Chandra observation of the globular cluster NGC 6440 and the nature of cluster X-ray luminosity functions

被引：75

作者：

Pooley, D ^{[1
]}

Lewin, WHG

Verbunt, F

Homer, L

Margon, B

Gaensler, BM

Kaspi, VM

Miller, JM

Fox, DW

van der Klis, M

机构：

[1] MIT, Ctr Space Res, Cambridge, MA 02139 USA

[2] MIT, Dept Phys, Cambridge, MA 02139 USA

[3] Univ Utrecht, Inst Astron, NL-3508 TA Utrecht, Netherlands

[4] Univ Washington, Dept Astron, Seattle, WA 98195 USA

[5] Space Telescope Sci Inst, Baltimore, MD 21218 USA

[6] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[7] McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada

[8] CALTECH, Dept Astron, Pasadena, CA 91125 USA

[9] Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands

[10] Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands

来源：

ASTROPHYSICAL JOURNAL | 2002年 / 573卷 / 01期

关键词：

binaries : close; globular clusters : individual (NGC 6440); novae cataclysmic variables; stars : neutron;

D O I：

10.1086/340498

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

As part of our campaign to determine the nature of the various source populations of the low-luminosity globular cluster X-ray sources, we have obtained a Chandra X-Ray Observatory ACIS-S3 image of the globular cluster NGC 6440. We detect 24 sources to a limiting luminosity of similar to2 x 10(31) ergs s(-1) (0.5-2.5 keV) inside the cluster's half-mass radius, all of which lie within 2 core radii of the cluster center. We also find excess emission in and around the core that could be due to unresolved point sources. Based on X-ray luminosities and colors, we conclude that there are 4-5 likely quiescent low-mass X-ray binaries and that most of the other sources are cataclysmic variables. We compare these results to Chandra results from other globular clusters and find the X-ray luminosity functions differ among the clusters.

引用

页码：184 / 190

页数：7

共 34 条

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