Compact stellar systems in the Fornax Cluster: Super-massive star clusters or extremely compact dwarf galaxies?

被引:221
作者
Drinkwater, MJ [1 ]
Jones, JB
Gregg, MD
Phillipps, S
机构
[1] Univ Melbourne, Sch Phys, Melbourne, Vic 3010, Australia
[2] Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England
[3] Univ Calif Davis, Livermore, CA 94550 USA
[4] Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA
来源
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA | 2000年 / 17卷 / 03期
关键词
galaxies : star clusters; alaxies : dwarf; galaxies : formation;
D O I
10.1071/AS00034
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We describe a population of compact objects in the centre of the Fornax Cluster which were discovered as part of our 2dF Fornax Spectroscopic Survey. These objects have spectra typical of old stellar systems, but are unresolved on photographic sky survey plates. They have absolute magnitudes - 13 < M(B) <-11 so they are 10 times more luminous than any Galactic globular clusters. but fainter than any known compact dwarf galaxies. These objects are all within 30 arcminutes of the central galaxy of the cluster, NGC 1399. but are distributed over larger radii than the globular cluster system of that galaxy. We suggest that these objects are either super-massive star clusters (intra-cluster globular clusters or tidally stripped nuclei of dwarf galaxies) or a new type of low-luminosity, compact elliptical dwarf ('M32-type') galaxy. The best way to test these hypotheses will be To obtain high-resolution imaging and high-dispersion spectroscopy to determine their structures and mass-to-light ratios. This will allow us to compare them to known compact objects and establish whether they represent a new class of hitherto unknown stellar system.
引用
收藏
页码:227 / 233
页数:7
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