PI: Sangeeta Malhotra, Arizona State U., email@example.com
Address: School of Earth and Space Exploration, PO Box 871404, Tempe, AZ 85287-1404 USA
CoI: Zhenya Zheng, Pontificia Universidad Catolica de Chile
CoI: James Rhoads, Arizona State U.
CoI: Junxian Wang, University of Science & Technology of China
CoI: Alistair Walker, CTIO
CoI: Leopoldo Infante, Pontificia Universidad Catolica de Chile
CoI: Linhua Jiang, Peking University
Title: Lyman Alpha Galaxies at z ~ 7 with DECam
Abstract: High redshift Ly$alpha$ emitting galaxies (LAEs) provide a powerful probe of the cosmic re-ionization. LAEs can be efficiently detected with deep narrowband imaging surveys. However, up to now only a handful of $z ga 7$ LAEs have been spectroscopically confirmed; whereas hundreds of LAEs have been identified at $z=6.5$. Does the redshift $z=7$ represent the epoch of reionization when lya photons from galaxies are severely scattered by the neutral IGM, or is the lack of $z > 7$ objects due to technical difficulties in finding them due to a decline in CCD sensitivities at 1 micron? DECam's large field of view and sensitivity at 1 micron would allow us to robustly address this question. We have built a custom narrowband filter for the Dark Energy Camera (DECam) centered at 9645 AA to take advantage of low sky background there. We request 3 nights of DECam time to search for $z$ $sim$ 7.0 LAEs in COSMOS. If there has been no evolution of LAEs since z=6.5, we expect to find 140 sources in this survey. If the IGM is neutral at $z=7$, we should see about 15-30 sources. Thus the numbers of LAEs would be a strong diagnostic of reionization at $z=7$. If reionization is inhomogenous or patchy at this redshift, the DECAM field would contain several hundred ionized bubbles of typical size, again allowing for robust statistics of inhomogenieties.
Program Type: Standard/Extragalactic
Run 1 (2016A): CT-4m/DECam -- 3n on Feb 04 - Feb 09 2016
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360