Spectroscopy of Broad-Line Blazars From 1lac

Shaw, M. S.; Romani, Roger W.; Cotter, Garret; Healey, S. E.; Michelson, P. F.; Readhead, A. C. S.; Richards, J. L.; Max-Moerbeck, W.; King, O. G.; Potter, William J.

doi:10.1088/0004-637x/748/1/49

Cited by 233 publications

(316 citation statements)

References 28 publications

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“…For this object, we found two black hole mass estimates, both based on the reverberation-mapping calibrated virial mass estimator, log(M BH /M ) = 8.17 (Wang et al 2004), based on Hβ line width and extrapolated continuum luminosity, and two values, log(M BH /M ) = 8.91 ± 0.29 and log(M BH /M ) = 8.89 ± 0.15, based on Mg II and Hβ lines, respectively (Shaw et al 2012). Here we adopt a more recent estimate of Shaw et al (2012), conservatively taking log(M BH /M ) = 8.9 ± 0.3. Mrk 421.…”

Section: Smbh Masses and Corresponding Time Scalesmentioning

confidence: 89%

Minimal variability time scale – central black hole mass relation of theγ-ray loud blazars

Vovk

Babić

2015

A&A

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Context. The variability time scales of the blazar γ-ray emission contain the imprints of the sizes of their emission zones and are generally expected to be larger than the light-crossing times of these zones. In several cases the time scales were found to be as short ∼10 min, suggesting that the emission zone sizes are comparable with the sizes of the central supermassive black holes. Previously, these measurements also led to the suggestion of a possible connection between the observed minimal variability time scales and the masses of the corresponding black holes. This connection can be used to determine the location of the γ-ray emission site, which currently remains uncertain. Aims. The study aims to investigate the suggested "minimum time scale -black hole mass" relation using the blazars, detected in the TeV band. Methods. To obtain the tightest constraints on the variability time scales this work uses a compilation of observations by the Cherenkov telescopes HESS, MAGIC, and VERITAS. These measurements are compared to the blazar central black hole masses found in the literature.Results. The majority of the studied blazars show the variability time scales which are at least comparable to the period of rotation along the last stable orbit of the central black hole -and in some cases as short as its light-crossing time. For several sources the observed variability time scales are found to be smaller than the black hole light-crossing time. This suggests that the detected γ-ray variability originates, most probably, from the turbulence in the jet, sufficiently far from the central black hole.

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Section: Smbh Masses and Corresponding Time Scalesmentioning

confidence: 89%

Minimal variability time scale – central black hole mass relation of theγ-ray loud blazars

Vovk

Babić

2015

A&A

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“…Our sample is composed by 229 blazars detected by Fermi/LAT 31,33 for which broad emission lines have been measured 12,13,32 . This sample does not include several bright and famous blazars with historical spectroscopic classifications in the literature.…”

Section: Methodsmentioning

confidence: 99%

The power of relativistic jets is larger than the luminosity of their accretion disks

Ghisellini

Tavecchio

Maraschi

et al. 2014

Nature

437

521

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Theoretical models for the production of relativistic jets from active galactic nuclei predict that jet power arises from the spin and mass of the central black hole, as well as the magnetic field near the event horizon 1 . The physical mechanism mechanism underlying the contribution from the magnetic field is the torque exerted on the rotating black hole by the field amplified by the accreting material. If the squared magnetic field is proportional to the accretion rate, then there will be a correlation between jet power and accretion luminosity. There is evidence for such a correlation 2-8 , but inadequate knowledge of the accretion luminosity of the limited and inhomogeneous used samples prevented a firm conclusion. Here we report an analysis of archival observations of a sample of blazars (quasars whose jets point towards Earth) that overcomes previous limitations. We find a clear correlation between jet power as measured through the γ-ray luminosity, and accretion luminosity as measured by the broad emission lines, with the jet power dominating over the disk luminosity, in agreement with numerical simulations 9 . This implies that the magnetic field threading the black hole horizon reaches the maximum value sustainable by the accreting matter 10 .The jet power is predicted 1 to depend on (aMB) 2 , where a and M are respectively the spin and mass of the black hole and B is the magnetic field at its horizon. Seed magnetic fields are amplified by the accretion disk up to equipartition with the mass energy density ∼ ρc 2 of the matter accreting at the rateṀ . A greaterṀ implies a larger ρ, that can sustain a larger magnetic field, which in turn can tap a larger amount of the black hole rotational energy. The magnetic field is thus a catalyst for the process. Increasing the spin of the black hole shrinks the innermost stable orbit, increasing the accretion efficiency η (defined by η = L disk /Ṁc 2 ) (L disk accretion disk luminosity) to a maximum value 11 η = 0.3.We use a well designed sample of blazars that have been detected in the γ-ray band by the Fermi Large Area Telescope (LAT) that have been spectroscopically observed in the optical 12, 13 (see Methods). They have been classified as BL Lac objects or Flat Spectrum Radio Quasars (FSRQs) according if the rest frame equivalent width of their broad emission lines was greater (FSRQ) or smaller (BL Lacs) than 5Å (rest frame). The sample contains 229 FSRQs, and 475 BL Lacs. Of the latter, 209 have a spectroscopically measured redshift. We considered all FSRQs with enough multi-wavelength data to have a Spectral Energy Distribution (SED) that allows to establish the bolometric luminosity. The considered FSRQs amount to 191 objects. Instead, for BL Lacs, we consider only the 26 sources with detected broad emission lines. This makes them the low disk luminosity tail of of the full 1 blazar sample. This choice is dictated by our will to measure the accretion luminosity, together with the jet power. Through the visible broad emission lines we reconstruct, through a t...

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“…Its optical spectrum was described by Shaw et al (2012) as transitional between flat-spectrum quasars and BL Lac type objects. It was detected by Fermi with a statistical significance of 52.1σ, corresponding to 3FGL J2236.3+2829 and 2FGL J2236.4+2828 (Acero et al, 2015), but not detected by the Energetic Gamma Ray Experiment Telescope (EGRET; Hartman et al, 1999) of the Compton Gamma Ray Observatory, probably due to insufficient sensitivity.…”

Section: Cso Identification Of 2234+282mentioning

confidence: 99%

Radio properties of the γ ‐ray emitting CSO candidate 2234+282

Cui

Gabányi

et al. 2016

Astron Nachr

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Most of the γ-ray emitting active galactic nuclei (AGN) are blazars, although there is still a small fraction of non-blazar AGN in the Fermi/LAT catalog. Among these misaligned γ-ray-emitting AGN, a few can be classified as Compact Symmetric Objects (CSOs). In contrast to blazars in which γ-ray emission is generally thought to originate from highly beamed relativistic jets, the source of γ-ray emission in unbeamed CSOs remains an open question. The rarity of the γ-ray emitting CSOs is a mystery as well. Here we present the radio properties of the γ-ray CSO candidate 2234+282.

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Spectroscopy of Broad-Line Blazars From 1lac

Cited by 233 publications

References 28 publications

Minimal variability time scale – central black hole mass relation of theγ-ray loud blazars

Minimal variability time scale – central black hole mass relation of theγ-ray loud blazars

The power of relativistic jets is larger than the luminosity of their accretion disks

Radio properties of the γ ‐ray emitting CSO candidate 2234+282

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