Carnegie-Spitzer-IMACS Survey: Following the End of Star Formation in Massive Galaxies Since z=1
Abstract
The Carnegie-Spitzer-IMACS (CSI) Survey, currently underway at Magellan and NOAO, couples low-resolution optical spectroscopy with broadband near- and mid-IR photometry to obtain redshifts, masses, and emission line fluxes massive galaxies out to z 1.4. When complete, CSI will include over 105 3.6 micron-selected galaxies over 15 deg2 in 3 extragalactic fields, providing an unprecedented mass-selected galaxy sample over a volume comparable to SDSS. Since targets are selected in the rest-frame near-IR, CSI is highly complete to relatively low masses for both blue and red galaxies, making it ideally suited for studies of the mass buildup in galaxies, the shutdown of star formation, and the rise of galaxy groups over the past 10 Gyr.
Here we present initial results on the quiescent fraction of massive galaxies since z 1. By using empirically- and theoretically-motivated UVJ rest-frame color selection, we reliably separate star-forming from non-star-forming galaxies. In particular, we focus on the dependence of star-forming fraction on environment, tracing its evolution in both groups and the low-density field, in order to determine the importance of the group environment on the decline of cosmic star formation from z=1-0.- Publication:
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American Astronomical Society Meeting Abstracts #219
- Pub Date:
- January 2012
- Bibcode:
- 2012AAS...21922903K