Back to Volume
Paper: Superior Photometric Redshifts with Dusty Star Cluster Spectral Energy Distributions
Volume: 381, The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution
Page: 285
Authors: Hunt, L.K.; Maiolino, R.
Abstract: The photometric redshift technique is fundamental in estimating redshifts for samples of very (optically) faint galaxies at z≥1. However, the accuracy of this estimate depends strongly on the ability of the spectral energy distribution (SED) template to fit the observed redshifted SED.We demonstrate here that the SEDs of massive stellar clusters enshrouded in dust fit the observed SEDs of high-redshift samples better than the more usual templates of M82 and Arp220. This is true because of the steep rise in the rest-frame optical, the lack of significant PAH features, the broad infrared peak, and the flat (thermal dominated) radio emission in the cluster SED templates. We apply these templates to several samples of high-redshift galaxies with new Spitzer photometry, and show that: (1) the photometric and spectroscopic redshifts derived from training sets agree to within 0.1−0.3; (2) the extinguished cluster templates are inevitably the best fits to the observed SEDs for the majority of objects. Finally, we point out the similarities of the new SED templates and AGN, and suggest that a substantial fraction of putative AGN detected by Spitzer are in fact highly extinguished massive star clusters.
Back to Volume