NGC 2146: a Nearby Laboratory for Cluster Formation Modes

Type Conference Paper
Names Angela Adamo, J. S. Gallagher, L. Smith, M. Westmoquette, I. S. Konstantopoulos, N. Bastian, J. E. Ryon, E. Zackrisson, S. S. Larsen, J. Charlton, D. Weisz
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #219, #438.03
Volume 219
Date January 1, 2012
Short Title NGC 2146
Library Catalog NASA ADS
Abstract As part of the Snapshot Hubble U-band Cluster Survey (SHUCS), we present the first complete study of the star cluster population in NGC 2146. NGC 2146 is a spectacular nearby starburst galaxy, which has experienced a recent merger event. The high-resolution cameras onboard the Hubble Space Telescope have produced a superb imaging dataset for this galaxy. The tidal streams and some starburst regions in the edge-on disk are already visible in the ultra-violet and B bands. However, only the longer wavelengths, such as R, I, and the near-infrared bands, can penetrate the dust screen and reveal the complexity of the starburst operating in the central regions. Several hundreds of star clusters have been detected. We have performed a detailed analysis of the spectral energy distributions of the clusters to constrain age, mass, and extinction of the entire population. These properties are used to map the starburst propagation in the galaxy and to understand how diverse galactic environments affect cluster formation. The most massive clusters are observed in the central starburst region, likely produced by the gas compression during the merging phase. In the tidal stream, where the extinction is low, star and cluster formation has happened in a less dense environment. The presence of numerous HII regions and clusters with ages of a few tens of Myr proves that star formation in the tidal stream has recently taken place. Several cluster complexes have been found in the disk, with age spreads not larger than 10 Myr. The cluster complexes in the disk differ from those in the stream in that they are more compact and probably formed in a single starburst episode. Finally, we observe several globular clusters located in the galactic halo. Research based on observations obtained with the NASA/ESA Hubble Space Telescope through program IDs 12229 and 12206.
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