NOAO >   Observing Info >   Approved Programs >   2015B-0229

Program Information for 2015B-0229

PI: Zheng Cai, U. of Arizona, zcai@ucolick.org
Address: Physics Department, 1118E, 4th Street, Tucson, AZ 85721 USA

CoI: Xiaohui Fan, U. of Arizona
CoI: Arjun Dey, NOAO
CoI: Brenda Frye, U. of Arizona
CoI: Ann Zabludoff, U. of Arizona
CoI: Richard F Green, U. of Arizona
CoI: Yun-Hsin Huang, U. of Arizona

Title: Mapping the Most Massive Overdensity Through HI: KPNO/MOSAIC Observations of Galaxy Overdensities at z=2.3

Abstract: By examining the absorption spectra of $\sim$140,000 quasar sight- lines over a volume of 1 Gpc$^3$ in the SDSS-III, we have identified the most extreme overdensities of Ly$\alpha$ absorbers at $z=2.32\pm0.04$, which then can be probed in Ly$\alpha$ emission with our custom narrowband filter. These overdensities, which could be further suggested by a high concentration of quasars at the same redshift, are likely to represent the most biased regions in the Universe at the peak of galaxy formation ($z=2-3$). Our simulations and early observations support a strong correlation between the high optical depth Ly$\alpha$ absorbers, which arise from the IGM, and true 3-D mass overdensities over scales of $10-30$ $h^{-1}$ Mpc. We now have discovered three of the highest absorber overdensities at $z\sim2$ and within 20 $h^{-1}$ Mpc found to date. With KPNO-4m/MOSAIC, we propose to carry out deep narrowband (NB403) + broadband (Bw) imaging to find Ly$\alpha$ emitting galaxies in these systems. These observations will build a crucial sample of large-scale structures traced by extreme Ly$\alpha$ absorber overdensities, and reveal the Ly$\alpha$- and UV-based star formation activity in these rare galaxy environments.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2015B):  KP-4m/MOSA -- 3n on Oct 12 - Oct 14 2015

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 >   2015B-0229