|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'503'724
Articles rated: 2609
23 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Low-z MgII Broad Absorption-Line Quasars from the Sloan Digital Sky Survey | | Shaohua Zhang
; Ting-Gui Wang
; Huiyuan Wang
; Hongyan Zhou
; Xiao-Bo~Dong
; Jian-Guo Wang
; | | Date: |
2 Apr 2010 | | Abstract: | We present a sample of 68 low-z MgII low-ionization broad absorption-line
(loBAL) quasars. The sample is uniformly selected from the SDSS5 according to
the following criteria: (1) 0.4<z<0.8, (2) median S/N>7, and (3) MgII
absorption-line width > 1600 kms. The last criterion is a trade-off between
the completeness and consistency with respect to the canonical definition of
BAL quasars that have the ’balnicity index’ BI>0 in CIV BAL. We adopted such a
criterion to ensure that ~90% of our sample are classical BAL quasars and the
completeness is ~80%, based on extensive tests using high-z quasar samples with
measurements of both CIV and MgII BALs. We found (1) MgII BAL is more
frequently detected in quasars with narrower Hbeta emission-line, weaker [OIII]
emission-line, stronger optical FeII multiplets and higher luminosity. In term
of fundamental physical parameters of a black hole accretion system, loBAL
fraction is significantly higher in quasars with a higher Eddington ratio than
those with a lower Eddington ratio. The fraction is not dependent on the black
hole mass in the range concerned. The overall fraction distribution is broad,
suggesting a large range of covering factor of the absorption material. (2)
[OIII]-weak loBAL quasars averagely show undetected [NeV] emission line and a
very small line ratio of [NeV] to [OIII]. However, the line ratio in non-BAL
quasars, which is much larger than that in [OIII]-weak loBAL quasars, is
independent of the strength of the [OIII] line. (3) loBAL and non-loBAL quasars
have similar colors in near-infrared to optical band but different colors in
ultraviolet. (4) Quasars with MgII absorption lines of intermediate width are
indistinguishable from the non-loBAL quasars in optical emission line
properties but their colors are similar to loBAL quasars, redder than non-BAL
quasars. We also discuss the implication of these results. | | Source: | arXiv, 1004.0299 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER