J/MNRAS/449/1593 CIV absorption in BAL QSOs (Baskin+, 2015)
On the origins of CIV absorption profile diversity in broad absorption line
quasars.
Baskin A., Laor A., Hamann F.
<Mon. Not. R. Astron. Soc., 449, 1593-1604 (2015)>
=2015MNRAS.449.1593B 2015MNRAS.449.1593B (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Redshifts ; Equivalent widths
Keywords: galaxies: active - quasars: absorption lines - quasars: general
Abstract:
There is a large diversity in the CIV broad absorption line (BAL)
profile among BAL quasars (BALQs). We quantify this diversity by
exploring the distribution of the CIV BAL properties, full width at
half-maximum (FWHM), maximum depth of absorption and its velocity
shift (vmd), using the Sloan Digital Sky Survey DR7 quasar
catalogue. We find the following: (i) Although the median CIV BAL
profile in the quasar rest-frame becomes broader and shallower as the
UV continuum slope (αUV at 1700-3000Å) gets bluer, the median
individual profile in the absorber rest-frame remains identical, and
is narrow (FWHM=3500km/s) and deep. Only 4 percent of BALs have
FWHM>10000km/s. (ii) As the HeII emission equivalent width (EW)
decreases, the distributions of FWHM and vmd extend to larger
values, and the median maximum depth increases. These trends are
consistent with theoretical models in which softer ionizing continua
reduce overionization, and allow radiative acceleration of faster BAL
outflows. (iii) As αUV becomes bluer, the distribution of
vmd extends to larger values. This trend may imply faster outflows
at higher latitudes above the accretion disc plane. (iv) For
non-BALQs, the CIV emission line decreases with decreasing HeII EW,
and becomes more asymmetric and blueshifted. This suggests an
increasing relative contribution of emission from the BAL outflow to
the Civ emission line as the ionizing spectral energy distribution
(SED) gets softer, which is consistent with the increasing fraction of
BALQs as the ionizing SED gets softer.
Description:
A complete description of the sample and the data analysis is provided
in Baskin et al. (2013MNRAS.432.1525B 2013MNRAS.432.1525B, BLH13).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 74 1596 Measured emission and absorption properties
--------------------------------------------------------------------------------
See also:
J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS DR7 name (JHHMMSS.ss+DDMMSS.s)
20- 29 F10.6 deg RAdeg Right ascension (J2000)
31- 39 F9.5 deg DEdeg Declination (J2000)
41- 46 F6.4 --- z Redshift from Hewett & Wild
(2010, Cat. J/MNRAS/405/2302)
48- 51 F4.1 0.1nm EWHeII Measured HeII equivalent width
53- 57 F5.2 --- alphaUV Measured between 1710 and 3000Å
(fnu∝nualpha)
59- 63 I5 km/s Vmd Velocity shift
65- 68 F4.2 --- CF CIV BAL maximum absorption depth
for HeII-EW binning (1)
70- 74 I5 km/s FWHM CIV BAL FWHM value for HeII-EW binning (1)
--------------------------------------------------------------------------------
Note (1): The values of CF and FWHM are from the HeII EW binning of the median
non-BALQ emission. Binning by alphaUV yields nearly identical results
(see text).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Nov-2015