Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-10-24
Astronomy and Astrophysics
Astrophysics
accepted for publication in ApJL
Scientific paper
10.1086/338251
We discuss a correlation between star formation activity (SFA) and luminosity of star-forming galaxies at intermediate redshifts of $0.2\le z\le 0.6$ in both cluster and field environments. Equivalent width (EW) of [O{\sc ii}] is used for measurement of the SFA, and $R$-band absolute magnitude, $M_R$, for the luminosity. In less-luminous ($M_R \gsim -20.7$) galaxies, we find : (1) the mean EW([O{\sc ii}]) of cluster galaxies is smaller than that of field galaxies; but (2) some cluster galaxies have as large EW([O{\sc ii}]) as that of actively star-forming field galaxies. Based on both our results, we discuss a new possible mechanism for the Butcher-Oemler (BO) effect, assuming that the luminosity of a galaxy is proportional to its dynamical mass. Our proposal is that BO galaxies are less-massive cluster galaxies with smaller peculiar velocities. They are then stable against Kelvin-Helmholtz instability (KHI), and are not affected by tidal interaction between clusters and themselves. Their interstellar medium (ISM) would be hardly stripped, and their SFA would be little suppressed. Hence, as long as such galaxies keep up their SFA, the fraction of blue galaxies in a cluster does not decrease. As a cluster becomes virialized, however, such galaxies become more accelerated, the ISM available for SFA is stripped by KHI, and their color evolves redward, which produces the BO effect.
Kamaya Hideyuki
Tajiri Yuka Y.
No associations
LandOfFree
Anomalous Star-Formation Activity of Less-Luminous Galaxies in Cluster Environment does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Anomalous Star-Formation Activity of Less-Luminous Galaxies in Cluster Environment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anomalous Star-Formation Activity of Less-Luminous Galaxies in Cluster Environment will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-650843