The Stellar Population of Stripped Cluster Spiral NGC 4522: A Local Analog to K+A Galaxies?

We present observations of the stripped Virgo Cluster spiral NGC 4522, aclear, nearby example of a galaxy currently undergoing ISM-ICM stripping.Utilizing SparsePak integral field spectroscopy on the WIYN 3.5m telescope andGALEX UV photometry, we present an analysis of the outer disk (r > 3 kpc)stellar population of this galaxy, beyond the HI and Halpha truncation radius.We find that the star formation in the gas-stripped outer disk ceased veryrecently, ~100 Myr ago, in agreement with previous claims that this galaxy iscurrently being stripped. At the time of this stripping, data and modelssuggest that the galaxy experienced a modest starburst. The stripping isoccurring in a region of the cluster well outside the cluster core, likelybecause this galaxy is experiencing extreme conditions from a dynamic ICM dueto an ongoing sub-cluster merger. The outer disk has a spectrum of a K+Agalaxy, traditionally observed in high-redshift cluster galaxies. In the caseof NGC 4522, a K+A spectrum is formed by simple stripping of the interstellargas by the hot intracluster medium. These data show K+A spectra can be createdby cluster processes and that these processes likely extend beyond the clustercore.Comment: 5 pages, 3 figures, accepted for publication in ApJ Letter