Near-Infrared Colors of Submillimeter-selected Galaxies
Abstract
We report on deep near-infrared (NIR) observations of submillimeter-selected galaxies (SMGs) with the Near-Infrared Camera (NIRC) on the Keck I telescope. We have identified K-band candidate counterparts for 12 out of 15 sources in the SCUBA Cluster Lens Survey. Three SMGs remain nondetections with K-band limits of K>23 mag, corrected for lensing. Compensating for lensing, we find a median magnitude of K=22+/-1 mag for the SMG population, but the range of NIR flux densities spans more than a factor of 400. For SMGs with confirmed counterparts based on accurate positions from radio, CO, and/or millimeter continuum interferometric observations, the median NIR color is J-K=2.6+/-0.6 mag. The NIR-bright SMGs (K<19 mag) have colors of J-K~=2 mag, while the faint SMGs tend to be extremely red in the NIR (J-K>3 mag). We argue that a color selection criterion of J-K>~3 mag can be used to help identify counterparts of SMGs that are undetected at optical and radio wavelengths. The number density of sources with J-K>3 mag is 5 arcmin-2 at K<22.5 mag, greater than that of SMGs with S(850 μm)>2 mJy. It is not clear if the excess represents less luminous infrared-bright galaxies with S(850 μm)<~2 mJy, or if the faint extremely red NIR galaxies represent a different population of sources that could be spatially related to the SMGs.
- Publication:
-
The Astronomical Journal
- Pub Date:
- February 2004
- DOI:
- 10.1086/380943
- arXiv:
- arXiv:astro-ph/0310656
- Bibcode:
- 2004AJ....127..728F
- Keywords:
-
- Galaxies: Active;
- Galaxies: Evolution;
- Galaxies: Formation;
- Galaxies: Starburst;
- Astrophysics
- E-Print:
- Accepted, Astronomical Journal (scheduled for Feb04), 11 pages including 3 figures (fig1a, fig1b, fig2)