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Near ultraviolet-infrared colours of red-sequence galaxies in local clusters
We present GALEX near-ultraviolet (NUV) and Two-Micron All-Sky SurveyJ-band photometry for red-sequence galaxies in local clusters. We definequiescent samples according to a strict emission threshold, removinggalaxies with very recent star formation. We analyse the NUV-Jcolour-magnitude relation (CMR) and find that the intrinsic scatter isan order of magnitude larger than for the analogous optical CMR (~0.35rather than 0.05 mag), in agreement with previous studies. Comparing theNUV-J colours with spectroscopically derived stellar populationparameters, we find a strong (>5.5σ) correlation withmetallicity, only a marginal trend with age, and no correlation with theα/Fe ratio. We explore the origin of the large scatter andconclude that neither aperture effects nor the UV upturn phenomenoncontribute significantly. We show that the scatter could be attributedto simple `frosting' by either a young or a low-metallicitysubpopulation.
| H-Band and Spectroscopic Properties of A1644
We discuss H-band (1.65 μm) near-infrared photometry of the central 9h-2 Mpc2 of Abell 1644 (A1644) to a limitingMH~M*H+3 (throughout this paper H0=100h km s-1 Mpc-1). There are 861 galaxies in thephotometric survey region. We also measured radial velocities of 155galaxies; 141 of these are cluster members within 2.44 h-1Mpc of the cluster center. The completeness limit of the spectroscopicsurvey is H~13 (MH~M*H). The clustervelocity dispersion of σ~1000 km s-1 remains constantout to the limiting radius. We find no evidence for substructure in thecluster. The cluster mass within R=2.4 h-1 Mpc is7.6+/-1.3×1014 h -1 Msolar. Wecompute the cluster luminosity function; the Schechter parametersα=-1.14+/-0.08 and M*H=-24.3+/-0.2 (withh=0.5) agree well with other H-band luminosity functions. From thevirial theorem and the caustic method we compute one of the firstmass-to-light ratios at H; the result is M/LH=82-127 hMsolar/Lsolar within 1.5 h-1 Mpc. Thisratio corresponds to 374-579 h Msolar/Lsolar at R.The agreement of our IR measurement with previous M/L determinationsindicates that at low redshift dust and young stellar populations mayproduce only negligible systematic errors in optical mass-to-lightratios.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| A catalog of 1268 radial velocities in 15 rich clusters
Abstract image available at:http://adsabs.harvard.edu/abs/1988AJ.....95..284D
| A catalog of morphological types in 55 rich clusters of galaxies
Data are presented from a study of 55 rich clusters of galaxies. Thedata include positions, morphological types, estimated total magnitudes,bulge sizes, and ellipticities for about 6000 galaxies, as determinedfrom high scale photographic plates. Data reduction procedures aredescribed, and a brief analysis of cluster richness, which indicatesthat Abell richness classes are only rough indicators of total clustermembership, is included.
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