J/ApJ/859/116 BH masses and Eddington ratios of Type 2 QSOs (Kong+, 2018)
The black hole masses and Eddington ratios of type 2 quasars.
Kong M., Ho L.C.
<Astrophys. J., 859, 116 (2018)>
=2018ApJ...859..116K 2018ApJ...859..116K
ADC_Keywords: QSOs; Spectra, optical; Redshifts; Velocity dispersion;
Active gal. nuclei; Equivalent widths
Keywords: galaxies: active ; galaxies: nuclei ; galaxies: Seyfert ;
quasars: emission lines
Abstract:
Type 2 quasars are an important constituent of active galaxies,
possibly representing the evolutionary precursors of traditionally
studied type 1 quasars. We characterize the black hole (BH) mass (MBH)
and Eddington ratio (Lbol/LEdd) for 669 type 2 quasars selected from
the Sloan Digital Sky Survey, using BH masses estimated from the
MBH-σ* relation and bolometric corrections scaled from the
extinction-corrected [OIII]λ5007 luminosity. When stellar
velocity dispersions cannot be measured directly from the spectra, we
estimate them from the core velocity dispersions of the narrow
emission lines [OII]λλ3726,3729,
[SII]λλ6716,6731, and [OIII]λ5007, which are
shown to trace the gravitational potential of the stars. Energy input
from the active nucleus still imparts significant perturbations to the
gas kinematics, especially to high-velocity, blueshifted wings.
Nonvirial motions in the gas become most noticeable in systems with
high Eddington ratios. The BH masses of our sample of type 2 quasars
range from MBH∼106.5 to 1010.4M☉ (median 108.2M☉).
Type 2 quasars have characteristically large Eddington ratios
(Lbol/LEdd∼10-2.9-101.8; median 10-0.7), slightly higher than in
type 1 quasars of similar redshift; the luminosities of ∼20% of the
sample formally exceed the Eddington limit. The high Eddington ratios
may be consistent with the notion that obscured quasars evolve into
unobscured quasars.
Description:
We focus on the sample of 887 type 2 quasars with redshifts
0.037<z<0.83 from Reyes+ (2008, J/AJ/136/2373).
We obtain the optical spectra of the sample from the seventh data
release of SDSS (Abazajian+ 2009, II/294).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 173 887 Sample Properties
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJS/112/315 : Spectroscopic parameters of Seyfert nuclei (Ho+ 1997)
J/AJ/126/2125 : SDSS candidate type II quasars (Zakamska+, 2003)
J/ApJS/152/251 : Indo-US library of coude feed stellar sp. (Valdes+, 2004)
J/MNRAS/371/703 : MILES library of empirical spectra (Sanchez-Blazquez+, 2006)
J/AJ/136/2373 : Type 2 quasars from SDSS (Reyes+, 2008)
J/ApJ/702/441 : Obscured active galaxies (Greene+, 2009)
J/ApJS/183/1 : Catalog of central stellar velocity dispersions (Ho+, 2009)
J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/MNRAS/426/2703 : Type 1 AGN at low z. II. (Stern+, 2012)
J/MNRAS/435/3306 : Candidate type II QSOs in SDSS III (Alexandroff+, 2013)
J/ApJ/805/96 : SDSS-RM project: velocity dispersions of QSOs (Shen+, 2015)
J/MNRAS/455/4191 : Radio emission from radio-quiet quasars (Zakamska+, 2016)
J/ApJ/835/223 : A catalog of nearby galaxies with Chandra obs. (She+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS Object Name (JHHMMSS.ss+DDMMSS.s)
21- 21 A1 --- flag a=Kinematically complex emission-line core
23- 28 F6.4 --- zspec [0.03/0.9] SDSS spectroscopic redshift
30- 35 F6.4 mag Av [0.01/0.7] Extinction in the V band
37- 40 F4.1 --- S/N [0/36] Average S/N per pixel over
the region 4400-4600Å
42- 42 A1 --- l_EW Limit flag on EW
44- 47 F4.1 0.1nm EW [3/12.5] Equivalent width of the G band
49- 53 F5.2 --- Ha/Hb [3/12]? Observed Balmer decrement,
Hα/Hβ (1)
55- 58 F4.2 --- e_Ha/Hb [0.03/1.2]? Uncertainty in Ha/Hb
60- 64 F5.2 [10-7W] logL[OIII] [41.7/44.5] log of extinction-corrected
luminosity of [OIII]5007Å (2)
66- 69 F4.2 [10-7W] e_logL[OIII] [0.01/0.4] Uncertainty in logL[OIII]
71- 75 F5.1 km/s sigma [69/620]? Stellar velocity dispersion
(σ*)
77- 81 F5.1 km/s e_sigma [8/159]? Uncertainty in sigma
83- 87 F5.1 km/s sig[SII]c [58/402]? Gaseous velocity dispersion,
core component of [SII]6716Å,6731Å
89- 92 F4.1 km/s e_sig[SII]c [0.6/79]? Uncertainty in sig[SII]c
94- 98 F5.1 km/s sig[OII]c [46/468]? Gaseous velocity dispersion,
core component of [OII]3726Å,3729Å
100-103 F4.1 km/s e_sig[OII]c [1/98]? Uncertainty in sig[OII]c
105-109 F5.1 km/s sig[OIII]c [50/728.5]? Gaseous velocity dispersion,
core component of [OIII]5007Å
111-115 F5.1 km/s e_sig[OIII]c [0.1/214]? Uncertainty in sig[OIII]c
117-121 F5.1 km/s sig[SII]s [98/770]? Second moment of the line
profile, [SII]6716Å,6731Å
123-126 F4.1 km/s e_sig[SII]s [0.8/98]? Uncertainty in sig[SII]s
128-132 F5.1 km/s sig[OII]s [98/835]? Second moment of the line
profile, [OII]3726Å,3729Å
134-138 F5.1 km/s e_sig[OII]s [1/189]? Uncertainty in sig[OII]s
140-145 F6.1 km/s sig[OIII]s [87/1050]? Second moment of the line
profile, [OIII]5007Å
147-151 F5.1 km/s e_sig[OIII]s [0.8/194]? Uncertainty in sig[OIII]s
153-157 F5.2 [Msun] logMBH [6.4/10.4]? log of black hole mass (3)
159-162 F4.2 [Msun] e_logMBH [0.3/0.9]? Uncertainty in logMBH
164-168 F5.2 --- Lbol/LEdd [-3/1.8]? Eddington ratio calculated
with logL[OIII] (4)
170-173 F4.2 --- e_Lbol/LEdd [0.3/0.9]? Uncertainty in Lbol/LEdd
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Note (1): Observed Balmer decrement used to estimate internal extinction.
Objects for which the Balmer decrement could not be reliably determined
are assigned a value of Hα/Hβ=4.04, the median of the
detected objects.
Note (2): Extinction-corrected luminosity of [OIII]5007Å. The
uncertainties include measurement error and uncertainties of the Balmer
decrement.
Note (3): BH mass estimated from the MBH-σ* relation of Kormendy &
Ho (2013ARA&A..51..511K 2013ARA&A..51..511K ; Equation 2), using, in the order of preference,
σ*, σ[SII]c, σ[OII]c and σ[OIII]c with
σgc statistically corrected as described in Section 4.3.
Note (4): Eddington ratio calculated with extinction-corrected [OIII]
luminosity (logL[OIII]) and BH mass (logMBH). Uncertainties introduced
by the bolometric correction are included in the error budget.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Jun-2019