What Powers the Most Relativistic Jets? I: BL Lacs

Abstract

The dramatic relativistic jets pointing directly at us in BL Lac objects can be well modelled by bulk motion beaming of synchrotron self-Compton emission powered by a low Eddington fraction accretion flow. Nearly 500 of these AGN are seen in the 2nd Fermi Large Area Telescope catalogue of AGN. We combine the jet models which describe individual spectra with the expected jet parameter scalings with mass and mass accretion rate to predict the expected number of Fermi detected sources given the number densities of AGN from cosmological simulations. We select only sources with Eddington scaled mass accretion rate $<0.01$ (i.e. radiatively inefficient flows), and include cooling, orientation effects, and the effects of absorption from pair production on the extragalactic IR background. These models overpredict the number of Fermi detected BL Lacs by a factor of 1000! This clearly shows that one of the underlying assumptions is incorrect, almost certainly that jets do not scale simply with mass and accretion rate. The most plausible additional parameter which can affect the region producing the Fermi emission is black hole spin. We can reproduce the observed numbers of BL Lacs if such relativistic jets are only produced by the highest spin ($a_{\ast }>0.8$) black holes, in agreement with the longstanding spin-jet paradigm. This also requires that high spins are intrinsically rare, as predicted by the cosmological simulations for growing black hole mass via chaotic (randomly aligned) accretion episodes, where only the most massive black holes have high spin due to black hole-black hole mergers.

10 pages, 6 figures; accepted for publication in MNRAS

References in corpus (37)

• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
• Towards a unified model for black hole X-ray binary jets
• Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991
• Fermi Large Area Telescope Second Source Catalog
• Modelling the behaviour of accretion flows in X-ray binaries
• A fundamental plane of black hole activity
• A Cosmology Calculator for the World Wide Web
• A Systematic Study of Radio-Induced X-ray Cavities in Clusters, Groups, and Galaxies
• AGN Black Hole Masses and Bolometric Luminosities
• A Scheme to Unify Low-Power Accreting Black Holes - Jet-Dominated Accretion Flows and the Radio/X-Ray Correlation
• On the fundamental dichotomy in the local radio-AGN population: accretion, evolution, and host galaxy properties
• General physical properties of bright Fermi blazars
• Radio-Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications
• Canonical high power blazars
• The Non-Linear Dependence of Flux on Black Hole Mass and Accretion Rate in Core Dominated Jets
• The distribution and cosmic evolution of massive black hole spins
• The transition between BL Lac objects and Flat Spectrum Radio Quasars
• The Formation and Evolution of Massive Black Holes
• The blazar sequence: a new perspective
• The Evolution of Black Hole Mass and Spin in Active Galactic Nuclei
• Grand unification of AGN activity in the LambdaCDM cosmology
• Spectroscopy of The Largest Ever Gamma-ray Selected BL Lac Sample
• TeV BL Lac objects at the dawn of the Fermi era
• Observational Evidence for a Correlation Between Jet Power and Black Hole Spin
• The evolution of AGN across cosmic time: what is downsizing?
• A Lower-Limit Flux for the Extragalactic Background Light
• Black-Hole Spin and Galactic Morphology
• Rapid variability in TeV blazars: the case of PKS 2155-304
• Magnetic flux paradigm for radio-loudness of AGN
• Observational constraints on the powering mechanism of transient relativistic jets
• Constraints on the role of synchrotron X-rays from jets of accreting black holes
• Observational constraints on the spin of the most massive black holes from radio observations
• The Link Between Star Formation and Accretion in LINERs: A Comparison with other AGN Subclasses
• A new connection between the opening angle and the large-scale morphology of extragalactic radio sources
• Is there really a dichotomy in AGN jet power?

Cited by in corpus (10)

• On The Efficiency of Jet Production in Radio Galaxies
• The Mass and Spin of The Extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and Its Implications for The Trigger for Relativistic Jets
• Disk-Jet Connection in Active Supermassive Black Holes in the Standard Accretion Disk Regime
• What Powers the Most Relativistic Jets? II: Flat Spectrum Radio Quasars
• The relativistic jet of the $\gamma$-ray emitting narrow-line Seyfert 1 galaxy PKS J1222$+$0413
• Cosmic Radio Background from Primordial Black Holes at Cosmic Dawn
• The distribution and lifetime of powerful radio galaxies as a function of environment and redshift
• Toy model for the acceleration of blazar jets
• The redshift distribution of BL Lacs and FSRQs
• Radio signals from early direct collapse black holes