NOAO >   Observing Info >   Approved Programs >   2013A-0321

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Proposal Information for 2013A-0321


PI: Alessandro Sonnenfeld, UC Santa Barbara, sonnen@physics.ucsb.edu
Address: Department of Physics, Broida Hall, Building 572, Santa Barbara, CA, 93106-9530, USA

CoI: Tommaso Treu, UC Santa Barbara
CoI: Sherry Suyu, UC Santa Barbara
CoI: Raphael Gavazzi, Institut Astrophysique de Paris
CoI: Phil Marshall, University of Oxford

Title: The mass assembly of early-type galaxies with SL2S

Abstract: How do massive early-type galaxies form? Merging is thought to be a key process, but the details are not clear: the important merger events could be minor or major, wet or dry. A key test for any theory of massive galaxy evolution is to explain the observed total density profiles of early-type galaxies, which can be precisely measured by joint analysis of strong gravitational lensing and stellar kinematics data. We are constructing a sample of 35 lenses at redshift 0.4--0.7, detected in the CFHTLS imaging survey, to investigate our tentative detection of an average steepening of the density profiles with cosmic time. To model each galaxy's profile slope accurately we need an accurate measurement of the lensed source redshift, which for some systems is best made in the NIR wavebands. With its broad wavelength coverage, GNIRS is very well-suited to this work: we propose to measure 5 source redshifts in this way in semester 2013A, to complete our observational campaign.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2013A-0321

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