The ACS survey of galactic globular clusters. III. The double subgiant branch of NGC 1851

被引：239

作者：

Milone, A. P. ^{[1
]}

Bedin, L. R. ^{[2
]}

Piotto, G. ^{[1
]}

Anderson, J. ^{[3
]}

King, I. R. ^{[4
]}

Sarajedini, A. ^{[5
]}

Dotter, A. ^{[6
]}

Chaboyer, B. ^{[6
]}

Marin-Franch, A. ^{[7
]}

Majewski, S. ^{[8
]}

Aparicio, A. ^{[7
]}

Hempel, M. ^{[5
]}

Paust, N. E. Q. ^{[2
]}

Reid, I. N. ^{[2
]}

Rosenberg, A. ^{[7
]}

Siegel, M. ^{[9
]}

机构：

[1] Univ Padua, Dept Astron, I-35122 Padua, Italy

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

[3] Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA

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

[5] Univ Florida, Dept Astron, Bryant Space Sci Ctr 211, Gainesville, FL 32611 USA

[6] Dartmouth Coll, Dept Phys & Astron, Willard Labs 6127, Hanover, NH 03755 USA

[7] Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Canary Isl, Spain

[8] Univ Virginia, Dept Astron, Charlottesville, VA 22904 USA

[9] Univ Texas Austin, McDonald Observ, Austin, TX 78712 USA

来源：

ASTROPHYSICAL JOURNAL | 2008年 / 673卷 / 01期

关键词：

globular clusters : individual (NGC 1851); Hertzsprung-Russell diagram;

D O I：

10.1086/524188

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Photometry with the Hubble Space Telescope Advanced Camera for Surveys (HSTACS) reveals that the subgiant branch (SGB) of the globular cluster NGC 1851 splits into two well-defined branches. If the split is due only to an age effect, the two SGBs would imply two star formation episodes separated by similar to 1 Gyr. We discuss other anomalies in NGC 1851 that could be interpreted in terms of a double stellar population. Finally, we compare the case of NGC 1851 with the other two globulars known to host multiple stellar populations, and show that all three clusters differ in several important respects.

引用

页码：241 / 250

页数：10

共 33 条

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