J/MNRAS/495/981 Jet efficiencies and black hole spins in quasars (Soares+, 2020)
Jet efficiencies and black hole spins in jetted quasars.
Soares G., Nemmen R.
<Mon. Not. R. Astron. Soc., 495, 981-991 (2020)>
=2020MNRAS.495..981S 2020MNRAS.495..981S (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Black holes ; Accretion ; Gamma rays ;
Redshifts
Keywords: accretion, accretion discs - black hole physics - galaxies: active -
galaxies: jets - gamma-rays: general
Abstract:
The mechanisms responsible for the production of relativistic jets
from supermassive black holes (SMBHs) accreting at near-Eddington
rates are not well understood. Simple theoretical expectations
indicate that SMBHs in quasars accrete via thin discs which should
produce at most very weak jets. This is contradicted by observations
of powerful jets in flat-spectrum radio quasars (FSRQs). We use
gamma-ray luminosities observed with the Fermi Large Area Telescope as
a proxy of the jet power for a population of 154 FSRQs. Assuming
typical quasar accretion rates and using black hole (BH) mass
measurements from a variety of methods, we find a mean jet production
efficiency of about 10 per cent for FSRQs, with values as high as 222
per cent. We find that this is consistent with FSRQs hosting
moderately thin, magnetically arrested accretion discs around rapidly
spinning BHs. Modelling our observations using general relativistic
magnetohydrodynamic (GRMHD) simulations of jets from thin discs, we
find an average lower limit of a*=0.59 for the SMBH spins of FSRQs,
with tendency for the spins to decrease as the BH mass increases. Our
results are consistent with the merger-driven evolution of SMBHs. 3
per cent of the sample cannot be explained by current GRMHD models of
jet production from Kerr BHs due to the high efficiencies. Along the
way, we find a correlation between BH masses and Lγ which may
be an useful mass estimator in blazar gamma-ray studies.
Description:
For our study, we need a sample of jetted quasars with estimated jet
powers and BH masses. This sample was provided by Ghisellini et al.
(2014Natur.515..376G 2014Natur.515..376G, Cat. J/other/Nat/515.376) and Ghisellini &
Tavecchio (2015MNRAS.448.1060G 2015MNRAS.448.1060G, Cat. J/MNRAS/448/1060), hereafter G14
and G15, respectively.
G14 and G15 published a sample of blazars that have been detected in
gamma-rays by Fermi-LAT and spectroscopically observed in the optical
band (Shaw et al. 2012ApJ...748...49S 2012ApJ...748...49S, Cat. J/ApJ/748/49; Shaw et al.
2013ApJ...764..135S 2013ApJ...764..135S, Cat. J/ApJ/764/135), including 229 FSRQs and 475
BL Lacs. The Ghisellini sample is based on the first and second
Fermi-LAT catalogues, corresponding to only 2yr of gamma-ray
observations. We have now more than 10yr of LAT observations,
therefore we cross-matched the original sample of FSRQs from G14 and
G15 with the most up-to-date catalogue of LAT sources - 4FGL; The
Fermi-LAT collaboration (2020ApJS..247...33A 2020ApJS..247...33A, Cat. J/ApJS/247/33) -
ending up with 191 FSRQs.
We were able to identify 156 objects in the Fermi 4FGL catalogue, out
of the 191 sources in G15. Still, the objects 1438+3710 and 1439+3712
in G15 were both associated with 4FGL J1438.9+3710 by our distance
method. Similarly, the objects 1636+4715 and 1637+4717 were both
associated with 4FGL J1637.7+4717. Given their significantly different
redshifts, we searched the literature and the 4FGL and G15 aliases to
determine which object should be correctly associated with both 4FGL
sources, and we determined that both 1439+3712 and 1636+4715 should be
excluded from our analysis. Hence, our final sample contains 154
objects. Table A1 lists the FSRQs names, coordinates along with the
other relevant properties for this work such as their gamma-ray
luminosities and BH masses.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 78 154 Data on the objects used in this work
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See also:
J/other/Nat/515.376 : Power of relativistic jets in blazars
(Ghisellini+, 2014)
J/MNRAS/448/1060 : Fermi/LAT broad emission line blazars
(Ghisellini+, 2015)
J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL)
(Abdollahi+, 2020)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Source name (4FGL JHHMM.m+DDMM)
19- 27 A9 --- OName Alternative name (HHMM+DDMM) (1)
29- 33 F5.3 --- z Redshift
35- 38 F4.2 [Msun] logM Logarithm of the black hole mass (2)
40- 44 F5.2 [10-7W] logLgam Logarithm of the Fermi-LAT gamma-ray flux
Lγ
46- 50 F5.2 [10-7W] logPjet Logarithm of the total jet power of blazars
(3)
52- 56 F5.3 --- eta Efficiency of jet production (4)
58- 62 F5.3 --- b_eta Jet efficiency lower limit
64- 68 F5.3 --- spin ? Dimensionless black hole spin
70 A1 --- f_spin Flag on spin (5)
72- 76 F5.3 --- b_spin ? Spin lower limit
78 A1 --- fbspin Flag on b_spin (6)
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Note (1): Alternative name from Ghisellini et al. (2014Natur.515..376G 2014Natur.515..376G,
Cat. J/other/Nat/515.376) or Ghisellini & Tavecchio
(2015MNRAS.448.1060G 2015MNRAS.448.1060G, Cat. J/MNRAS/448/1060)
Note (2): The uncertainty in mass is 0.5dex
Note (3): Nemmen et al. (2012Sci...338.1445N 2012Sci...338.1445N, Cat. J/other/Sci/338.1445)
obtained a tight correlation between Lγ and the total jet
power of blazars:
log10Pjet=(0.51±0.02)log10Lγ+(21.2±1.1)
The uncertainty in jet power is 0.5dex
Note (4): The efficiency of jet production is defined as
η=Pjet/(dM/dtc2), where dM/dt is the mass accretion rate.
Here we take dM/dt=LEdd/c2, where LEdd is the Eddington
luminosity.
Note (5): Flag as follows:
* = Spin could not be obtained using the jet efficiency η as input to
the simulation-based model in equation 6 of the article
Note (6): Flag as follows:
* = Minimum spin could not be obtained using equation 6 of the article for
the minimum jet efficiency as input
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 08-Jun-2023