2000AJ....120.1668F

We report the detection of 1.3 mm continuum and near-infrared K-band (2.2 µm) emission from the submillimeter galaxy SMM J00266+1708. Although this galaxy is among the brightest submillimeter sources detected in the blank-sky surveys (L∼10¹³ L_☉), SMM J00266+1708 had no reliable optical or near-infrared counterpart. We used sensitive interferometric 1.3 mm observations with the Owens Valley Millimeter Array to determine the position of the submillimeter galaxy accurately. Follow-up near-infrared imaging with the Keck I telescope uncovered a new faint red galaxy at K=22.5 mag, which is spatially coincident with the 1.3 mm emission. This is currently the faintest confirmed counterpart of a submillimeter galaxy. Although the redshift of SMM J00266+1708 is still unknown, its high submillimeter/radio spectral index suggests that the system is at high redshift (z≳2). Approximately 50% or more of the submillimeter galaxies are faint red galaxies similar to SMM J00266+1708. These ultraluminous obscured galaxies account for a significant fraction of the total amount of star formation at high redshift despite being missed by optical surveys.