The enrichment history of hot gas in poor galaxy groups

被引:45
作者
Davis, DS
Mulchaey, JS
Mushotzky, RF
机构
[1] MIT, Ctr Space Res NE80 6003, Cambridge, MA 02139 USA
[2] Carnegie Inst Washington Observ, Pasadena, CA 91101 USA
[3] NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA
关键词
dark matter; galaxies : ISM; intergalactic medium; X-rays : galaxies;
D O I
10.1086/306665
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have analyzed the ASCA SIS and GIS data for 17 groups and determined the average temperature and abundance of the hot X-ray-emitting gas. For groups with gas temperatures less than 1.5 keV, we find that the abundance is correlated with the gas temperature and luminosity. We have also determined the abundance of the alpha-elements and iron independently for those groups with sufficient counts. We find that for the cool groups (i.e., kT < 1.5 keV) the ratio of alpha-elements to iron is similar to 1, which is about half that seen in clusters. Spectral fits with the S, Si, and Fe abundances allowed to vary separately suggest the S/Fe ratio is similar to that seen in clusters, while the Si/Fe ratio in groups is half the value determined for richer systems. The mass of metals per unit of blue luminosity drops rapidly in groups as the temperature drops. There are two possible explanations for this decrease. One is that the star formation in groups is very different from that in rich clusters. The other explanation is that groups lose much of their enriched material via winds during the early evolution of ellipticals. If the latter is true, we find that poor groups will have contributed significantly (roughly one-third of the metals) to the enrichment of the intergalactic medium.
引用
收藏
页码:34 / 40
页数:7
相关论文
共 36 条
[31]   Iron as a tracer in galaxy clusters and groups [J].
Renzini, A .
ASTROPHYSICAL JOURNAL, 1997, 488 (01) :35-43
[32]  
SCHARF CA, 1997, APJ, V485, P665
[33]   THE METAL ABUNDANCE AND SPECIFIC ENERGY OF INTRACLUSTER GAS [J].
WHITE, RE .
ASTROPHYSICAL JOURNAL, 1991, 367 (01) :69-77
[34]   THE EVOLUTION AND EXPLOSION OF MASSIVE STARS .2. EXPLOSIVE HYDRODYNAMICS AND NUCLEOSYNTHESIS [J].
WOOSLEY, SE ;
WEAVER, TA .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1995, 101 (01) :181-235
[35]  
WYSE RFG, 1998, IN PRESS APJL
[36]   The properties of poor groups of galaxies. I. Spectroscopic survey and results [J].
Zabludoff, AI ;
Mulchaey, JS .
ASTROPHYSICAL JOURNAL, 1998, 496 (01) :39-72