Barred Galaxies in the Abell 901-2 Supercluster with STAGES - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado

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Abstract: We present a study of bar and host disk evolution in a dense clusterenvironment, based on a sample of ~800 bright MV <= -18 galaxies in the Abell901-2 supercluster at z~0.165. We use HST ACS F606W imaging from the STAGESsurvey, and data from Spitzer, XMM-Newton, and COMBO-17. We identify andcharacterize bars through ellipse-fitting, and other morphological featuresthrough visual classification. 1 We explore three commonly used methods forselecting disk galaxies. We find 625, 485, and 353 disk galaxies, respectively,via visual classification, a single component S-ersic cut n <= 2.5, and ablue-cloud cut. In cluster environments, the latter two methods miss 31% and51%, respectively, of visually-identified disks. 2 For moderately inclineddisks, the three methods of disk selection yield a similar global optical barfraction f bar-opt of 34% +10%-3%, 31% +10%-3%, and 30% +10%-3%,respectively. 3 f bar-opt rises in brighter galaxies and those which appearto have no significant bulge component. Within a given absolute magnitude bin,f bar-opt is higher in visually-selected disk galaxies that have no bulge asopposed to those with bulges. For a given morphological class, f bar-opt risesat higher luminosities. 4 For bright early-types, as well as faint late-typesystems with no evident bulge, the optical bar fraction in the Abell 901-2clusters is comparable within a factor of 1.1 to 1.4 to that of field galaxiesat lower redshifts 5 Between the core and the virial radius of the cluster atintermediate environmental densities, the optical bar fraction does not appearto depend strongly on the local environment density and varies at most by afactor of ~1.3. We discuss the implications of our results for the evolution ofbars and disks in dense environments.

Autor: I. Marinova UT Austin, S. Jogee UT Austin, A. Heiderman UT Austin, F. D. Barazza EPFL, M. E. Gray Nottingham, M. Barden Innsbruck


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