Newly Identified Star Clusters in M33. II. Radial HST/ACS Fields

Abstract

We present integrated photometry and color-magnitude diagrams for 161 star clusters in M33, of which 115 were previously uncataloged, using the Advanced Camera For Surveys Wide Field Channel onboard the Hubble Space Telescope. The integrated V-band magnitudes of these clusters range from Mv~-9 to as faint as Mv~-4, extending the depth of the existing M33 cluster catalogs by ~1 mag. Comparisons of theoretical isochrones to the color-magnitude diagrams using the Padova models yield ages for 148 of these star clusters. The ages range from Log (t)~7.0 to Log (t)~9.0. Our color-magnitude diagrams are not sensitive to clusters older than ~1 Gyr. We find that the variation of the clusters' integrated colors and absolute magnitudes with age is consistent with the predictions of simple stellar population models. These same models suggest that the masses of the clusters in our sample range from 5x10^3 to 5x10^4 *Msun.

28 pages, 12 figures, accepted for publication in The Astrophysical Journal

References in corpus (4)

• A Survey of Local Group Galaxies Currently Forming Stars. I. UBVRI Photometry of Stars in M31 and M33
• RR Lyrae Variables in M33. I. Evidence For a Field Halo Population
• A Catalog of Star Cluster Candidates in M33
• A Catalog of New M33 Star Clusters Based on the HST/WFPC2 Images

Cited by in corpus (15)

• Young massive star clusters
• GMC Evolutions in the Nearby Spiral Galaxy M33
• Photometric Properties of the M33 Star Cluster System
• The M33 Globular Cluster System with PAndAS Data: The Last Outer Halo Cluster?
• Deriving physical parameters of unresolved star clusters. I. Age, mass, and extinction degeneracies
• Star clusters in M33: updated UBVRI photometry, ages, metallicities, and masses
• The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). IV. Star Cluster Catalog
• Blending of Cepheids in M33
• Newly Identified Star Clusters in M33. III. Structural Parameters
• An HST/WFPC2 survey of bright young clusters in M31. IV. Ages and mass estimates
• An updated catalog of M33 clusters and candidates: $UBVRI$ photometry, and some statistical results
• Deriving physical parameters of unresolved star clusters IV. The M33 star cluster system
• New $ubvri$ photometry of 234 M33 star clusters
• Comparisons of Different Fitting Methods for the Physical Parameters of A Star Cluster Sample of M33 with Spectroscopy and Photometry
• Constraining star cluster disruption mechanisms