Article

The K-Band Luminosity Function in Galaxy Clusters to z

The Astronomical Journal (Impact Factor: 4.97). 12/2007; 118(2):719. DOI: 10.1086/300978
Source: arXiv

ABSTRACT We present K-band luminosity functions for galaxies in a heterogeneous sample of 38 clusters at 0.1 < z < 1. Using infrared-selected galaxy samples, which generally reach 2 mag fainter than the characteristic galaxy luminosity L*, we fitted Schechter functions to background-corrected cluster galaxy counts to determine K* as a function of redshift. Because of the magnitude limit of our data, the faint-end slope α is fixed at -0.9 in the fitting process. We find that K*(z) departs from no-evolution predictions at z > 0.4 and is consistent with the behavior of a simple, passive luminosity evolution model in whichgalaxies form all their stars in a single burst at zf = 2(3) in an H0 = 65 km s-1 Mpc-1, ΩM = 0.3, ΩΛ = 0.7(0) universe. This differs from the flat or negative infrared luminosity evolution, which has been reported for high-redshift field galaxy samples. We find that the observed evolution appears to be insensitive to cluster X-ray luminosity or optical richness, implying little variation in the evolutionary history of galaxies over the range of environmental densities spanned by our cluster sample. These results support and extend previous analyses based on the color evolution of high-redshift cluster E/S0 galaxies, indicating not only that their stellar populations formed at high-redshift, but that the assembly of the galaxies themselves was largely complete by z ≈ 1 and that subsequent evolution down to the present epoch was primarily passive.

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    ABSTRACT: [abridged] We investigate the Butcher-Oemler effect in a sample of K-selected galaxies in 33 clusters at 0.15 < z < 0.92. We attempt to duplicate the original Butcher-Oemler analysis as closely as possible given the characteristics of our data. We find that the infrared selected blue fractions are lower than those measured in the optical and that the trend with redshift is much weaker. Comparison with optical data in clusters in common with Butcher & Oemler (1984) shows that infrared selection is the primary difference between our study and optically selected samples. We suggest that the Butcher-Oemler effect is in large part due to a population of star-forming low mass galaxies which will evolve into dwarf galaxies. These early results point to the need for larger and deeper infrared samples of cluster galaxies to address this issue Comment: 37 pages, 19 figures, ApJ accepted (vol 598 n1)
    The Astrophysical Journal 07/2003; · 6.73 Impact Factor

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