J/ApJ/884/151 Lyman cont. luminosity of SDSS quasar pairs at z∼3 (Jalan+, 2019)
Probing the environment of high-z quasars using the proximity effect in
projected quasar pairs.
Jalan P., Chand H., Srianand R.
<Astrophys. J., 884, 151 (2019)>
=2019ApJ...884..151J 2019ApJ...884..151J
ADC_Keywords: QSOs; Redshifts; Photometry, SDSS; Spectra, optical
Keywords: Quasars ; Lyman alpha forest
Abstract:
We have used spectra of 181 projected quasar pairs at separations
≤1.5' from the Sloan Digital Sky Survey Data Release 12 in the
redshift range of 2.5-3.5 to probe the proximity regions of the
foreground quasars. We study the proximity effect both in the
longitudinal and in the transverse directions, by carrying out a
comparison of the Lyα absorption lines originating from the
vicinity of quasars to those originating from the general
intergalactic medium at the same redshift. We found an enhancement in
the transmitted flux within 4Mpc to the quasar in the longitudinal
direction. However, the trend is found to be reversed in the
transverse direction. In the longitudinal direction, we derived an
excess overdensity profile showing an excess up to r≤5Mpc after
correcting for the quasar's ionization, taking into account the effect
of low spectral resolution. This excess overdensity profile matches
with the average overdensity profile in the transverse direction
without applying any correction for the effect of the quasar's
ionization. Among various possible interpretations, we found that the
anisotropic obscuration of the quasar's ionization seems to be the
most probable explanation. This is also supported by the fact that all
of our foreground quasars happen to be type 1 AGNs. Finally, we
constrain the average quasar's illumination along the transverse
direction as compared to that along the longitudinal direction to be
≤27% (3σ confidence level).
Description:
We have used the SDSS DR12 quasar spectroscopic database compiled by
Paris+ (2017, VII/279).
This contains a total of 297301 spectroscopically confirmed quasars
having spectra covering the observed wavelength range of 3650-10400Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 157 181 Basic properties of our sample of 181 quasar pairs
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See also:
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/A+A/376/28 : Inversion of the HE 1122-1648 UVES spectrum (Rollinde+ 2001)
J/MNRAS/335/555 : Lyman-alpha forest of 5 QSOs (Kim+, 2002)
J/ApJ/651/61 : Opt. thick absorbers near luminous QSOs (Hennawi+, 2006)
J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)
J/MNRAS/391/1457 : Lymanα forest in QSO pairs (Kirkman+, 2008)
J/A+A/505/1087 : DLAs in SDSS-DR7 (Noterdaeme+, 2009)
J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)
J/A+A/547/L1 : SDSS-III DR9 DLA catalogue (Noterdaeme+, 2012)
J/MNRAS/435/3306 : Candidate type II QSOs in SDSS III (Alexandroff+, 2013)
J/ApJ/776/136 : QPQ VI. HI absorption of z∼2 quasars (Prochaska+, 2013)
J/ApJ/796/140 : Circumgal. medium surrounding z∼2 QSOs (Prochaska+, 2014)
J/ApJ/831/7 : SDSS-RM project: peak velocities of QSOs (Shen+, 2016)
J/MNRAS/468/77 : Sample of confirmed quasar pairs (Eftekharzadeh+, 2017)
J/ApJ/847/81 : HeII photoionization rates of quasars (Schmidt+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/181] Running sequential number
9- 28 A20 --- Name-bg Name of background quasars
(JHHMMSS.ss+DDMMSS.ss)
34- 41 F8.6 --- z-bg [2.7/3.711] Redshift of background quasar
47- 54 F8.6 --- e_z-bg [0.004/0.006] Error in redshift of
background quasar
60- 65 F6.3 [10-7W/Hz] L-bg [29/31.2] Log, luminosity at 912Å of
the background quasar, erg/s/Hz
71- 76 F6.3 --- rmag-bg [18.3/22.5] r-band magnitude of the
background quasar
82- 101 A20 --- Name-fg Name of foreground quasars
(JHHMMSS.ss+DDMMSS.ss)
107- 114 F8.6 --- z-fg [2.56/3.46] Redshift of foreground quasar
120- 127 F8.6 --- e_z-fg [0.003/0.006] Error in redshift of
foreground quasar
133- 138 F6.3 [10-7W/Hz] L-fg [28.8/31.11] Log, luminosity at 912Å of
the foreground quasar, erg/s/Hz
144- 149 F6.3 --- rmag-fg [18.4/22] r-band magnitude of the
foreground quasar
155- 157 I3 kpc R-perp [26/731] Perpendicular distance between
pairs sightline at z-fg
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Mar-2021