Deep IRAC imaging of a complete sample of SPT-selected clusters at z~1.5: the restframe-NIR view of galaxies in the most massive very distant structures
Abstract
We propose deep IRAC mapping at 3.6um and 4.5um of a complete sample of the five most distant clusters discovered in the SPT-SZ survey, to get a detailed (at least M*+3) restframe NIR (thus stellar mass) picture of galaxy populations in the densest environments at z~1.5. This redshift is a crucial transition time for massive galaxies in cluster environments, bridging the major star formation events at z~2 that built most of the stars in massive cluster early-types, and the z~1 regime that is largely characterized by passive evolution in cluster cores. All five targeted clusters have scheduled HST observations in the ACS/F814W and WFC3/F140W bands probing stellar populations and morphologies. The observations proposed here will crucially complement these data, probing the restframe NIR luminosity function (and galaxy stellar mass function), the galaxy number density and stellar mass profiles, stellar mass fractions and halo occupation distribution. The depth of these observations and the clear selection function of the cluster sample will be critical in addressing the still controversial results of the first very few studies of stellar mass assembly in early cluster environments. A real synergy of HST and Spitzer observations, in combination with a unique cluster sample, will allow an important step forward in our understanding of crucial aspects of galaxy evolution in the first massive clusters.
- Publication:
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Spitzer Proposal
- Pub Date:
- October 2015
- Bibcode:
- 2015sptz.prop12030S