揭开帕洛玛2：银河外 halo 中最隐蔽的星团
摘要
We present the first color-magnitude study for Palomar 2, a distant and heavily obscured globular cluster near the Galactic anticenter. Our (V,V-I) color-magnitude diagram (CMD), obtained with the UH8K camera at the CFHT, reaches V(lim) = 24 and clearly shows the principal sequences of the cluster, though with substantial overall foreground absorption and differential reddening. The CMD morphology shows a well populated red horizontal branch with a sparser extension to the blue, similar to clusters such as NGC 1261, 1851, or 6229 with metallicities near [Fe/H] = -1.3, placing it about 34 kpc from the Galactic center. We use starcounts of the bright stars to measure the core radius, half-mass radius, and central concentration of the cluster. Its integrated luminosity is M_V = -7.9, making it clearly brighter and more massive than most other clusters in the outer halo.
引用
@article{arxiv.astro-ph/9707049,
title = {Unveiling Palomar 2: The Most Obscure Globular Cluster in the Outer Halo},
author = {W. E. Harris and P. R. Durrell and G. R. Petitpas and T. M. Webb and S. C. Woodworth},
journal= {arXiv preprint arXiv:astro-ph/9707049},
year = {2009}
}
备注
25 pages, aastex, with 8 postscript figures; accepted for publication in AJ, September 1997. Also available by e-mail from [email protected]. Please consult Harris directly for (big) postscript files of Figures 1a,b (the images of the cluster)