Related papers: Colour-magnitude relations and spectral line stren…

We have observed three fields of the Coma cluster of galaxies with a narrow band (modified Stromgren) filter system. Observed galaxies include 31 in the vicinity of NGC 4889, 48 near NGC 4874, and 60 near NGC 4839 complete to M_5500=-18 in…

We explore the origin of the colour-magnitude relation (CMR) of early type galaxies in the Virgo cluster using spectra of very high S/N ratio for six elliptical galaxies selected along the CMR. The data are analysed using a new evolutionary…

Using new narrowband color observations of early-type galaxies in clusters, we reconstruct the color-magnitude relation (CMR) with a higher degree of accuracy than previous work. We then use the spectroscopically determined ages and…

(abr.) We present the analysis of the spectroscopic catalog of galaxies in the Coma cluster from Mobasher et al. This catalog comprises ~300 spectra of cluster members with magnitudes M_B=-20.5 to -14 in two areas of ~1 X 1.5 Mpc towards…

We analyse the stellar populations of 75 red-sequence dwarf galaxies in the Coma cluster, based on high signal-to-noise spectroscopy from the 6.5m MMT. The sample covers a luminosity range 3-4 magnitudes below M*, in the cluster core and in…

We investigate the origin of the colour-magnitude relation (CMR) followed by early-type cluster galaxies by using a combination of cosmological N-body simulations of cluster of galaxies and a semi-analytic model of galaxy formation (Lagos,…

We present a new photometric catalogue of the Coma galaxy cluster in the Johnson U- and V- bands. We cover an area of 3360arcmin2 of sky, to a depth of V=20 mag in a 13 arcsec diameter aperture, and produce magnitudes for ~1400 extended…

We present age and metallicities determinations based on narrow band continuum colors for the galaxies in the rich clusters A1185 and Coma. Using a new technique to extract luminosity-weighted age and [Fe/H] values for non-star-forming…

We investigate the origin of the colour-magnitude relation (CMR) observed in cluster galaxies by using a combination of a cosmological N-body simulation of a cluster of galaxies and a semi-analytic model of galaxy formation. The departure…

We use 16 micron, Spitzer-IRS, blue peakup photometry of 50 early-type galaxies in the Coma cluster to define the mid-infrared colour-magnitude relation. We compare with recent simple stellar population models that include the mid-infrared…

We investigate the origin of the color-magnitude relation (CMR) observed in cluster galaxies by using a combination of cosmological N-body/SPH simulations of galaxy clusters, and a semi-analaytic model of galaxy formation (Lagos, Cora &…

We present line-strength gradients for 22 spectral indices measured in a sample of 82 early-type galaxies in different environments,including the high-density core of the Coma cluster, the Virgo cluster,poor groups,and field galaxies. We…

We analyse luminosity-weighted ages and metallicity (Z) of galaxies in a continuous range of environments, i.e. clusters, filaments and voids prevalent in the Coma supercluster ($\sim 100 h^{-1}$ Mpc). Specifically, we employ two absorption…

We use a large sample of galaxies drawn from the Sloan Digital Sky Survey (SDSS) and Two Micro All Sky Survey (2MASS) to present Color-Magnitude Relations (CMRs) for late-type galaxies in both optical and optical-infrared bands. A sample…

We present an unbiased method for evaluating the ranges of ages and metallicities which are allowed by the photometric properties of the stellar populations that dominate the light of early-type galaxies in clusters. The method is based on…

We derive central values and logarithmic gradients for the Hbeta, Mg and Fe indices of 35 early-type galaxies in the Coma cluster. We find that pure elliptical galaxies have on average slightly higher velocity dispersions, lower Hbeta, and…

The color-magnitude relation (CMR) of early-type galaxies in clusters provides a powerful tool for finding clusters and determining photometric redshifts for clusters using two-filter imaging data. We demonstrate the high accuracy of…

The traditional use of fixed apertures in determining the well known color-magnitude (CM) relation of early type galaxies, coupled with the presence of radial color gradients within these systems, introduces a bias in the CM relation…

We investigate the development of the colour-magnitude re- lation (CMR) of cluster galaxies. This study is carried out using a semi- analytic model of galaxy formation and evolution coupled to a sample of simulated galaxy clusters of…

We revisit the color-magnitude relation (CMR) of the Virgo cluster early-type galaxies in order to explore its alleged non-linearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster…