2014/05/22 by J. E. Ryon, A. Adamo, N. Bastian +6 · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.1088/0004-6256/148/2/33
31 pages, 9 figures, accepted to the AJ
arxiv created 2014/05/22 · arxiv updated 2015/06/19
We study the star cluster population of NGC 2997, a giant spiral galaxy located at 9.5 Mpc and targeted by the Snapshot Hubble U-band Cluster Survey (SHUCS). Combining our U-band imaging from SHUCS with archival BVI imaging from HST, we select a high confidence sample of clusters in the circumnuclear ring and disk through a combination of automatic detection procedures and visual inspection. The cluster luminosity functions in all four filters can be approximated by power-laws with indices of -1.7 to -2.3. Some deviations from pure power-law shape are observed, hinting at the presence of a high-mass truncation in the cluster mass function. However, upon inspection of the cluster mass function, we find it is consistent with a pure power-law of index -2.2±0.2 despite a slight bend at ∼2.5×104 M\odot. No statistically significant truncation is observed. From the cluster age distributions, we find a low rate of disruption (ζ∼-0.1) in both the disk and circumnuclear ring. Finally, we estimate the cluster formation efficiency (Γ) over the last 100 Myr in each region, finding 7±2% for the disk, 12±4% for the circumnuclear ring, and 10±3% for the entire UBVI footprint. This study highlights the need for wide-field UBVI coverage of galaxies to study cluster populations in detail, though a small sample of clusters can provide significant insight into the characteristics of the population.