Photometric properties of the Arp 220 super star clusters |
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| Authors: | Yasuhiro Shioya Yoshiaki Taniguchi Neil Trentham |
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| Institution: | Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan;Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA |
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| Abstract: | We investigate the photometric properties of six super stellar clusters (SSCs) seen in both the optical and near-infrared Hubble Space Telescope images of the local ultraluminous starburst galaxy Arp 220. Three of the SSCs are located in the central 0.5-kpc region. The remaining three are in the circumnuclear region between 0.5 and 2.5 kpc from the centre. Comparing the observed spectral energy distributions (SEDs) of the SSCs with the Starburst99 models of Leitherer et al., we confirm that all three nuclear SSCs are heavily obscured  Considering the results from this comparison in conjunction with measurements of the near-infrared CO absorption index and of millimetre CO linewidths and luminosities, we estimate the ages of the nuclear SSCs to be 107–108 yr. The bolometric luminosity of the three nuclear SSCs is at most one-fifth of the total bolometric luminosity of Arp 220. On the other hand, the circumnuclear SSCs have little internal extinction  These contribute negligibly to the total bolometric luminosity. |
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| Keywords: | stars: formation galaxies: individual: Arp 220 galaxies: starburst galaxies: star clusters |
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