Optically-passive spirals: The missing link in gradual star formation suppression upon cluster infall

Wolf, Christian; Aragón-Salamanca, Alfonso;Balogh, Michael; Barden, Marco; Bell, Eric F.;Gray, Meghan E.; Peng, Chien Y.; Bacon, David;Barazza, Fabio D.; Böhm, Asmus; Caldwell, John A. R.;Gallazzi, Anna; Häu\ss ler, Boris;Heymans, Catherine; Jahnke, Knud; Jogee, Shardha;van Kampen, Eelco; Lane, Kyle; McIntosh, Daniel H.;Meisenheimer, Klaus; Papovich, Casey;Sánchez, Sebastian F.; Taylor, Andy; Wisotzki, Lutz;Zheng, Xianzhong. Optically-passive spirals: The missing link in gradual star formation suppression upon cluster infall. eprint arXiv:0906.0306. 2009, Vol. , p. -2009.

Galaxies migrate from the blue cloud to the red sequence when their star
formation is quenched. Here, we report on galaxies quenched by
environmental effects and not by mergers or strong AGN as often invoked:
They form stars at a reduced rate which is optically even less
conspicuous, and manifest a transition population of blue spirals
evolving into S0 galaxies. These 'optically passive' or 'red spirals'
are found in large numbers in the STAGES project (and by Galaxy Zoo) in
the infall region of clusters and groups.