The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851

Authors

A. P. Milone, Universita di Padova
L. R. Bedin, Space Telescope Science InstituteFollow
G. Piotto, Universita di Padova
J. Anderson, Rice UniversityFollow
I. R. King, University of Washington
A. Sarajedini, University of Florida
A. Dotter, Dartmouth College
B. Chaboyer, Dartmouth CollegeFollow
A. Marin Franch, Instituto de Astrofisica de Canarias
S. Majewski, University of Virginia
A. Aparicio, Instituto de Astrofisica de CanariasFollow
M. Hempel, University of Florida
N. E.Q Paust, Space Telescope Science Institute
I. N. Reid, Space Telescope Science Institute
A. Rosenberg, Instituto de Astrofisica de Canarias
M. Siegel, University of Texas at Austin

Document Type

Article

Publication Date

9-21-2008

Publication Title

Letters of the Astrophysical Journal

Abstract

Photometry with the Hubble Space Telescope Advanced Camera for Surveys (HST ACS) 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 ~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.

DOI

10.1086/524188

Dartmouth Digital Commons Citation

Milone, A. P.; Bedin, L. R.; Piotto, G.; Anderson, J.; King, I. R.; Sarajedini, A.; Dotter, A.; Chaboyer, B.; Marin Franch, A.; Majewski, S.; Aparicio, A.; Hempel, M.; Paust, N. E.Q; Reid, I. N.; Rosenberg, A.; and Siegel, M., "The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851" (2008). Dartmouth Scholarship. 3296.
https://digitalcommons.dartmouth.edu/facoa/3296