Structural Parameters of the M87 Globular Clusters
Abstract
We derive structural parameters for ~2000 globular clusters in the giant Virgo elliptical M87 using extremely deep Hubble Space Telescope images in F606W (V) and F814W (I) taken with the ACS/WFC. The cluster scale sizes (half-light radii r_h) and ellipticities are determined from PSF-convolved King-model profile fitting. We find that the r_h distribution closely resembles the inner Milky Way clusters, peaking at r_h~2.5 pc and with virtually no clusters more compact than r_h ~ 1 pc. The metal-poor clusters have on average an r_h 24% larger than the metal-rich ones. The cluster scale size shows a gradual and noticeable increase with galactocentric distance. Clusters are very slightly larger in the bluer waveband V a possible hint that we may be beginning to see the effects of mass segregation within the clusters. We also derived a color magnitude diagram for the M87 globular cluster system which show a striking bimodal distribution.
Keywords
Cite
@article{arxiv.0909.0272,
title = {Structural Parameters of the M87 Globular Clusters},
author = {Juan P. Madrid and William E. Harris and John P. Blakeslee and Matias Gomez},
journal= {arXiv preprint arXiv:0909.0272},
year = {2014}
}
Comments
ApJ accepted