The STAGES view of red spirals and dusty red galaxies: mass-dependent quenching of star formation in 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; Häußler, 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. The STAGES view of red spirals and dusty red galaxies: mass-dependent quenching of star formation in cluster infall. Monthly Notices of the Royal Astronomical Society. 2009, Vol. Volume 393, Issue 4, pp. 1302-1323., p. -2009.
We investigate the properties of optically passive spirals and dusty red
galaxies in the A901/2 cluster complex at redshift ~0.17 using
rest-frame near-ultraviolet-optical spectral energy distributions,
24-μm infrared data and Hubble Space Telescope morphologies from the
STAGES data set. The cluster sample is based on COMBO-17 redshifts with
an rms precision of σ<SUB>cz</SUB> ~ 2000kms<SUP>-1</SUP>. We find
that `dusty red galaxies' and `optically passive spirals' in A901/2 are
largely the same phenomenon, and that they form stars at a substantial
rate, which is only four times lower than that in blue spirals at fixed
mass. This star formation is more obscured than in blue galaxies and its
optical signatures are weak. They appear predominantly in the stellar
mass range of logM<SUB>*</SUB>/M<SUB>solar</SUB> = [10, 11] where they
constitute over half of the star-forming galaxies in the cluster; they
are thus a vital ingredient for understanding the overall picture of
star formation quenching in clusters. We find that the mean specific
star formation rate (SFR) of star-forming galaxies in the cluster is
clearly lower than in the field, in contrast to the specific SFR
properties of blue galaxies alone, which appear similar in cluster and
field. Such a rich red spiral population is best explained if quenching
is a slow process and morphological transformation is delayed even more.
At logM<SUB>*</SUB>/M<SUB>solar</SUB> < 10, such galaxies are rare,
suggesting that their quenching is fast and accompanied by morphological
change. We note that edge-on spirals play a minor role; despite being
dust reddened they form only a small fraction of spirals independent of
environment.
We investigate the properties of optically passive spirals and dusty red
galaxies in the A901/2 cluster complex at redshift ~0.17 using
rest-frame near-ultraviolet-optical spectral energy distributions,
24-μm infrared data and Hubble Space Telescope morphologies from the
STAGES data set. The cluster sample is based on COMBO-17 redshifts with
an rms precision of σ<SUB>cz</SUB> ~ 2000kms<SUP>-1</SUP>. We find
that `dusty red galaxies' and `optically passive spirals' in A901/2 are
largely the same phenomenon, and that they form stars at a substantial
rate, which is only four times lower than that in blue spirals at fixed
mass. This star formation is more obscured than in blue galaxies and its
optical signatures are weak. They appear predominantly in the stellar
mass range of logM<SUB>*</SUB>/M<SUB>solar</SUB> = [10, 11] where they
constitute over half of the star-forming galaxies in the cluster; they
are thus a vital ingredient for understanding the overall picture of
star formation quenching in clusters. We find that the mean specific
star formation rate (SFR) of star-forming galaxies in the cluster is
clearly lower than in the field, in contrast to the specific SFR
properties of blue galaxies alone, which appear similar in cluster and
field. Such a rich red spiral population is best explained if quenching
is a slow process and morphological transformation is delayed even more.
At logM<SUB>*</SUB>/M<SUB>solar</SUB> < 10, such galaxies are rare,
suggesting that their quenching is fast and accompanied by morphological
change. We note that edge-on spirals play a minor role; despite being
dust reddened they form only a small fraction of spirals independent of
environment.