NOAO >   Observing Info >   Approved Programs >   2015A-0187

Program Information for 2015A-0187

PI: Sean D Johnson, U. of Chicago, seanjohnson@uchicago.edu
Address: Department of Astronomy and Astrophysics, 5640 S. Ellis Ave, Chicago, IL 60637 U.S.A

CoI: Hsiao-Wen Chen, U. of Chicago
CoI: John S Mulchaey, Carnegie Observatories

Title: Deep optical photometry of galaxies in the field of 3C263

Abstract: A census of the observed baryons in the local Universe falls far short of the baryon density required by Big Bang Nucleosynthesis. Cosmological simulations suggest that a substantial portion of these missing baryons'' reside in a warm-hot, collisionally ionized intergalactic medium (WHIM). Quasar absorption lines from highly ionized species such as O\,VI constitute a sensitive available probe of this gas. A large number of O\,VI systems have now been identified using space-based ultraviolet (UV) spectrographs but ionization analysis of observed O\,VI systems suggest that a large fraction of O\,VI absorbers may result from photoionized gas rather than the WHIM. Results from our ongoing redshift surveys in the fields of UV-bright, southern quasar fields with the Magellan Telescopes confirm that the majority of O\,VI absorbers trace galaxy overdensities rather than the WHIM. To supplement the southern survey, we obtained galaxy redshifts in the field of 3C263 ($z_{\rm em} = 0.646$) using the GMOS spectrograph on Gemini North. The field-of-view limits the survey to galaxies within $\approx300$ kpc of the quasar sightline at $z=0.1$ which is insufficient for constraining the galaxy environment of O\,VI absorbers at this redshift. Here, we propose deep, multi-band optical imaging of the 3C263 field with the MOSAIC camera on the Mayall telescope to (1) enable targeting of galaxies for a future, wide galaxy redshift survey, (2) constrain the colors and stellar masses of galaxies in the field, and (3) place photometric redshift constraints on galaxies that fall below the magnitude limit of the galaxy redshift survey.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2015A):  KP-4m/MOSA -- 1n on Apr 13 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-0187