The power and production efficiency of blazar jets

Abstract

We use published data on the power and production efficiency of jets in blazars with double radio lobes in order to compare results obtained using different methods. In order to eliminate selection effects, we use cross-matched sub-samples containing only luminous blazars. We compare the three main existing methods, namely those based on the emission of radio lobes, on spectral fitting, and on radio core shift. We find the average jet power obtained for identical samples with the radio-lobe method is ∼10 times lower than that from the spectral fitting. In turn, the power from spectral fitting is compatible with that from core-shift modelling for plausible parameters of the latter. We also consider a phenomenological estimator based on the γ-ray luminosity. We examine uncertainties of those methods and discuss two alternative hypotheses. In one, the blazar-fit and core-shift methods are assumed to be correct, and the lower power from radio lobes is caused by intermittency of accretion. Long periods of quiescence cause the energy in the radio lobes, accumulated over the lifetime of the blazar, to be much less than that estimated based on the present luminous state. In addition, the power calculated using the radio lobes can be underestimated for intrinsically compact jets, in which the radio core flux can be over-subtracted. In our second hypothesis, the radio-lobe method is assumed to be correct, and the blazar-fit and core-shift powers are reduced due to the presence of ∼15 pairs per proton and a larger magnetization than usually assumed, respectively.

NuSTAR Perspective on High-redshift MeV Blazars

“…However, we need to be cautious and take into account uncertainties in our measurements. For example, in our treatment we do not consider electron positron pairs, which, if present, would reduce the estimated jet power by a factor n e /n p (n e = n e + + n e − , see Pjanka et al 2017). Nevertheless, to avoid the Compton Rocket effect that would otherwise break the jet (see Ghisellini & Tavecchio 2010), the number of pairs could not outnumber by a large amount the number of protons.…”

General Physical Properties of CGRaBS Blazars

“…This assumption is crucial and often leads to the total jet power in powerful FSRQs to exceed L Edd (e.g., Ghisellini et al 2014). Considering the presence of the electron-positron pairs would reduce the budget of the jet power (see, e.g., Madejski et al 2016;Pjanka et al 2017 L disk γ-ray loud γ-ray quiet Figure 10. Distributions of various jet powers considering twosided jets.…”

Photohadronic scenario in interpreting the February–March 2014 flare of 1ES 1011+496

“…But the efficiency of the photohadronic process depends on the photon density in the blazar jet. In a normal jet, the photon density is low, which makes the process inefficient [20]. However, it is assumed that during the flaring the photon density in the inner jet region can go up so that the Δ-resonance production is moderately efficient.…”

“…Cao et al [18] have shown that the interaction of high energy protons with the synchrotron photons in the jet can produce γ -rays from π 0 decay and can explain the multi-TeV emission from 1ES 1011-232. Also Zdziarski et al [19,20] have used the hadronic model to explain the broad band spectra of radio-loud AGN. However, both the above scenarios require super Eddington luminosity in protons to explain the multi-TeV emission.…”