J/ApJ/796/140 Circumgalactic medium surrounding z∼2 quasars (Prochaska+, 2014)
Quasars probing quasars.
VII. The pinnacle of the cool circumgalactic medium surrounds massive
z∼2 galaxies.
Prochaska J.X., Lau M.W., Hennawi J.F.
<Astrophys. J., 796, 140 (2014)>
=2014ApJ...796..140P 2014ApJ...796..140P (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Clusters, galaxy ; Redshifts ; Equivalent widths
Keywords: galaxies: clusters: intracluster medium; intergalactic medium
quasars: absorption lines
Abstract:
We survey the incidence and absorption strength of the metal-line
transitions C II 1334 and C IV 1548 from the circumgalactic medium
(CGM) surrounding z∼2 quasars, which act as signposts for massive dark
matter halos Mhalo∼1012.5 M☉. On scales of the virial radius
(rvir∼160 kpc), we measure a high covering fraction fC=0.73±0.10 to
strong C II 1334 absorption (rest equivalent width W1334≥0.2 Å),
implying a massive reservoir of cool (T∼104 K) metal enriched gas.
We conservatively estimate a metal mass exceeding 108 M☉. We
propose that these metals trace enrichment of the incipient
intragroup/intracluster medium that these halos eventually inhabit.
This cool CGM around quasars is the pinnacle among galaxies observed
at all epochs, as regards covering the fraction and average equivalent
width of H I Lyα and low-ion metal absorption. We argue that the
properties of this cool CGM primarily reflect the halo mass, and that
other factors such as feedback, star-formation rate, and accretion
from the intergalactic medium are secondary. We further estimate that
the CGM of massive, z∼2 galaxies accounts for the majority of strong
Mg II absorption along random quasar sightlines. Last, we detect an
excess of strong C IV 1548 absorption (W1548≥0.3 Å) over random
incidence to the 1 Mpc physical impact parameter and measure the
quasar-C IV cross-correlation function: ζCIV-Q(r)=(r/r0)-γ
with r0=7.5-1.4+2.8 h-1 Mpc and γ=1.7-0.2+0.1.
Consistent with previous work on larger scales, we infer that this
highly ionized C IV gas traces massive (1012 M☉) halos.
Description:
The sample of quasar pairs analyzed here is a subset of the sample
studied in QPQ6 (Cantalupo et al. 2014Natur.506...63C 2014Natur.506...63C) for H I Lyα
absorption. Specifically, we have restricted the current study to
those pairs where the signal-to-noise ratio (S/N) at H I Lyα
exceeds 9.5 per rest-frame Å. This facilitates a more precise
evaluation of H I Lyα and generally insures sufficient S/N redward
of Lyα for the metal-line analysis. Quasar emission redshifts are
taken directly from QPQ6 (Cantalupo et al. 2014Natur.506...63C 2014Natur.506...63C),
following the methodology described in that manuscript. Briefly, we
adopt a custom line-centering algorithm to centroid one or more far-UV
emission lines and adopt the analysis of Shen et al. (2007, J/AJ/133/2222)
to combine these measurements and assess systematic uncertainty in the
final value. The median emission redshift of the 427 pairs is
zemmedian=2.35 and the median uncertainty in the redshift measurements
is ∼520 km/s. The impact parameters range from R⊥=39 kpc to 1 Mpc,
with 52 pairs having R⊥<200 kpc.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 524 QPQ7 Spectra
table2.dat 81 427 QPQ7 EW Measurements
table5.dat 53 223 SDSS C IV Survey
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See also:
VII/69 : Asiago Catalogue of QSOs (Barbieri+ 1983)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)
J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)
J/MNRAS/401/2715 : CIV column densities in z<2.5 QSOs (D'odorico+, 2010)
J/ApJ/762/L19 : Quasar pairs spectroscopy (Prochaska+, 2013)
J/ApJ/776/136 : QPQ VI. HI absorption of z∼2 quasars (Prochaska+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- b/gQ Background quasar identifier (JHHMMSS.ss+DDMMSS.s)
21- 39 A19 --- f/gQ Foreground quasar identifier (JHHMMSS.ss+DDMMSS.s)
41- 46 F6.4 --- zfg Foreground quasar redshift
48- 50 I3 kpc Rphys Impact parameter
52- 71 A20 --- Instr Instrument used in the observation
73- 81 A9 0.1nm Wave Wavelength coverage of Instr in Angstroms (1)
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Note (1): Rest-frame wavelengths at the f/g quasar redshift where the spectra
of the b/g quasar exceeds S/N>5 per pixel.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- f/gQ Foreground quasar identifier (JHHMMSS.ss+DDMMSS.s)
21- 39 A19 --- b/gQ Background quasar identifier (JHHMMSS.ss+DDMMSS.s)
41- 43 I3 kpc Rphys Impact parameter
45- 49 F5.3 --- zfg Foreground quasar redshift
51- 55 I5 km/s delv Velocity offset (1)
57- 62 F6.3 0.1nm W1334 ? Equivalent width of C II 1334Å line (G1)
64- 68 F5.3 0.1nm e_W1334 ? Uncertainty in W1334 (G1)
70- 75 F6.3 0.1nm W1548 ? Equivalent width of C IV 1548Å line (G1)
77- 81 F5.3 0.1nm e_W1548 ? Uncertainty in W1548 (G1)
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Note (1): From zLyα to zfg. Note that absorption lines were assessed
only for data with S/NLyα>9.5.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Quasar Quasar identifier (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.3 --- zq Quasar emission redshift
27- 31 F5.3 --- zstart Starting redshift (1)
33- 37 F5.3 --- zend Ending redshift (2)
39- 43 F5.3 --- zCIV ? C IV 1548 line redshift
45- 48 F4.2 0.1nm WCIV ? Equivalent width of C IV 1548Å line (G1)
50- 53 F4.2 0.1nm e_WCIV ? Uncertainty in WCIV
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Note (1): For the C IV search. Defined as (1+zq)*1238.8/1548.195-1.
Note (2): For the C IV search. Defined as 4000 km/s blueward of the quasar
redshift.
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Global notes:
Note (G1): In units of Angstroms.
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History:
From electronic version of the journal
References:
Ho et al. Paper I 2017ApJ...835..267H 2017ApJ...835..267H
Hennawi et Prochaska Paper II 2007ApJ...655..735H 2007ApJ...655..735H
Prochaska et Hennawi Paper III 2009ApJ...690.1558P 2009ApJ...690.1558P
Hennawi et Prochaska Paper IV 2013ApJ...766...58H 2013ApJ...766...58H
Prochaska et al. Paper V 2013ApJ...762L..19P 2013ApJ...762L..19P, Cat. J/ApJ/762/L19
Prochaska et al. Paper VI 2013ApJ...776..136P 2013ApJ...776..136P, Cat. J/ApJ/776/136
Lau et al. Paper VIII 2016ApJS..226...25L 2016ApJS..226...25L
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 11-Aug-2017