Post-Starburst Galaxies in the Coma, DC2048--52, and DC0326--53 clusters

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Session 106 -- Galaxies: Photometry and Spectrophotometry
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

[106.04] Post-Starburst Galaxies in the Coma, DC2048--52, and DC0326--53 clusters

Nelson Caldwell (SAO), Jim Rose (UNC)

We present new multi-fiber spectroscopy of galaxies in three nearby clusters as part of a search for post-starburst galaxies similar to those seen in distant Butcher-Oemler type clusters. Our earlier result of finding an area 0.5 Mpc SW of the Coma cluster core with a large fraction of starburst and post-starburst galaxies is solidified by the lack of such galaxies in a similar sized area to the NE of the Coma core. In DC2048-52, a cluster with substructure in the galaxy distribution as well as in the X-ray emission, we find that a significant fraction of the early-type galaxies in the northern substructure have had recent star formation, but that some galaxies in the central, dense part of the cluster also show spectral peculiarities. DC0326-53 has a significant though smaller number of peculiar early-type galaxies as well. The enhanced star formation in galaxies in these clusters provides interesting constraints on the continual formation of clusters through mergers of small groups with larger ones.

Long-slit spectra of several of the Coma post-starburst galaxies have been obtained which reveal that the the remnant A stars from the starbursts are distributed over large radii, rather than isolated to the nucleus. All of these Coma galaxies are disk systems, as indicated by their kinematics and their light distributions. These data comment on the origin of the starbursts themselves.

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