NOAO >   Observing Info >   Approved Programs >   2015A-0168

# Program Information for 2015A-0168

PI: Kyoung-Soo Lee, Purdue U., soolee@purdue.edu
Address: Physics Department, 525 Northwestern Avenue, West Lafayette, Indiana 47907 United States

CoI: Arjun Dey, NOAO
CoI: Anthony H Gonzalez, U. of Florida
CoI: Ke Shi, Purdue U.
CoI: Buell T Jannuzi, U. of Arizona
CoI: Hanae Inami, NOAO
CoI: Naveen A Reddy, UC Riverside
CoI: Samuel Frampton, Purdue U.

Title: Witnessing the Earliest Stage of Cluster Formation at Z=3.78

Abstract: The formation and evolution of galaxies is known to be affected by the local environment in which they reside. While observational evidence of the environmental effects on the evolution of galaxies are abundantly found at low redshift, the detailed star formation and assembly histories, and quenching times of typical cluster galaxies, and how these differ from those in the field are not well understood. The best way to investigate galaxy formation in different environments is to witness it directly at the formation epoch of cluster galaxies, i.e., $z\gtrsim3$. We have discovered a very large overdensity ($\sim 10\times$ the mean galaxy density) at $z=3.78$, surrounded by converging filaments and voids. By $z=0$, this `protocluster' will evolve to a Coma-like cluster with $\sim2\times10^{15}M_\odot$. Taking advantage of the unparalleled wide-field imaging capability of the NEWFIRM, we propose to take deep $JHK_S$ imaging centered on the protocluster. We will 1) measure the stellar masses and ages for a large sample of spectroscopically confirmed galaxies in the protocluster and in the field; 2) determine probabilistic cluster membership of galaxies (by improving photo-z estimate); 3) compare the stellar population properties of galaxies in different environments; 4) uncover massive red population (dusty starbursts or quenched galaxies) that may be associated with the region.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2015A):  KP-4m/NEWFIRM -- 6n on Mar 27 - Apr 01 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 >   2015A-0168