J/ApJ/904/44 Evolution of CIV absorbers. I. Absorber properties (Hasan+, 2020)
Evolution of CIV absorbers.
I. The cosmic incidence.
Hasan F., Churchill C.W., Stemock B., Mathes N.L., Nielsen N.M.,
Finlator K., Doughty C., Croom M., Kacprzak G.G., Murphy M.T.
<Astrophys. J., 904, 44 (2020)>
=2020ApJ...904...44H 2020ApJ...904...44H
ADC_Keywords: QSOs; Spectra, optical; Spectra, ultraviolet; Spectra, infrared;
Redshifts
Keywords: Quasar absorption line spectroscopy ; Circumgalactic medium ;
Intergalactic medium ; Galaxy evolution ; High resolution
spectroscopy
Abstract:
We present a large high-resolution study of the distribution and
evolution of CIV absorbers, including the weakest population with
equivalent widths Wr<0.3Å . By searching 369 high-resolution,
high signal-to-noise ratio spectra of quasars at 1.1≤zem≤5.3 from
Keck/HIRES and VLT/UVES, we find 1268 CIV absorbers with
Wr≳0.05Å (our ∼50% completeness limit) at redshifts
1.0≤z≤4.75. A Schechter function describes the observed equivalent
width distribution with a transition from power-law to exponential
decline at Wr≳0.5Å . The power-law slope α rises by ∼7%,
and the transition equivalent width W* falls by ∼20% from =1.7 to
3.6. We find that the comoving redshift path density, dN/dX, of
Wr≥0.05Å absorbers rises by ∼1.8 times from z∼4.0 to 1.3, while
the Wr≥0.6Å dN/dX rises by a factor of ∼8.5. We quantify the
observed evolution by a model in which dN/dX decreases linearly with
increasing redshift. The model suggests that populations with larger
Wr thresholds evolve faster with redshift and appear later in the
universe. The cosmological Technicolor Dawn simulations at z=3-5
overproduce the observed abundance of absorbers with Wr≤0.3Å
while yielding better agreement at higher Wr. Our empirical linear
model successfully describes CIV evolution in the simulations and
the observed evolution of Wr≥0.6Å CIV for the past ∼12Gyr.
Combining our measurements with the literature gives us a picture of
CIV absorbing structures becoming more numerous and/or larger in
physical size over the last ∼13Gyr of cosmic time (z∼6-0).
Description:
We have analyzed 369 high-resolution, high signal-to-noise ratio (S/N)
quasar spectra obtained with the High Resolution Echelle Spectrometer
(HIRES) spectrograph and the Ultraviolet and Visual Echelle
Spectrograph (UVES) spectrograph from the Keck and Very Large
Telescope (VLT) observatories, respectively. The wavelength coverage
of the spectra spans approximately 3000-10000Å, though there is
variable coverage in this range from spectrum to spectrum. (R=36000).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 369 List of QSO spectra
table2.dat 67 1268 Data of CIV absorber properties
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See also:
J/A+A/283/759 : CIV QSO absorption systems (Petitjean+ 1994)
J/ApJ/596/768 : Optical depths in 19 QSOs (Schaye+, 2003)
J/A+A/473/791 : CIV absorption in DLAs and sub-DLAs systems (Fox+, 2007)
J/ApJ/679/194 : Low-z intergalactic medium. III. (Danforth+, 2008)
J/ApJ/690/20 : Models of the AGN and black hole populations (Shankar+, 2009)
J/ApJ/708/868 : CIV candidates (Cooksey+, 2010)
J/MNRAS/401/2715 : CIV column densities in z<2.5 QSOs (D'odorico+, 2010)
J/MNRAS/422/3370 : Spatial variation in fine-structure constant (King+, 2012)
J/ApJ/761/112 : High-redshift MgII absorption QSOs with FIRE (Matejek+, 2012)
J/ApJ/755/89 : Metallicities of damped Lyα systems (Rafelski+, 2012)
J/ApJ/763/37 : Metals in SDSS QSOs.I. 1.5<z<4.5 CIV absorbers (Cooksey+, 2013)
J/MNRAS/435/1198 : z∼6 QSOs CIV doublet absorption systems (D'Odorico+, 2013)
J/ApJ/776/114 : MAGIICAT. I. MgII Absorber-Galaxy Catalog (Nielsen+, 2013)
J/MNRAS/445/2061 : Absorption multiphase circumgalactic medium (Liang+, 2014)
J/ApJ/815/91 : z<0.16 CIV absorbers from HST/COS QSO spectra (Burchett+, 2015)
J/ApJS/221/32 : Narrow MgII absorption lines from SDSS-DR9Q (Chen+, 2015)
J/AJ/150/111 : KODIAQ DR1 (O'Meara+, 2015)
J/ApJ/833/283 : HI-selected Lyman limit systems metallicities (Lehner+, 2016)
J/A+A/611/A76 : DLAS dust-corrected metallicity (De Cia+, 2018)
J/ApJ/883/163 : OI abs. search in Keck & VLT spectra 199 QSOs (Becker+, 2019)
J/MNRAS/488/1035 : AGN UV luminosity function (Kulkarni+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- QSO Quasar name in J2000 format (1)
18- 22 F5.3 --- z [1.16/5.3] Quasar emission redshift
26- 35 A10 --- Inst Quasar spectrum observation facility
38- 42 I5 0.1nm wmin [2636/7648] Minimum wavelength CIV search space (2)
45- 49 I5 0.1nm wmax [3302/9578] Maximum wavelength CIV search space (3)
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Note (1): QSO name taken from Veron-Cetty & Veron, 2001, VII/224.
Note (2): Blueward limit of the portion of the spectrum that is searched for
CIV absorbers, defined by Lya 1215 emission of the quasar
Note (3): Redward limit of the portion of the spectrum that is searched for
CIV absorbers, set at 5000km/s blueward of CIV 1548 emission
of the quasar.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- QSO Quasar name in J2000 format
18- 24 F7.5 --- z [1.04/4.72] CIV absorber redshift
28- 32 F5.3 0.1nm W1548 [0.05/4.23] CIV 1548 rest-frame equivalent width
36- 40 F5.3 0.1nm e_W1548 [0.001/0.2] Uncertainty in W1548
44 A1 --- l_Naod Upper limit flag for Naod
48- 53 F6.3 [cm-2] Naod [13.1/15.5] log10 Apparent Optical Depth (AOD)
column density, atoms/cm2
57- 60 F4.2 [cm-2] E_Naod [0/0.1]? Upward uncertainty in Naod (1)
64- 67 F4.2 [cm-2] e_Naod [0.01/0.2]? Downward uncertainty in Naod
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Note (1): For upper limits the uncertainty are given as as blanks.
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History:
From electronic version of the journal
References:
Hasan et al. Paper II : 2022ApJ...924...12H 2022ApJ...924...12H
(End) Prepared by [AAS], Coralie Fix [CDS], 14-Mar-2022