2000ApJ...539..570G

Deep infrared and optical surveys have recently revealed a large number of very red (R-K>6) galaxies, labeled extremely red objects (EROs). Many have been identified with broadband photometry, but very few have been observed spectroscopically. From the limited spectra available, it appears that they may form a heterogeneous population. There are EROs at high redshifts with dusty, active star formation (studied by Dey and coworkers) as well as EROs with old stellar populations and little dust (studied by Soifer and coworkers). In order to further the study of these galaxies, we have taken near-infrared spectra with the Keck Telescope of three EROs found in the fields of high-redshift active galactic nuclei. The continuum is well detected in each, but no emission lines or spectral breaks are detected. We have found probable redshifts, extinctions, ages, and star formation histories for each of these EROs based on fitting their spectral energy distributions. For every age and star formation model, the fits are constrained in redshift and reddening to small regions. Due to the unknown nature of these objects, we cannot rule out values of A_v as high as 15 at low redshifts. None of the EROs have spectra consistent with the redshifts of their nearby high-redshift objects.