中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Low-z mg ii broad absorption-line quasars from the sloan digital sky survey

文献类型:期刊论文

作者Zhang, Shaohua1,2; Wang, Ting-Gui1,2; Wang, Huiyuan1,2; Zhou, Hongyan1,2; Dong, Xiao-Bo1,2; Wang, Jian-Guo3,4,5
刊名Astrophysical journal
出版日期2010-05-01
卷号714期号:1页码:367-383
ISSN号0004-637X
关键词Galaxies: active Quasars: absorption lines Quasars: emission lines Quasars: general
DOI10.1088/0004-637x/714/1/367
通讯作者Zhang, shaohua(zsh@mail.ustc.edu.cn)
英文摘要We present a sample of 68 low-z mg ii low-ionization broad absorption-line (lobal) quasars. the sample is uniformly selected from the sloan digital sky survey data release 5 according to the following criteria: (1) redshift 0.4 < z less than or similar to 0.8, (2) median spectral s/n > 7 pixel(-1), and (3) mg ii absorption-line width delta upsilon(c) >= 1600 km s(-1). 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 c iv bal. we adopted such a criterion to ensure that similar to 90% of our sample are classical bal quasars and the completeness is similar to 80%, based on extensive tests using high-z quasar samples with measurements of both c iv and mg ii bals. we found (1) mg ii bal is more frequently detected in quasars with narrower h beta emission line, weaker [o iii] emission line, stronger optical fe ii 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) [o iii]-weak lobal quasars averagely show undetected [ne v] emission line and a very small line ratio of [ne v] to [o iii]. however, the line ratio in non-bal quasars, which is much larger than that in [o iii]-weak lobal quasars, is independent of the strength of the [o iii] 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.
WOS关键词ACTIVE GALACTIC NUCLEI ; BLACK-HOLE MASSES ; SPECTRAL ENERGY-DISTRIBUTIONS ; EMISSION-LINE ; X-RAY ; STELLAR OBJECTS ; DATA RELEASE ; REDDENED QUASARS ; PHYSICAL-PROPERTIES ; INTRINSIC FRACTION
WOS研究方向Astronomy & Astrophysics
WOS类目Astronomy & Astrophysics
语种英语
出版者IOP PUBLISHING LTD
WOS记录号WOS:000276701000030
URI标识http://www.irgrid.ac.cn/handle/1471x/2413618
专题中国科学院大学
通讯作者Zhang, Shaohua
作者单位1.Chinese Acad Sci, Univ Sci & Technol China, Key Lab Res Galaxies & Cosmol, Hefei 230026, Anhui, Peoples R China
2.Univ Sci & Technol China, Ctr Astrophys, Hefei 230026, Anhui, Peoples R China
3.Chinese Acad Sci, Yunnan Observ, Natl Astron Observ, Kunming 650011, Yunnan, Peoples R China
4.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
5.Chinese Acad Sci, Lab Struct & Evolut Celestial Bodies, Kunming 650011, Peoples R China
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GB/T 7714
Zhang, Shaohua,Wang, Ting-Gui,Wang, Huiyuan,et al. Low-z mg ii broad absorption-line quasars from the sloan digital sky survey[J]. Astrophysical journal,2010,714(1):367-383.
APA Zhang, Shaohua,Wang, Ting-Gui,Wang, Huiyuan,Zhou, Hongyan,Dong, Xiao-Bo,&Wang, Jian-Guo.(2010).Low-z mg ii broad absorption-line quasars from the sloan digital sky survey.Astrophysical journal,714(1),367-383.
MLA Zhang, Shaohua,et al."Low-z mg ii broad absorption-line quasars from the sloan digital sky survey".Astrophysical journal 714.1(2010):367-383.

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来源:中国科学院大学

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