J/ApJ/923/262 NIR spectroscopic obs. of z>6.5 quasars (Yang+, 2021)
Probing early supermassive black hole growth and quasar evolution with near-
infrared spectroscopy of 37 reionization-era quasars at 6.3<z≤7.64.
Yang J., Wang F., Fan X., Barth A.J., Hennawi J.F., Nanni R., Bian F.,
Davies F.B., Farina E.P., Schindler J.-T., Banados E., Decarli R.,
Eilers A.-C., Green R., Guo H., Jiang L., Li J.-T., Venemans B.,
Walter F., Wu X.-B., Yue M.
<Astrophys. J., 923, 262 (2021)>
=2021ApJ...923..262Y 2021ApJ...923..262Y
ADC_Keywords: QSOs; Ultraviolet; Spectra, infrared; Redshifts;
Equivalent widths; Black holes
Keywords: Quasars ; Supermassive black holes ; Reionization
Abstract:
We report the results of near-infrared spectroscopic observations of
37 quasars in the redshift range 6.3<z≤7.64, including 32 quasars at
z>6.5, forming the largest quasar near-infrared spectral sample at
this redshift. The spectra, taken with Keck, Gemini, VLT, and
Magellan, allow investigations of central black hole mass and quasar
rest-frame ultraviolet spectral properties. The black hole masses
derived from the MgII emission lines are in the range
(0.3-3.6)x109M☉, which requires massive seed black holes with
masses ≥103-104M☉, assuming Eddington accretion since z=30.
The Eddington ratio distribution peaks at λEdd∼0.8 and has a
mean of 1.08, suggesting high accretion rates for these quasars. The
CIV-MgII emission-line velocity differences in our sample show an
increase of CIV blueshift toward higher redshift, but the evolutionary
trend observed from this sample is weaker than the previous results
from smaller samples at similar redshift. The FeII/MgII flux ratios
derived for these quasars up to z=7.6, compared with previous
measurements at different redshifts, do not show any evidence of
strong redshift evolution, suggesting metal-enriched environments in
these quasars. Using this quasar sample, we create a quasar composite
spectrum for z>6.5 quasars and find no significant redshift evolution
of quasar broad emission lines and continuum slope, except for a
blueshift of the CIV line. Our sample yields a strong broad absorption
line quasar fraction of ∼24%, higher than the fractions in
lower-redshift quasar samples, although this could be affected by
small sample statistics and selection effects.
Description:
The NIR spectral sample presented in this paper is constructed based
on
(1) quasars from the survey described in W19 (Wang+ 2019ApJ...884...30W 2019ApJ...884...30W)
and Y19 (Yang+ 2019AJ....157..236Y 2019AJ....157..236Y),
(2) other known z>7 quasars (i.e., J1120+0641 and J1342+0928),
(3) quasars observed in our Keck/NIRES NIR spectroscopic programs, and
(4) other z>6.5 quasars (i.e., J0024+3913 and J2232+2930) that are not
in the first three categories but have Gemini/GNIRS data in the
archive.
We obtained NIR spectroscopy of our quasar sample using the following
facilities: Keck/NIRES (Near-Infrared Echellette Spectrometer),
Gemini/GNIRS (Gemini Near-Infrared Spectrograph), VLT/X-Shooter,
Gemini/F2 (FLAMINGOS-2 near-infrared imaging spectrograph), and
Magellan/FIRE.
We observed 18 quasars with Keck/NIRES from 2018 to 2020 (0.94-2.45um,
R∼2700). Spectra of 22 quasars were taken with Gemini North/GNIRS,
including 18 quasars observed in our programs from 2018 to 2020 and
four from Gemini archival data (0.85-2.5um, R∼500-700). In addition,
we observed three quasars with VLT/X-Shooter (ID: 0103.A-0423(A)) in
2019. X-Shooter covers the wavelength range from 3000 to 24800Å
(R∼8900 and ∼8100). Quasars J0313-1806 and J0525-2406 were observed
with Gemini South F2 in 2019 (1.45-2.5um, R∼400). In addition to the
NIRES, GNIRS, and F2 observations, quasar J0313-1806 was also observed
with Magellan/FIRE (0.8-2.5um) in echelle mode in 2019 November and
December (R∼4800 and ∼3600).
All results refer to a ΛCDM cosmology with parameters
ΩΛ=0.7, Ωm=0.3, and h=0.7.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 150 38 Quasar and observation information of the
37 quasars in the sample
table2.dat 161 37 Spectral fitting and quasar properties
table3.dat 32 1849 z>6.5 quasar composite spectrum
table4.dat 69 37 Quasar BH masses derived from the spectral fitting
based on the
Vestergaard & Wilkes (2001ApJS..134....1V 2001ApJS..134....1V ; VW01)
iron template
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See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/359 : The VISTA Hemisphere Survey (VHS) cat. DR4.1 (McMahon+, 2013)
II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)
II/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)
J/ApJ/613/682 : AGN masses & broad-line region sizes (Peterson+, 2004)
J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)
J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)
J/ApJ/699/800 : Mass functions of active black holes (Vestergaard+, 2009)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/AJ/148/13 : Redshifts of 65 CANDELS supernovae (Rodney+, 2014)
J/ApJS/227/11 : PS1 z>5.6 quasars follow-up (Banados+, 2016)
J/ApJ/825/126 : SEAMBHs. V. The third year (Du+, 2016)
J/A+A/585/A87 : Quasar composite made from bright QSOs (Selsing+, 2016)
J/MNRAS/465/2120 : Correcting CIV-based virial BH masses (Coatman+, 2017)
J/ApJ/856/6 : SEAMBHs IX. 10 new Hβ light curves (Du+, 2018)
J/MNRAS/487/3305 : Broad-line velocity shifts in 1.5<z<7.5 QSOs (Meyer+, 2019)
J/ApJ/873/35 : Gemini GNIRS NIR sp. of 50 QSOs at z≳5.7 (Shen+, 2019)
J/ApJ/901/55 : SDSS-RM project: MgII lags from 4yrs (Homayouni+, 2020)
J/ApJ/905/51 : X-SHOOTER/ALMA QSOs at 5.78<z<7.54. I. (Schindler+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Position based identifier (JHHMMSS.ss+DDMMSS.s)
21- 21 A1 --- f_Name Flag on Name (1)
23- 32 A10 --- SName Short Name used in text
34- 48 A15 --- Inst Instrument used
50- 61 A12 s ExpTime Exposure time(s)
63- 68 F6.4 --- zsp [6.35/7.65]? Spectroscopic redshift
70- 75 F6.4 --- e_zsp [0.0001/0.05]? Uncertainty in zsp
77-115 A39 --- Disc Discovery, ADS bibcode(s)
117-117 A1 --- [CII] [YN] Detection of [CII]
119-137 A19 --- r_zsp Reference for zsp, ADS bibcode (2)
139-139 A1 --- NIR [YN] Previously published BH mass measurements
141-145 F5.2 mag Jmag [17.46/21.3]? J-band (AB system) photometric
data used to scale the NIR spectra (3)
147-150 F4.2 mag e_Jmag [0.02/0.3]? Uncertainty in Jmag
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Note (1): Notes on object names. Code as follows:
d = These quasars are also named as PSO J006.1240+39.2219, PSO
J011.3898+09.0324, PSO J172.3556+18.7734, PSO J261.0364+19.0286, and
PSO J338.2298+29.5089, respectively;
e = These quasars are previously unpublished. Details of their selection
and identification will be reported separately (J. Yang et al. in
prep).
Note (2): The reference for the redshifts used in the spectral analysis. If
the quasar has a [CII] detection (column [CII] = Y), the reference is
for the [CII]-based redshift, and the redshift listed in column z is
the [CII]-based redshift. Most of the [CII] detections are from a
series of ALMA/NOEMA programs that will be reported in detail in F. Wang
et al. (in prep).
Note (3): The J-band photometric data used to scale the NIR spectra. For
the quasars J0525-2406, J0923+0753, and J1058+2930 without J data, we
used Y or K-band photometry, as described in Section 2.3.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Position based identifier
(JHHMMSS.ss+DDMMSS.s)
21- 30 A10 --- SName Short Name used in text
32- 34 A3 --- f_Name Flag(s) on Name (1)
36- 41 F6.4 --- z[CII] [6.46/7.65]? Redshift based on [CII]
43- 48 F6.4 --- e_z[CII] [0.0001/0.004]? Uncertainty in z[CII]
50- 54 F5.3 --- zCIV [6.33/7.53]? Redshift based on CIV
56- 60 F5.3 --- e_zCIV [0.001/0.04]? Uncertainty in zCIV
62- 67 F6.4 --- zMgII [6.3/7.62] Redshift based on MgII
69- 74 F6.4 --- e_zMgII [0.0002/0.02] Uncertainty in zMgII
76- 81 F6.2 mag M1450 [-27.5/-25] Absolute rest-frame 1450Å
magnitude
83- 87 I5 km/s FWHM-CIV [1908/11989]? Full width at half maximum,
CIV line
89- 92 I4 km/s e_FWHM-CIV [26/3206]? Uncertainty in FWHM-CIV
94- 97 I4 km/s FWHM-MgII [1741/5504] Full width at half maximum,
MgII line
99-101 I3 km/s e_FWHM-MgII [14/763] Uncertainty in FWHM-MgII
103-106 F4.1 0.1nm EW-CIV [5.9/70.1]? Equivalent width, CIV,
in Angstroms
108-111 F4.1 0.1nm e_EW-CIV [0.9/26.2]? Uncertainty in EW-CIV
113-116 F4.1 0.1nm EW-MgII [7.9/34.7] Equivalent width, MgII,
in Angstroms
118-121 F4.1 0.1nm e_EW-MgII [0.6/18.2] Uncertainty in EW-MgII
123-126 F4.1 10+39W LBol [4.6/34] Bolometric luminosity,
10+46erg/s
128-130 F3.1 10+39W e_LBol [0.1/3.5] Uncertainty in LBol
132-136 F5.3 10+9Msun MBH [0.26/3.6] Black hole mass
138-142 F5.3 10+9Msun e_MBH [0.003/0.7] Uncertainty in MBH
144-148 F5.2 --- alpha [-1.74/-0.24] Power-law continuum slope
150-153 F4.2 --- e_alpha [0.01/1] Uncertainty in alpha
155-157 F3.1 --- REdd [0.3/2.3] Eddington Ratio, Lbol/LEdd
159-161 F3.1 --- e_REdd [0.1/1] Uncertainty in REdd
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Note (1): Flags on Name. Code as follows:
b = The measurements of the quasar J0439+1634 have been corrected for
gravitational lensing using a magnification of 51.3,
Fan et al. (2019ApJ...870L..11F 2019ApJ...870L..11F);
c = BAL quasars. See details in Section 6.2.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.1 0.1nm lambda [1150.5/2998.5] Wavelength, rest frame, Angstroms
8- 29 F22.19 --- Flam [-0.04/3.14] Flux density, arbitrary units
31- 32 I2 --- Nqso [4/38] Number of QSOs contributing to data point
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Position based identifier
(JHHMMSS.ss+DDMMSS.s)
21- 30 A10 --- SName Short Name used in text
32- 35 F4.1 10+39W LBol [5/37] Bolometric luminosity, 10+46erg/s
37- 39 F3.1 10+39W e_LBol [0.1/4] Uncertainty in LBol
41- 44 I4 km/s FWHM-MgII [1729/7825] Full width at half maximum,
MgII line
46- 49 I4 km/s e_FWHM-MgII [8/1314] Uncertainty in FWHM-MgII
51- 55 F5.3 10+9Msun MBH [0.24/8.4] Black hole mass
57- 61 F5.3 10+9Msun e_MBH [0.001/1.5] Uncertainty in MBH
63- 65 F3.1 --- REdd [0.2/2.3] Eddington Ratio, Lbol/LEdd
67- 69 F3.1 --- e_REdd [0.1/1] Uncertainty in REdd
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 05-Jun-2023