The NEWFIRM Medium-band Survey: Photometric Catalogs, Redshifts and the
  Bimodal Color Distribution of Galaxies out to z~3
  We present deep near-infrared (NIR) medium-bandwidth photometry over the
wavelength range 1-1.8 microns in the All-wavelength Extended Groth strip
International Survey (AEGIS) and Cosmic Evolution Survey (COSMOS) fields. The
observations were carried out as part of the NEWFIRM Medium-Band Survey (NMBS),
an NOAO survey program on the Mayall 4m telescope on Kitt Peak using the NOAO
Extremely Wide-Field Infrared Imager (NEWFIRM). In this paper, we describe the
full details of the observations, data reduction and photometry for the survey.
We also present a public K-selected photometric catalog, along with accurate
photometric redshifts. The redshifts are computed with 37 (20) filters in the
COSMOS (AEGIS) fields, combining the NIR medium-bandwidth data with existing
ultraviolet (UV; Galaxy Evolution Explorer), visible and NIR
(Canada-France-Hawaii Telescope and Subaru) and mid-IR (Spitzer/IRAC) imaging.
We find excellent agreement with publicly available spectroscopic redshifts,
with sigma_z/(1+z)~1-2% for ~4000 galaxies at z=0-3. The NMBS catalogs contain
~13,000 galaxies at z>1.5 with accurate photometric redshifts and rest-frame
colors. Due to the increased spectral resolution obtained with the five NIR
medium-band filters, the median 68% confidence intervals of the photometric
redshifts of both quiescent and star-forming galaxies are a factor of ~2 times
smaller when comparing catalogs with medium-band NIR photometry to NIR
broadband photometry. We show evidence for a clear bimodal color distribution
between quiescent and star-forming galaxies that persists to z~3, a higher
redshift than has been probed so far.
