J/MNRAS/450/3904 Quasars narrow absorption lines from SDSS (Chen+, 2015)
Narrow absorption lines with two observations from the Sloan Digital Sky Survey.
Chen Z.-F., Gu Q.-S., Chen Y.-M., Cao Y.
<Mon. Not. R. Astron. Soc., 450, 3904-3919 (2015)>
=2015MNRAS.450.3904C 2015MNRAS.450.3904C (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Photometry, SDSS ; Redshifts ; Equivalent widths
Keywords: catalogues - surveys - quasars: absorption lines - quasars: general
Abstract:
We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with
repeated observations to search for variations of the narrow
C IV λλ1548, 1551 and Mg II λλ2796, 2803
absorption doublets in spectral regions shortward of 7000Å in the
observed frame, which corresponds to time-scales of about 150-2643d
in the quasar rest frame. In these quasar spectra, we detect 3580 CIV
absorption systems with zabs=1.5188-3.5212 and 1809 MgII absorption
systems with zabs=0.3948-1.7167. In term of the absorber velocity
(β) distribution in the quasar rest frame, we find a substantial
number of CIV absorbers with β<0.06, which might be connected to
absorption of quasar outflows. The outflow absorption peaks at
υ∼2000km/s and drops rapidly below this peak value. Among 3580
CIV absorption systems, 52 systems (∼1.5 percent) show obvious
variations in equivalent widths in the absorber rest frame (Wr):
16 enhanced, 16 emerged, 12 weakened and 8 disappeared systems,
respectively. We find that changes in Wrλ1548 are related neither
to the time-scales of the two SDSS observations nor to absorber velocities
in the quasar rest frame. Variable absorption in low-ionization
species is important to constrain the physical conditions of the
absorbing gas. There are two variable MgII absorption systems measured
from SDSS spectra detected by Hacker et al. (2013, J/MNRAS/434/163).
However, in our MgII absorption sample, we find that neither shows
variable absorption with confident levels of >4σ for λ2796
lines and >3σ for λ2803 lines.
Description:
The Baryon Oscillation Spectroscopic Survey (BOSS: Eisenstein et al.
2011AJ....142...72E 2011AJ....142...72E; Paris et al. 2012, Cat. VII/269) is the main
dark-time legacy survey of the third stage of the SDSS, which used the
same 2.5-m telescope (Gunn et al. 2006AJ....131.2332G 2006AJ....131.2332G; Ross et al. 2012,
J/ApJS/199/3) as the first and second stages of the SDSS (hereafter
SDSS-I/II). SDSS-I/II spectra have a wavelength coverage from 3800-9200Å
with a spectral resolution of 1800-2200 (e.g. York et al.
2000AJ....120.1579Y 2000AJ....120.1579Y). BOSS spectra span a range from 3600-10500Å at
a resolution of 1300-2500 (Paris et al. 2012, Cat. VII/269). During the
first two years, BOSS detected 87822 quasars over an area of 3275 deg2,
including 7932 quasars that were observed by SDSS-I/II as well. Quasars
observed by both SDSS-I/II and BOSS provide a remarkable chance to study
the variabilities of absorption lines in a large population.
Throughout this work, we take the quasar emission redshifts provided
by Hewett & Wild (2010, J/MNRAS/405/2302,
http://das.sdss.org/va/Hewett_Wild_dr7qso_newz/) directly.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 104 3580 Catalog of C IV λλ1548, 1551
Absorption Systems
tablea2.dat 104 1808 Catalog of Mg II λλ2796, 2803
Absorption Systems
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See also:
VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
J/ApJ/613/129 : Equivalent widths of QSOs (Wise+, 2004)
J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)
J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)
J/MNRAS/434/163 : QSOs narrow absorption line variability (Hacker+, 2013)
J/ApJS/210/7 : BOSS narrow CIV absorption lines. I. zem≤2.4 (Chen+, 2014)
J/ApJS/215/12 : BOSS narrow CIV absorption lines. II. zem>2.4 (Chen+, 2014)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS identifier (HHMMSS.ss+DDMMSS.s)
20- 25 F6.4 --- zem Redshift derived from emission lines
27- 32 F6.4 --- zabs Redshift derived from absorption lines
34- 37 I4 --- Plate-S SDSS-I/II plate identifier
39- 43 I5 d MJD-S Modified Julian Date of the observation
45- 48 I4 --- Fiber-S SDSS-I/II fiber identifier
50- 53 F4.2 0.1nm EW1548-S SDSS-I/II Rest equivalent width of
C IV 1548Å (G1)
55- 58 F4.2 0.1nm e_EW1548-S SDSS-I/II EW1548-S divided by its 1σ
error
60- 63 F4.2 0.1nm EW1551-S SDSS-I/II Rest equivalent width of
C IV 1551Å (G1)
65- 68 F4.2 0.1nm e_EW1551-S SDSS-I/II EW1551-S divided by its 1σ
error
70- 73 I4 --- Plate-B BOSS plate identifier
75- 79 I5 d MJD-B Modified Julian Date of the observation
81- 84 I4 --- Fiber-B BOSS fiber identifier
86- 89 F4.2 0.1nm EW1548-B BOSS Rest equivalent width of C IV 1548Å
(G1)
91- 94 F4.2 0.1nm e_EW1548-B BOSS EW1548-B divided by its 1σ error
96- 99 F4.2 0.1nm EW1551-B BOSS Rest equivalent width of C IV 1551Å
(G1)
101-104 F4.2 0.1nm e_EW1551-B BOSS EW1551-B divided by its 1σ error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS identifier (HHMMSS.ss+DDMMSS.s)
20- 25 F6.4 --- zem Redshift derived from emission lines
27- 32 F6.4 --- zabs Redshift derived from absorption lines
34- 37 I4 --- Plate-S SDSS-I/II plate identifier
39- 43 I5 d MJD-S Modified Julian Date of the observation
45- 48 I4 --- Fiber-S SDSS-I/II fiber identifier
50- 53 F4.2 0.1nm EW2796-S SDSS-I/II Rest equivalent width of
Mg II 2796Å (G1)
55- 58 F4.2 0.1nm e_EW2796-S SDSS-I/II EW2796-S divided by its 1σ
error
60- 63 F4.2 0.1nm EW2803-S SDSS-I/II Rest equivalent width of
Mg II 2803Å (G1)
65- 68 F4.2 0.1nm e_EW2803-S SDSS-I/II EW2803-S divided by its 1σ
error
70- 73 I4 --- Plate-B SDSS-III plate identifier
75- 79 I5 d MJD-B Modified Julian Date of the observation
81- 84 I4 --- Fiber-B BOSS fiber identifier
86- 89 F4.2 0.1nm EW2796-B BOSS Rest equivalent width of Mg II 2796Å
(G1)
91- 94 F4.2 0.1nm e_EW2796-B BOSS EW2796-B divided by its 1σ error
96- 99 F4.2 0.1nm EW2803-B BOSS Rest equivalent width of Mg II 2803Å
(G1)
101-104 F4.2 0.1nm e_EW2803-B BOSS EW2803-B divided by its 1σ error
--------------------------------------------------------------------------------
Global notes:
Note (G1): In units of Angstroms.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 13-Dec-2017