J/ApJ/962/152 QSOs at z∼4 from Subaru/HSC wide field & BH masses (He+, 2024)
Black hole mass and Eddington-ratio distributions of less-luminous quasars at
z∼4 in the Subaru Hyper Suprime-Cam Wide Field.
He W., Akiyama M., Enoki M., Ichikawa K., Inayoshi K., Kashikawa N.,
Kawaguchi T., Matsuoka Y., Nagao T., Onoue M., Oogi T., Schulze A.,
Toba Y., Ueda Y.
<Astrophys. J., 962, 152 (2024)>
=2024ApJ...962..152H 2024ApJ...962..152H
ADC_Keywords: QSOs; Black holes; Spectra, optical; Redshifts
Keywords: Supermassive black holes ; Galaxy evolution ; High-redshift galaxies ;
Active galaxies
Abstract:
We investigate the black hole mass function (BHMF) and Eddington-ratio
distribution function (ERDF) of broad-line active galactic nuclei
(AGNs) at z=4, based on a sample of 52 quasars with i<23.2 at
3.50≤z≤4.25 from the Hyper Suprime-Cam Subaru Strategic Program
S16A-Wide2 data set, and 1462 quasars with i<20.2 in the same redshift
range from the Sloan Digital Sky Survey data release 7 quasar catalog.
Virial black hole (BH) masses of quasars are estimated using the width
of the CIV 1549Å line and the continuum luminosity at 1350Å. To
obtain the intrinsic broad-line AGN BHMF and ERDF, we correct for the
incompleteness in the low-mass and/or low-Eddington-ratio ranges
caused by the flux-limited selection. The resulting BHMF is
constrained down to logMBH/M☉∼7.5. In comparison with
broad-line AGN BHMFs at z∼2 in the literature, we find that the number
density of massive SMBHs peaks at higher redshifts, consistent with
the downsizing evolutionary scenario. Additionally, the resulting ERDF
shows a negative dependence on BH mass, suggesting more massive SMBHs
tend to accrete at lower-Eddington ratios at z=4. With the derived
intrinsic broad-line AGN BHMF, we also evaluate the active fraction of
broad-line AGNs among the entire SMBH population at z=4. The resulting
active fraction may suggest a positive dependence on BH mass. Finally,
we examine the time evolution of broad-line AGN BHMF between z=4 and 6
through solving the continuity equation. The results suggest that the
broad-line AGN BHMFs at z=4-6 only show evolution in their
normalization, but with no significant changes in their shape.
Description:
We use the sample of less-luminous z∼4 quasar candidates constructed
with the HSC-SSP S16A-Wide2 data set (for details see
Akiyama+ 2018PASJ...70S..34A 2018PASJ...70S..34A). See Section 2.1.
We carried out spectroscopic observations of the z∼4 quasar candidates
using the two-degree field (2dF) fiber positioner with the AAOmega
spectrograph mounted on the 3.9m Anglo-Australian Telescope (AAT)
during three observing runs S17A/08, S18A/16, and S18B/03 between 2017
and 2019, and the DEep Imaging Multi-Object Spectrograph (DEIMOS)
mounted on the Keck II telescope during the observing run S356 in 2019.
See Section 2.2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 64 151 Identified 3<z<4.5 quasars
table7.dat 99 80 Continuum and emission line properties of the
80 quasars with quality flag QOP=4
--------------------------------------------------------------------------------
See also:
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)
J/ApJ/666/806 : SED of Spitzer quasars (QUEST) (Netzer+, 2007)
J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)
J/ApJ/680/169 : SDSS DR5 virial black hole masses (Shen+, 2008)
J/ApJ/690/20 : Models of the AGN & black hole populations (Shankar+, 2009)
J/ApJ/708/137 : Broad-line AGNs in zCOSMOS survey (Merloni+, 2010)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/MNRAS/427/3103 : COSMOS field supermassive black holes (Bongiorno+, 2012)
J/ApJ/761/143 : Black hole masses of z∼1.4 AGNs from SXDS (Nobuta+, 2012)
J/ApJ/746/169 : Luminosity function of broad-line quasars (Shen+, 2012)
J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)
J/A+A/556/A55 : Multi-color phot. of star-forming galaxies (Ilbert+, 2013)
J/ApJ/764/45 : Luminosity function of broad-line QSOs. II. (Kelly+, 2013)
J/ApJ/773/14 : BOSS: quasar luminosity function (Ross+, 2013)
J/PASJ/65/113 : 0.006≤z≤0.8 IR galaxies with AKARI (Toba+, 2013)
J/ApJ/788/45 : Luminosity & redshift of gal. from WISE/SDSS (Toba+, 2014)
J/ApJ/813/82 : z<0.06 broad-line AGN emission-line measures (Reines+, 2015)
J/ApJ/815/129 : X-ray AGNs with Subaru/FMOS NIR observations (Suh+, 2015)
J/MNRAS/465/2120 : Correcting CIV-based virial BH masses (Coatman+, 2017)
J/AJ/155/131 : z∼5 QSO luminosity function from the CFHTLS (McGreer+, 2018)
J/PASJ/70/S10 : GOLDRUSH I. UV magnitudes (Ono+, 2018)
J/ApJS/239/22 : NIR obs. of AGNs in COSMOS, SXDS & E-CDF-S (Schulze+, 2018)
J/ApJ/873/35 : Gemini GNIRS NIR sp. of 50 QSOs at z≳5.7 (Shen+, 2019)
J/ApJ/941/106 : X-SHOOTER/ALMA QSOs at 5.7≲z≲7.6. II. (Farina+, 2022)
J/ApJ/941/97 : Opt-NIR phot. in HSC-deep XMM-LSS (Vijarnwannaluk+, 2022)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name Object identifier (JHHMMSS.ss+DDMMSS.ss)
22- 27 F6.2 deg RAdeg [32.7/342.6] Right ascension (J2000)
29- 33 F5.2 deg DEdeg [-6.8/43.1] Declination (J2000)
35- 46 A12 --- Selec Selection criteria (1)
48- 48 I1 --- QOP [3/4] Quality flag (2)
50- 52 A3 --- Type BAL=Broad Absorption Line quasar (11 occurrences)
54- 58 F5.2 mag imag [18.94/23.85] Apparent Subaru/HSC i-band AB
magnitude
60- 64 F5.3 --- z [3/4.5] Spectroscopic redshift
--------------------------------------------------------------------------------
Note (1): Selection criteria as follows:
collaborator = Quasars selected by Lyman break color or radio detection
(14 occurrences)
c1 = Equations (1)-(5) (92 occurrences)
c2 = 0.73(g-r)+0.009>(r-z) (i-z)>-0.3 (10 occurrences)
c3 = 0.51<(g-r)<1.50,0.76(g-r)-0.29>(r-z),(i-z)>-0.3,exclude c1
(26 occurrences)
c4 = 0.32<(g-r)<0.51,(r-z)<0.17 (6 occurrences)
c5 = 0.51<(g-r)<1.50,0.76(g-r)-0.10>(r-z),0.76(g-r)-0.29<(r-z),
Equations (4)-(5) (3 occurrences)
Note (2): Quality flag as follows:
4 = Both Lyman alpha and CIV emission lines detected and CIV line
profile detected with sufficient SNR;
3 = Only Lyman alpha emission line detected and CIV emission line highly
affected by absorption lines or barely detected such that its profile
cannot be well constrained.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name Object identifier (JHHMMSS.ss+DDMMSS.ss) (1)
22- 26 F5.2 [10-7W] logL1350 [41.7/43.3] Log of monochromic luminosity
at 1350Å; erg/s (2)
28- 31 F4.2 [10-7W] E_logL1350 [0/0.2] Upper uncertainty in logL1350
33- 36 F4.2 [10-7W] e_logL1350 [0/0.3] Lower uncertainty in logL1350
38- 42 I5 km/s FWHM [952/10902] Full-width at half-maximum of
CIV1549 emission line
44- 47 I4 km/s E_FWHM [28/5626] Upper uncertainty in FWHM
49- 52 I4 km/s e_FWHM [10/2907] Lower uncertainty in FWHM
54- 58 F5.2 [10-7W] logLbol [45.4/47] Log of bolometric luminosity;
erg/s
60- 63 F4.2 [10-7W] E_logLbol [0/0.2] Upper uncertainty in logLbol
65- 68 F4.2 [10-7W] e_logLbol [0/0.3] Lower uncertainty in logLbol
70- 73 F4.2 [Msun] logMbh [7.31/9.73] Log of supermassive black hole
virial mass
75- 78 F4.2 [Msun] E_logMbh [0.02/0.8] Upper uncertainty in logMbh
80- 83 F4.2 [Msun] e_logMbh [0.01/1.7] Lower uncertainty in logMbh
85- 89 F5.2 --- logEdd [-1.38/0.5] Log of ratio of bolometric to
Eddington luminosity
91- 94 F4.2 --- E_logEdd [0.01/1.65] Upper uncertainty in logEdd
96- 99 F4.2 --- e_logEdd [0.02/0.8] Lower uncertainty in logEdd
--------------------------------------------------------------------------------
Note (1): J095819.36+013530.52 is a narrow-line quasar
Note (2): logL1350 for J095848.37+013818.12 and J220522.42+0.21149.32 were
measured from broad-band photometry.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-May-2026