The extended structure of the remote cluster B514 in M31. Detection of extra-tidal stars

Abstract

We present a study of the density profile of the remote M31 globular cluster B514, obtained from HST/ACS observations. Coupling the analysis of the distribution of the integrated light with star counts we can reliably follow the profile of the cluster out to r~35", corresponding to ~130pc. The profile is well fitted, out to ~15 core radii, by a King Model having C=1.65. With an estimated core radius r_c=0.38", this corresponds to a tidal radius of r_t~17" (~65pc). We find that both the light and the star counts profiles show a departure from the best fit King model for r>~8" - as a surface brightness excess at large radii, and the star counts profile shows a clear break in correspondence of the estimated tidal radius. Both features are interpreted as the signature of the presence of extratidal stars around the cluster. We also show that B514 has a half-light radius significantly larger than ordinary globular clusters of the same luminosity. In the M_V vs. log r_h plane, B514 lies in a region inhabited by peculiar clusters, like Omega Cen, G1, NGC2419 and others, as well as by the nuclei of dwarf elliptical galaxies.

9 pages, 6 figures. Accepted for publication in Astronomy & Astrophysics

References in corpus (8)

• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy
• Structural parameters for globular clusters in M31 and generalizations for the fundamental plane
• An updated survey of globular clusters in M31. II Newly discovered bright and remote clusters
• ACS photometry of extended, luminous globular clusters in the outskirts of M31
• An updated survey of globular clusters in M 31. I. Classification and radial velocity for 76 candidate clusters
• ACS photometry of newly-discovered globular clusters in the outer halo of M31

Cited by in corpus (5)

• The nucleus of the Sagittarius dSph galaxy and M54: a window on the process of galaxy nucleation
• Another Non-segregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419
• The extended structure of the dwarf irregular galaxies Sextans A and Sextans B. Signatures of tidal distortion in the outskirts of the Local Group
• Globular Clusters and Dwarf Spheroidal Galaxies
• A near-ultraviolet view of the Inner Region of M31 with the Large Binocular Telescope