NGC 602: Ongoing Star Formation in a Young SMC Cluster
Lynn Redding Carlson (JHU), Antonella Nota (STScI/ESA), Elena Sabbi (STScI), Marco Sirianni (STScI/ESA), Joseph L. Hora (Harvard/CfA), Margaret Meixner (STScI), M. Clampin (NASA/Goddard), J. Gallagher (U. Wisconsin), M. S. Oey (U. Michigan), A. Pasquali (Inst. Of Astron., ETH), L. J. Smith (UCL), M. Tosi (Bologna Obs.), R. Walterbos (U. New Mexico)
(The following is a poster presentation made at the American
Astronomical Society conference in January 2007 in Seattle, Washington.)
The young stellar cluster NGC 602 is located in the wing of the SMC, Z~0.004, a low density region far from the main body of the galaxy with low gas and stellar content. From deep optical imaging with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST), we have discovered the existence of an extensive pre-Main Sequence (PMS) population, with stellar masses in the range 0.6–3 Mo. This pre-Main Sequence population formed coevally with the central cluster about 5 Myr ago. Spitzer Space Telescope (SST) images of the region in all four Infrared Array Camera (IRAC) bands reveal a second population of Young Stellar Objects (YSOs), which formed after the stars seen with HST/ACS imaging. Some of these very young objects are still embedded in nebular material. We infer that star formation started in this region ~5 Myr ago with the formation of the central cluster and gradually propagated towards the outskirts where we find evidence of on going star formation (~1 Myr).
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