The K-Band Luminosity Function in Galaxy Clusters to z

Space Telescope Science Institute, Baltimore, Maryland, United States
The Astronomical Journal (Impact Factor: 4.02). 12/2007; 118(2):719. DOI: 10.1086/300978
Source: arXiv


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; 598(1). DOI:10.1023/A:1024661826229 · 5.99 Impact Factor
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    ABSTRACT: We compare the luminosity functions for red galaxies lying on the restframe (U-V) color-magnitude sequence in a homogeneous sample of ten X-ray luminous clusters from the MACS survey at z~0.5 to a similarly selected X-ray cluster sample at z~0.1. We exploit deep Hubble Space Telescope ACS imaging in the F555W and F814W passbands of the central 1.2Mpc diameter regions of the distant clusters to measure precise colors for the galaxies in these regions and statistically correct for contamination by field galaxies using observations of blank fields. We apply an identical analysis to ground-based photometry of the z~0.1 sample. This comparison demonstrates that the number of faint, Mv~ -19, red galaxies relative to the bright population seen in the central regions of massive clusters has roughly doubled over the 4 Gyrs between z~0.5 and z~0.1. We quantify this difference by measuring the dwarf to giant ratio on the red sequence which increases by a factor of at least 2.2+/- 0.4 since z~0.5. This is consistent with the idea that many faint, blue star-forming galaxies in high density environments are transforming onto the red sequence in the last half of the Hubble time.
    The Astrophysical Journal 04/2007; 661(1). DOI:10.1086/514329 · 5.99 Impact Factor
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    ABSTRACT: Using K- band imaging for 15 of the Canadian Network for Observational Cosmology ( CNOC1) clusters we examine the near- infrared properties of moderate- redshift ( 0.19 < z < 0.55) galaxy clusters. We find that the number of K- band selected cluster galaxies within R-500 ( the halo occupation number, HON) is well correlated with the cluster dynamical mass ( M-500) and X- ray temperature ( T-X); however, the intrinsic scatter in these scaling relations is 37% and 46%, respectively. Comparison with clusters in the local universe shows that the HON-M-500 relation does not evolve significantly between z = 0 and z similar to 0.3. This suggests that if dark matter halos are disrupted or undergo significant tidal stripping in high-density regions as seen in numerical simulations, the stellar mass within the halos is tightly bound, and not removed during the process. The total K- band cluster light ( L-200,L-K) and K-band-selected richness ( parameterized by B-gc,B- K) are also correlated with both the cluster T-X and M-200. The total ( intrinsic) scatter in the L-200,L-K-M-200 and B-gc,B-K- M-200 relations are 43% (31%) and 35% (18%), respectively, and indicates that for massive clusters both L-200,L-K and B-gc,B-K can predict M-200 with accuracy similar to that of T-X, L-X, or optical richness ( B-gc). Examination of the mass-to-light ratios of the clusters shows that similarly to local clusters, the K- band mass-to-light ratio is an increasing function of halo mass. Using the K-band mass-to-light ratios of the clusters, we apply the Oort technique and find Omega(m,0) = 0.22 +/- 0.02, which agrees well with recent combined concordance cosmology parameters, but, similarly to previous cluster studies, is on the low- density end of preferred values.
    The Astrophysical Journal 07/2007; 663(1):150-163. DOI:10.1086/518229 · 5.99 Impact Factor
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