OLD HIGH-REDSHIFT GALAXIES AND PRIMORDIAL DENSITY FLUCTUATION SPECTRA

We have discovered a population of extremely red galaxies at z similar or equal to 1.5 which have apparent stellar ages of greater than or s imilar to 3 Gyr, based on detailed spectroscopy in the rest-frame ultr aviolet. In order for galaxies to have existed at the high collapse re dshifts indicated by these ages, there must be a minimum level of powe r in the density fluctuation spectrum on galaxy scales. This paper com pares the required power with that inferred from other high-redshift p opulations: damped Ly alpha absorbers and Lyman-limit galaxies at z si milar or equal to 3.2., If the collapse redshifts for the old red gala xies are in the range z(c) similar or equal to 6-8, there is general a greement between the various tracers on the required inhomogeneity on l-Mpc scales. This level of small-scale power requires the Lyman-limit galaxies to be approximately nu similar or equal to 3.0 fluctuations, implying a very large bias parameter b similar or equal to 6. If the collapse redshifts of the red galaxies are indeed in the range z(c) = 6-8 required for power spectrum consistency, their implied ages at z s imilar or equal to 1.5 are between 3 and 3.8 Gyr for essentially any m odel universe of current age 14 Gyr. The age of these objects as deduc ed from gravitational collapse thus provides independent support for t he ages estimated from their stellar populations. Such early-forming g alaxies are rare, and their contribution to the cosmological stellar d ensity is consistent with an extrapolation to higher redshifts of the star formation rate measured at z < 5; there is no evidence for a gene ral era of spheroid formation at extreme redshifts.