J/MNRAS/504/2767 A Chandra survey of z ≥ 4.5 quasars (Li+, 2021)
A Chandra survey of z ≥ 4.5 quasars.
Li J.-T., Wang F., Yang J., Bregman J.N., Fan X., Zhang Y.
<Mon. Not. R. Astron. Soc., 504, 2767-2782 (2021)>
=2021MNRAS.504.2767L 2021MNRAS.504.2767L (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources ; Accretion ; Active gal. nuclei ; Black holes ;
QSOs ; Redshifts ; Photometry ; Radio sources ; Infrared sources ;
Optical
Keywords: catalogues; quasars: general - distance scale - early Universe -
X-rays: galaxies
Abstract:
X-ray observations provide a unique probe of the accretion disc corona
of supermassive black holes (SMBHs). In this paper, we present a
uniform Chandra X-ray data analysis of a sample of 152 z ≥ 4.5
quasars. We firmly detect 46 quasars of this sample in 0.5-2 keV above
3σ and calculate the upper limits of the X-ray flux of the
remaining. We also estimate the power-law photon index of the X-ray
spectrum of 31 quasars. 24 of our sample quasars are detected in the
FIRST or NVSS radio surveys; all of them are radio-loud. We
statistically compare the X-ray properties of our z ≥ 4.5 quasars
to other X-ray samples of active galactic nuclei (AGNs) at different
redshifts. The relation between the rest-frame X-ray luminosity and
other quasar parameters, such as the bolometric luminosity, UV
luminosity, or SMBH mass, shows large scatters. These large scatters
can be attributed to the narrow luminosity range at the highest
redshift, the large measurement error based on relatively poor X-ray
data, and the inclusion of radio-loud quasars in the sample. The
LX-LUV relationship is significantly sublinear. We do not find a
significant redshift evolution of the LX-LUV relation, expressed
either in the slope of this relation, or the departure of individual
AGNs from the best-fitting αOX-LUV relation
(ΔαOX). The median value of the X-ray photon index is
Γ ~= 1.79, which does not show redshift evolution from z =
0 to z ∼ 7. The X-ray and UV properties of the most distant
quasars could potentially be used as a standard candle to constrain
cosmological models. The large scatter of our sample on the Hubble
diagram highlights the importance of future large unbiased deep X-ray
and radio surveys in using quasars in cosmological studies.
Description:
Due to the modern X-ray telescopes such as the Chandra and
XMM-Newton, deep X-ray surveys of AGNs over a large redshift range,
especially at the highest redshifts, become possible over the past two
decades.
The quasars studied in this paper are based on the collection of known
z => 4.5 , z ∼ 5-6 , and z > 6 quasars (see section 2.1 sample
selection for more details). The original sample includes 1133
z => 4.5 quasars with spectroscopic redshift and the rest-frame UV
magnitude. We select all the quasars covered by at least one archival
Chandra/ACIS observation, and obtain 153 quasars. We further remove
the quasar J120312-001118.
The final sample studied in this paper includes 152 quasars, basic
parameters of the sample are summarized in tablea1.dat. The X-ray
luminosity of high-z quasars are often computed in different ways in
different literatures, which could cause significant systematic
biases. Therefore, we reanalyse all the Chandra observations of our
sample quasars, in order to ensure that their X-ray properties are
derived in a uniform way. We develop a uniform Chandra data reduction
procedure for high-z quasars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 1077 152 Observational and physical properties
of the 152 QSos final sample
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See also:
J/ApJ/819/24 : z>4.5 QSOs with SDSS and WISE. I. Opt. spectra (Wang+, 2016)
IX/59 : XMM-Newton Serendipitous Source Catalogue 4XMM-DR9 (Webb+, 2020)
J/ApJ/829/33 : Luminous of high-z QSOs with SDSS and WISE. II (Yang+, 2016)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- QSO Name of the QSO in the format of
Jhhmmss ddmmss (QSO) (1)
17- 40 A24 --- Name Other name of the QSO (OTHERNAMES)
42- 43 I2 h RAh Right ascension (J2000) (QSORAh)
45- 46 I2 min RAm Right ascension (J2000) (QSORAm)
48- 55 F8.5 s RAs Right ascension (J2000) (QSORAs)
57 A1 --- DE- Sign of declination (J2000)
58- 59 I2 deg DEd Declination (J2000) (QSODEd)
61- 62 I2 arcmin DEm Declination (J2000) (QSODEarcmin)
64- 72 F9.6 arcsec DEs Declination (J2000) (QSODEarcsec)
74- 83 F10.6 deg RAdeg Right ascension in degrees (J2000)
(RAdeg)
85- 94 F10.6 deg DEdeg Declination in decimal degrees (J2000)
(DECdeg)
96-132 A37 --- Ref Reference discovering the QSO
(DISCOVERY)
134-140 F7.5 --- zQSO Best Redshift of the QSO (REDSHIFT)
142-149 F8.6 --- e_zQSO ? Error of the redshift (REDSHIFT_ERR)
151-157 A7 --- zMETHOD Method used to measure the redshift
(REDSHIFT_METHOD) (2)
159-195 A37 --- r_zQSO Reference of the adopted redshift
data (REDSHIFT_REF)
197-206 F10.6 mag 1450Mag Absolute magnitude at 1450 angstrom
(M1450)
208-215 F8.6 10-28mW/m2/Hz F2500 Rest frame monochromatic flux at 2500
angstrom (F2500)
217-224 F8.6 10+25W/Hz L2500 Rest frame monochromatic luminosity at
2502 angstrom (LNUR2500)
226-236 F11.6 ct NCtSoft Background subtracted net counts
number in 0.5-2 keV (NETCTSSOFT)
238-247 F10.6 ct NCtHard Background subtracted net counts
number in 2-7 keV (NETCTSHARD)
249-259 F11.6 ct NCtFull Background subtracted net counts
number in 0.5-7 keV (NETCTSFULL)
261-269 F9.6 ct s_NCtSoft 1 sigma background rms in 0.5-2 keV
(SIGMASOFT)
271-279 F9.6 ct s_NCtHard 1 sigma background rms in 2-7 keV
(SIGMAHARD)
281-289 F9.6 ct s_NCtFull 1 sigma background rms in 0.5-7 keV
(SIGMAFULL)
291-299 F9.6 --- S/NSoft Signal-to-noise ratio of the QSO
in 0.5-2 keV (QSOSNRSOFT)
301-309 F9.6 --- S/NHard Signal-to-noise ratio of the QSO
in 2-7 keV (QSOSNRHARD)
311-319 F9.6 --- S/NFull Signal-to-noise ratio of the QSO
in 0.5-7 keV (QSOSNRFULL)
321-331 F11.6 10+37W LX Observational frame 0.5-2 keV
luminosity (LX)
333-341 F9.6 10+37W e_LX Lower error 1 sigma of LX (ELXL)
343-351 F9.6 10+37W E_LX Upper error 1 sigma of LX (ELXH)
353-363 F11.6 10-33mW/m2/Hz F2kev Rest frame monochromatic flux
at 2 keV (F2KEV)
365-374 F10.6 10-33mW/m2/Hz e_F2kev Lower error 1 sigma of F2kev (EF2KEVL)
376-384 F9.6 10-33mW/m2/Hz E_F2kev Upper error 1 sigma of F2kev (EF2KEVH)
386-394 F9.6 10-14mW/m2 FX Observational frame 0.5-2 keV flux
(FX)
396-403 F8.6 10-14mW/m2 e_FX Lower error 1 sigma of FX (EFXL)
405-412 F8.6 10-14mW/m2 E_FX Upper error 1 sigma of FX (EFXH)
414-424 F11.6 10+37W LXRest Rest frame 2-10 keV luminosity
(LXREST)
426-434 F9.6 10+37W e_LXRest Lower error 1 sigma of LXRest
(ELXRESTL)
436-444 F9.6 10+37W E_LXRest Upper error 1 sigma of LXRest
(ELXRESTH)
446-454 F9.6 10-14mW/m2 FXRest Rest frame 2-10 keV flux (FXREST)
456-463 F8.6 10-14mW/m2 e_FXRest Lower error 1 sigma of FXRest
(EFXRESTL)
465-472 F8.6 10-14mW/m2 E_FXRest Upper error 1 sigma of FXRest
(EFXRESTH)
474-482 F9.6 --- Gamma Photon index Gamma of the power-law
spectral fit in X-ray band
(PHOINDEX) (3)
484-491 F8.6 --- e_Gamma Lower error 1 sigma of Gamma
(EPHOINDEXL)
493-500 F8.6 --- E_Gamma Upper error 1 sigma of Gamma
(EPHOINDEXH)
502-510 F9.6 --- alphaOX Optical-to-X-ray spectral slope
(ALPHAOX)
512-520 F9.6 --- e_alphaOX Lower error 1 sigma of alphaOX
(EALPHAOXL)
522-529 F8.6 --- E_alphaOX Upper error 1 sigma of alphaOX
(EALPHAOXH)
531-625 A95 --- ObsIDCha List of Chandra observation ID used
in this work (OBSIDCHANDRA)
627-637 F11.6 ks TexpCha Total effective Chandra exposure
time (TEXPCHANDRA)
639-840 A202 --- XMMdata List of XMM-Newton observations
covering this QSO (XMMDATA)
842-874 A33 --- XMMObj Object name of the XMM-Newton
observations covering this QSO
(XMMOBJ)
876-953 A78 --- NIRref References of the near-IR spectra
(NIRREF)
955-962 F8.6 10+10Msun MSMBH Supermassive black hole mass
(MSMBH) (4)
964-971 F8.6 10+10Msun e_MSMBH Lower error 1 sigma of MSMBH
(EMSMBHL)
973-980 F8.6 10+10Msun E_MSMBH Upper error 1 sigma of MSMBH
(EMSMBHH)
982-989 F8.6 --- lambdaEd Eddington ratio of the SMBH
(LAMBDAEDD) (4)
991-998 F8.6 --- e_lambdaEd Lower error 1 sigma of lambdaEdd
(ELAMBDAEDDL)
1000-1007 F8.6 --- E_lambdaEd Upper error 1 sigma of lambdaEdd
(ELAMBDAEDDH)
1009-1057 A49 --- Note Additional special notes on
individual QSOs (NOTE)
1059-1068 F10.6 mJy FRadio Integrated 20 cm radio flux
(RADIOFLUX)
1070-1077 F8.6 arcsec DRadio Separation of the radio position
from the optical position (RADIODIST)
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Note (1): We add a label 'c' in front of the QSO J name if the background
counts number is inferior or equal to 10.
Note (2): The method used in measuring the redshift can be
'C II' (using the C II at 158 um line in radio band),
'Mg II' (using the Mg II at 2787 Angstroem line in near-IR band),
'Ly-aplha' (using the Ly alpha at 1216 angstrom in optical band).
Note (3): Set to 2.0 with error equals 0.0 if no reliable estimate on gamma.
Note (4): MSMBH and lambdaEd of different QSOs are collected from different
references, so the confidence range of the error is random, and
not necessarily 1 sigma.
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 30-Apr-2024