Spatially Resolved Spectroscopy of Starburst and Post-Starburst Galaxies in The Rich z~0.55 Cluster CL0016 16 - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We have used the Low Resolution Imaging Spectrograph LRIS on the W.M. KeckI telescope to obtain spatially resolved spectroscopy of a small sample of sixpost-starburst and three dusty-starburst galaxies in the rich cluster CL0016+16at z=0.55. We use this to measure radial profiles of the Hdelta and OII3727lines which are diagnostic probes of the mechanisms that give rise to theabrupt changes in star-formation rates in these galaxies. In the post-starburstsample we are unable to detect any radial gradients in the Hdelta lineequivalent width - although one galaxy exhibits a gradient from one side of thegalaxy to the other. The absence of Hdelta gradients in these galaxies isconsistent with their production via interaction with the intra-cluster medium,however, our limited spatial sampling prevents us from drawing robustconclusions. All members of the sample have early type morphologies, typical ofpost-starburst galaxies in general, but lack the high incidence of tidal tailsand disturbances seen in local field samples. This argues against a mergerorigin and adds weight to a scenario where truncation by the intra-clustermedium is at work. The post-starburst spectral signature is consistent over theradial extent probed with no evidence of OII3727 emission and strong Hdeltaabsorption at all radii i.e. the post-starburst classification is not anaperture effect. In contrast the dusty-starburst sample shows a tendency for acentral concentration of OII3727 emission. This is most straightforwardlyinterpreted as the consequence of a central starburst. However, otherpossibilities exist such as a non-uniform dust distribution which is expectedin such galaxies and-or a non-uniform starburst age distribution. The sampleexhibit late type and irregular morphologies.



Autor: Michael B. Pracy, Warrick J. Couch, Harald Kuntschner

Fuente: https://arxiv.org/







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