NOAO >   Observing Info >   Approved Programs >   2014A-0427

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Proposal Information for 2014A-0427


PI: Keren Sharon, University of Michigan, kerens@umich.edu
Address: Department of Astronomy, 830 Dennison, 501 East University Avenue, Ann Arbor, MI, 48109-1090, USA

CoI: Michael Gladders, University of Chicago
CoI: Traci Johnson, University of Michigan
CoI: Matthew Bayliss, Harvard University
CoI: Jane Rigby, NASA Goddard Space Flight Center

Title: “Resolving the Star Formation in Distant Galaxies” – supporting ground-based spectroscopy for a large HST program

Abstract: Our collaboration is conducting a large, 107 orbits, HST program to image 37 fields of strong-lensing clusters. The goal of the HST program is to answer two questions: What was the morphology of star formation in galaxies at the epoch when most stars formed? What were the fundamental size scales of that star formation? We will be able to answer these questions, for the first time, thanks to the unique combination of HST’s exquisite image quality and the magnification boost of strong lensing that will overcome the normal diffraction limit of HST. A critical step for the interpretation of the observations, is computing accurate lens models; all the intrinsic properties of the background galaxies depend on their magnification by lensing. The lens modeling effort will be led by PI Sharon, and conducted at the University of Michigan. Here we propose to support the HST program with ground-based spectroscopy of background sources. The robustness of lens models strongly relies on correct identification of multiply-lensed galaxies, and an accurate measurement of their redshift. The proposed observations will allow us to more than double the number of lensed galaxies with spectroscopic redshift in each cluster, thus enabling their use as constraints in the lens modeling process. We will target new arc candidates that have been discovered in the HST data.


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 >   2014A-0427

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