NOAO >   Observing Info >   Approved Programs >   2016A-0386

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Program Information for 2016A-0386


PI: Sangeeta Malhotra, Arizona State U., sangeeta.malhotra@asu.edu
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

Scheduled Nights:
Run 1 (2016A):  CT-4m/DECam -- 3n on Feb 04 - Feb 09 2016


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