SERENDIPITOUS DISCOVERY OF A MASSIVE cD GALAXY AT z=1.096: IMPLICATIONS FOR THE EARLY FORMATION AND LATE EVOLUTION OF cD GALAXIES

	SERENDIPITOUS DISCOVERY OF A MASSIVE cD GALAXY AT z=1.096: IMPLICATIONS FOR THE EARLY FORMATION AND LATE EVOLUTION OF cD GALAXIES
	Liu, F. S.1,2; Guo, Yicheng 2; Koo, David C.2; Trump, Jonathan R.2; Barro, Guillermo 2; Yesuf, Hassen 2; Faber, S. M.2; Giavalisco, M.3; Cassata, P.4; Koekemoer, A. M.5
刊名	ASTROPHYSICAL JOURNAL
	2013-06-01
卷号	769 期号:2
关键词	galaxies: clusters: general galaxies: elliptical and lenticular, cD galaxies: evolution
英文摘要	We have made a serendipitous discovery of a massive (similar to 5 x 10(11)M(circle dot)) cD galaxy at z = 1.096 in a candidate-rich cluster in the Hubble Ultra Deep Field (HUDF) area of GOODS-South. This brightest cluster galaxy (BCG) is the most distant cD galaxy confirmed to date. Ultra-deep HST/WFC3 images reveal an extended envelope starting from similar to 10 kpc and reaching similar to 70 kpc in radius along the semimajor axis. The spectral energy distributions indicate that both its inner component and outer envelope are composed of an old, passively evolving (specific star formation rate < 10-4 Gyr(-1)) stellar population. The cD galaxy lies on the same mass-size relation as the bulk of quiescent galaxies at similar redshifts. The cD galaxy has a higher stellar mass surface density (similar to M-/R-50(2)) but a similar velocity dispersion (similar to root M-/R-50) to those of more massive, nearby cDs. If the cD galaxy is one of the progenitors of today's more massive cDs, its size (R-50) and stellar mass have had to increase on average by factors of 3.4 +/- 1.1 and 3.3 +/- 1.3 over the past similar to 8 Gyr, respectively. Such increases in size and stellar mass without being accompanied by significant increases in velocity dispersion are consistent with evolutionary scenarios driven by both major and minor dissipationless (dry) mergers. If such cD envelopes originate from dry mergers, our discovery of even one example proves that some BCGs entered the dry merger phase at epochs earlier than z = 1. Our data match theoretical models which predict that the continuance of dry mergers at z < 1 can result in structures similar to those of massive cD galaxies seen today. Moreover, our discovery is a surprise given that the extreme depth of the HUDF is essential to reveal such an extended cD envelope at z > 1 and, yet, the HUDF covers only a minuscule region of sky (similar to 3.1 x 10(-8)). Adding that cDs are rare, our serendipitous discovery hints that such cDs may be more common than expected, perhaps even ubiquitous. Images reaching HUDF depths of more area (especially with cluster BCGs at z > 1) are needed to confirm this conjecture.
收录类别	SCI
语种	英语
WOS记录号	WOS:000319999100063
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/5990]
专题	国家天文台_星系宇宙学研究部
作者单位	1.Shenyang Normal Univ, Coll Phys Sci & Technol, Shenyang 110034, Peoples R China 2.Univ Calif Santa Cruz, Dept Astron & Astrophys, Lick Observ, UCO, Santa Cruz, CA 95064 USA 3.Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA 4.Aix Marseille Univ, CNRS, LAM, F-13388 Marseille, France 5.Space Telescope Sci Inst, Baltimore, MD 21218 USA 6.Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, RM, Italy 7.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 8.Tianjin Normal Univ, Tianjin Astrophys Ctr, Tianjin 300387, Peoples R China 9.Observ Carnegie Inst Sci, Pasadena, CA 91101 USA 10.Johns Hopkins Univ, Baltimore, MD 21218 USA
推荐引用方式 GB/T 7714	Liu, F. S.,Guo, Yicheng,Koo, David C.,et al. SERENDIPITOUS DISCOVERY OF A MASSIVE cD GALAXY AT z=1.096: IMPLICATIONS FOR THE EARLY FORMATION AND LATE EVOLUTION OF cD GALAXIES[J]. ASTROPHYSICAL JOURNAL,2013,769(2).
APA	Liu, F. S..,Guo, Yicheng.,Koo, David C..,Trump, Jonathan R..,Barro, Guillermo.,...&Wuyts, Stijn.(2013).SERENDIPITOUS DISCOVERY OF A MASSIVE cD GALAXY AT z=1.096: IMPLICATIONS FOR THE EARLY FORMATION AND LATE EVOLUTION OF cD GALAXIES.ASTROPHYSICAL JOURNAL,769(2).
MLA	Liu, F. S.,et al."SERENDIPITOUS DISCOVERY OF A MASSIVE cD GALAXY AT z=1.096: IMPLICATIONS FOR THE EARLY FORMATION AND LATE EVOLUTION OF cD GALAXIES".ASTROPHYSICAL JOURNAL 769.2(2013).