J/ApJ/777/168 CIV and SiIV broad absorption line troughs in SDSS (Filiz+, 2013)
Broad absorption line variability on multi-year timescales in a large
quasar sample.
Filiz Ak N., Brandt W.N., Hall P.B., Schneider D.P., Anderson S.F.,
Hamann F., Lundgren B.F., Myers A.D., Paris I., Petitjean P., Ross N.P.,
Shen Y., York D.
<Astrophys. J., 777, 168 (2013)>
=2013ApJ...777..168F 2013ApJ...777..168F (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Redshifts ; Equivalent widths ; Spectroscopy
Keywords: quasars: absorption lines
Abstract:
We present a detailed investigation of the variability of 428 CIV and
235 SiIV broad absorption line (BAL) troughs identified in multi-epoch
observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III.
These observations primarily sample rest-frame timescales of 1-3.7yr
over which significant rearrangement of the BAL wind is expected. We
derive a number of observational results on, e.g., the frequency of
BAL variability, the velocity range over which BAL variability occurs,
the primary observed form of BAL-trough variability, the dependence of
BAL variability upon timescale, the frequency of BAL strengthening
versus weakening, correlations between BAL variability and BAL-trough
profiles, relations between CIV and SiIV BAL variability, coordinated
multi-trough variability, and BAL variations as a function of quasar
properties. We assess implications of these observational results for
quasar winds. Our results support models where most BAL absorption is
formed within an order-of-magnitude of the wind-launching radius,
although a significant minority of BAL troughs may arise on larger
scales. We estimate an average lifetime for a BAL trough along our
line-of-sight of a few thousand years. BAL disappearance and emergence
events appear to be extremes of general BAL variability, rather than
being qualitatively distinct phenomena. We derive the parameters of a
random-walk model for BAL EW variability, finding that this model can
acceptably describe some key aspects of EW variability. The
coordinated trough variability of BAL quasars with multiple troughs
suggests that changes in "shielding gas" may play a significant role
in driving general BAL variability.
Description:
We have utilized data from the Sloan Digital Sky Survey-I/II (York et
al. 2000AJ....120.1579Y 2000AJ....120.1579Y) and BOSS that use a mosaic CCD camera plus
multi-object spectrograph on a dedicated 2.5m telescope at Apache
Point Observatory. Between 2000-2008, the SDSS I/II completed
spectroscopy over 9380deg2 and obtained over 1.6 million spectra in
total, including more than 105000 quasars. Using an improved
spectrograph, BOSS spectra have coverage between 3600-10000Å at a
resolution of 1300-3000 (see Dawson et al. 2013AJ....145...10D 2013AJ....145...10D; Smee
et al. 2013AJ....146...32S 2013AJ....146...32S).
We have studied the variability of CIV and SiIV BAL troughs using a
systematically observed sample of 291 BAL quasars. We have utilized
699 high-quality spectra of these quasars obtained by SDSS-I/II and
BOSS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
qsos.dat 24 291 List of QSOs (table added by CDS)
table2.dat 294 510 CIV BAL troughs for 291 quasars
table3.dat 294 291 SiIV BAL troughs for 181 quasars
table4.dat 91 923 CIV BAL-trough variable regions for 232 QSOs
table5.dat 91 308 SiIV BAL-trough variable regions for 108 QSOs
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See also:
VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VII/252 : SDSS-DR5 quasar catalog (Schneider+, 2007)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJS/215/12 : BOSS narrow CIV absorption lines. II. zem>2.4 (Chen+, 2014)
J/ApJS/210/7 : BOSS narrow CIV absorption lines. I. zem≤2.4 (Chen+, 2014)
J/ApJ/763/37 : SDSS QSO metals. I. 1.5<z<4.5 CIV absorbers (Cooksey+, 2013)
J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/ApJ/729/87 : SiIV absorption systems (Cooksey+, 2011)
J/MNRAS/410/860 : Redshift dependence of BAL QSOs (Allen+, 2011)
J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)
J/MNRAS/399/2231 : SDSS DR5 BALQSO catalog (Scaringi+, 2009)
J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)
J/ApJ/680/169 : SDSS DR5 virial black hole masses (Shen+, 2008)
J/ApJ/665/990 : SDSS DR2 BAL QSOs (Ganguly+, 2007)
J/ApJ/641/78 : CIV variability in 105 SDSS quasars (Wilhite+, 2006)
J/ApJS/165/1 : BAL QSOs from SDSS DR3 (Trump+, 2006)
J/AJ/125/1711 : Broad Absorption Line Quasars from SDSS (Reichard+, 2003)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: qsos.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS QSO identification; JHHMMSS.ss+DDMMSS.s
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Byte-by-byte Description of file: table[23].dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- BID BAL trough identifier (G1)
6- 24 A19 --- SDSS QSO identification; JHHMMSS.ss+DDMMSS.s
26- 34 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
36- 43 F8.5 deg DEdeg Declination in decimal degrees (J2000)
45- 50 F6.4 --- z [2/4] Redshift
52- 58 F7.5 --- e_z [0.0002/0.003] Error in z
60 I1 --- L [0/1] 1=LoBAL (low ionization BAL) flag
62 I1 --- T [0/1] 1=timescale>1yr (2)
64- 67 I4 --- Plate1 First-epoch spectrum plate number
69- 73 I5 d MJD1 First-epoch Modified Julian observation Date
75- 77 I3 --- Fib1 First-epoch spectrum fiber number
79- 83 F5.2 --- SN1 [10/40] Signal-to-noise at 1700Å
for the first-epoch spectrum
85- 88 I4 --- Plate2 Second-epoch spectrum plate number
90- 94 I5 d MJD2 Second-epoch Modified Julian observation Date
96- 98 I3 --- Fib2 Second-epoch spectrum fiber number
100-104 F5.2 --- SN2 [10/60] Signal-to-noise at 1700Å
for the second-epoch spectrum
106-113 F8.3 d dt [0.2/1353] Rest-frame timescale between
the two observations
115-122 F8.1 km/s Vmax [-30000/-5074] Maximum (blue-edge) velocity
of BAL trough
124-131 F8.1 km/s Vmin [-27395/-3000] Minimum (red-edge) velocity
of BAL trough
133-140 F8.1 km/s Vc1 [-28841/-4074] First-epoch centroid velocity
of the BAL trough
142-149 F8.1 km/s Vc2 [-28725/-4166] Second-epoch centroid velocity
of the BAL trough
151-155 F5.2 --- d1 [-0.03/1] First-epoch average BAL trough depth
157-160 F4.2 --- e_d1 [0/1] Error in d1
162-165 F4.1 --- d2 [0/1] Second-epoch average BAL trough depth
167-170 F4.2 --- e_d2 [0/1] Error in d2
172-176 F5.2 0.1nm EW1 First-epoch CIV/SiIV equivalent width (Å)
178-181 F4.2 0.1nm e_EW1 Error in EW1
183-188 F6.3 0.1nm EW2 Second-epoch CIV/SiIV equivalent width (Å)
190-195 F6.4 0.1nm e_EW2 Error in EW2
197-202 F6.2 0.1nm DEW Equivalent width variation ΔEW=EW2-EW1
204-208 F5.3 0.1nm e_DEW Error in DEW
210-214 F5.2 --- fEW [-2/2] Fractional equivalent width variation
ΔEW/ = 2(EW2-EW1)/(EW2+EW1)
216-220 F5.3 --- e_fEW Error in fEW
222-223 I2 --- Nv [0/14] Number of variable regions detected
in BAL trough
225-231 F7.1 km/s Sum [0/10960] Total width of the variable regions
233-237 F5.3 --- fDV [0/1] Ratio fΔV of total variable
region width and the BAL trough width
239-248 A10 --- xBAL Corresponding SiIV/CIV BAL Trough IDs as
given in Table 3 or Table 2 (3)
250-255 F6.3 [10-7W] logLb Log of Quasar bolometric luminosity (erg/s)
257-260 F4.2 [10-7W] e_logLb Error in logLb
262-266 F5.2 [Msun] logM ?=0 Log of black-hole mass
268-272 F5.2 [Msun] e_logM ?=-1 Error in logM
274-281 F8.3 [-] logLe [-1.7/0.8]?=-999 log of luminosity to i
Eddington luminosity ratio
283-288 F6.2 mag iMag [-29.8/-26.7] Absolute i-band magnitude
290-294 F5.1 --- R [1/598]?=-1 Radio-loudness parameter
(R=F6cm/F2500Å)
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Note (2): 1 for timescales of more than 1yr (Δt(min,1)), 0 otherwise.
Note (3): As explained in Section 4.6, we search for accompanying CIV BAL
troughs for SiIV troughs with -3000>Vcent>-13000km/s. We found
that five SiIV troughs, S3, S13, S201, S202, and S237, have an
accompanying CIV trough that does not satisfy our BAL-trough
identification criteria.
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Byte-by-byte Description of file: table[45].dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- VID Variable region identifier (G1)
7- 25 A19 --- SDSS QSO identification; JHHMMSS.ss+DDMMSS.s
27- 31 I5 d MJD1 Modified Julian date of first-epoch observation
33- 37 I5 d MJD2 Modified Julian date of second-epoch observation
39- 42 A4 --- BID CIV BAL/SiIV BAL trough ID as given in
Table 2/Table 3
44- 51 F8.1 km/s Vb.max [-30000/-5074] Maximum (blue-edge) velocity of
BAL trough
53- 60 F8.1 km/s Vb.min [-27395/-3000] Minimum (red-edge) velocity of
BAL trough
62- 69 F8.1 km/s Vv.max [-29977/-3321] Maximum (blue-edge) velocity of
variable region
71- 78 F8.1 km/s Vv.min [-29531/-3018] Minimum (red-edge) velocity of
variable region
80- 85 F6.1 km/s dVr [273/7861] Width of variable region
87- 91 F5.2 --- Vnrt [-1.5/1.2] Normalized relative velocity
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Global Notes:
Note (G1): Identifiers are
* CNNN for CIV BAL troughs (table2); NNN between 1 and 510
* SNNN for SiV BAL troughs (table3); NNN between 1 and 291
* CVNNN for CIV BAL variabler regions (table4); NNN between 1 and 923
* SVNNN for SiIV BAL variabler regions (table4); NNN between 1 and 308
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Apr-2015