Hubble Space Telescope Photometry of Globular Clusters in M81

Abstract

We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with mV \leq 23 mag identified in Hubble Space Telescope Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically-confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3σ color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V ~(20.26 \pm 0.13) mag, corresponding to a distance of ~3.7\pm0.3 Mpc. The blue and red GC candidates, and the metal-rich (MR) and metal-poor (MP) spectroscopically confirmed clusters, are similar in half-light radius, respectively. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and "good" candidates shows an increase in half-light radius as a function of galactocentric distance.

42 figures, 14 pages, accepted to AJ

References in corpus (9)

• HST/ACS Wide-Field Photometry of the Sombrero Galaxy Globular Cluster System
• Globular Cluster Systems in Giant Ellipticals: the Mass/Metallicity Relation
• The M31 globular cluster system: ugriz and K-band photometry and structural parameters
• The ACS Fornax Cluster Survey VII. Half-Light Radii of Globular Clusters in Early-Type Galaxies
• Diamonds on the Hat: Globular Clusters in The Sombrero Galaxy (M104)
• Sizes of Confirmed Globular Clusters in NGC 5128: A Wide-Field High-Resolution Study
• Structural Parameters of the M87 Globular Clusters
• Spectroscopy of M81 Globular Clusters
• Star Cluster Candidates in M81

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• The SLUGGS Survey: HST/ACS Mosaic Imaging of the NGC 3115 Globular Cluster System
• Discovery of the most isolated globular cluster in the local universe
• Ultra-Compact Dwarfs around NGC 3268
• A Very Large Array Search for Intermediate-Mass Black Holes in Globular Clusters in M81
• A Search for Intergalactic Globular Clusters in the Local Group
• J-PLUS: A catalogue of globular cluster candidates around the M81/M82/NGC3077 triplet of galaxies
• A New Metal-poor Globular Cluster and Resolved Stars in the Outer Disk of the Black Eye Galaxy M64: Implication for the Origin of the Type III Disk Break
• Calibrating X-ray binary luminosity functions via optical reconnaissance II. The high-mass XLF and globular cluster population of X-ray binaries in the low star-forming spiral M81
• New Globular Cluster Candidates in the M81 group
• Ages and structural and dynamical parameters of two globular clusters in the M81 group
• The Ancient Globular Clusters of NGC 1291