagram, and in the radio and X-ray bands γ-ray loud sources are brighter. A simple one-zone synchrotron inverse-Compton emission model is applied to derive the physical properties of both populations. We find that the central black hole mass and the accretion disk luminosity (L disk ) computed from the modeling of the optical-UV emission with a Shakura-Sunyaev disk reasonably matches with that estimated from the optical spectroscopic emission-line information. A significantly larger Doppler boosting in the γ-ray loud blazars is noted, and their jets are more radiatively efficient. On the other hand, the γ-ray quiet objects are more MeV-peaked, thus could be potential targets for next-generation MeV missions. Our results confirm the earlier findings about the accretion-jet connection in blazars; however, many of the γ-ray quiet blazars tend to deviate from the recent claim that the jet power exceeds L disk in blazars. A broadband study, considering a larger set of γ-ray quiet objects and also including BL Lacs, will be needed to confirm/reject this hypothesis and also to verify the evolution of the powerful high-redshift blazars into their low-power nearby counterparts.

NuSTAR Perspective on High-redshift MeV Blazars

“…More recent results show that a positive correlation remains for γ-quiet sources (i.e. blazars not detected in γ-rays) beyond z = 3 (Paliya et al 2017a). However, as discussed above, having γ-ray data is crucial to accurately determine the jet power.…”

“…With a good IR-UV coverage, the uncertainty associated with this approach are of about a factor of 2 and the results have been shown to be in good agreement with the virial method (see e.g. Castignani et al 2013;Ghisellini & Tavecchio 2015;Paliya et al 2017a). The accretion disk spectral energy distribution is assumed to be a multi-color blackbody.…”

“…On another important note, the SED peaks' shift also reveals the underlying thermal emission from the accretion disk at optical-UV energies (e.g., , which can be modeled to extract the black-hole mass and the accretion disk luminosity (Shakura & Sunyaev 1973). This fact renders MeV blazars excellent probes for addressing open issues such as the accretion disk-jet connection in jetted quasars (e.g., Paliya et al 2017a), as well as the understanding of black hole growth and evolution in the early stages of the Universe (Volonteri et al 2011). Indeed, since the detection of a single source with jets aligned to our line of sight implies the existence of 2Γ 2 similar sources, at the same z, with same black hole masses but misaligned jets, finding more high-redshift blazars allows us to probe their intrinsic population and constrain the space density of supermassive black-holes (e.g., Sbarrato et al 2014).…”

Calibrating The Power Of Relativistic Jets

“…The smallest sample is Jorstad et al's [12], comprising 36 sources (21 quasars, 12 BL Lac objects, and 3 radio galaxies). The largest one is that of Paliya et al [18,19], made up of 531 sources, including 16 jetted narrow-line Seyfert 1 galaxies. When comparing two methods, we always select the subsample of sources in common between the two works.…”

“…The two samples have 99 sources in common. The datasets also differ with reference to high-energy γ-rays, which are the dominant quantity in determining the jet power, [9] and Paliya et al [18,19]. The dashed line is the 1 : 1 ratio.…”