AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies

Details AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies

2011-11-29

arxiv.org/abs/1111.6693v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

46 pages, 25 figures, accepted for publication in ApJ

Scientific paper

We present the mid-infrared (MIR) properties of galaxies within a supercluster in the North Ecliptic Pole region at z?0.087 observed with the AKARI satellite. We use data from the AKARI NEP-Wide (5.4 deg2) IR survey and the CLusters of galaxies EVoLution studies (CLEVL) mission program. We show that near-IR (3 {\mu}m)-mid- IR (11 {\mu}m) color can be used as an indicator of the specific star formation rate and the presence of intermediate age stellar populations. From the MIR observations, we find that red-sequence galaxies consist not only of passively evolving red early-type galaxies, but also of 1) "weak-SFG" (disk-dominated star-forming galaxies which have star formation rates lower by \sim 4 \times than blue-cloud galaxies), and 2) "intermediate- MXG" (bulge-dominated galaxies showing stronger MIR dust emission than normal red early-type galaxies). Those two populations can be a set of transition galaxies from blue, star-forming, late-type galaxies evolving into red, quiescent, early-type ones. We find that the weak-SFG are predominant at intermediate masses (1010M\odot < M\star < 1010.5M\odot) and are typically found in local densities similar to the outskirts of galaxy clusters. As much as 40% of the supercluster member galaxies in this mass range can be classified as weak-SFGs, but their proportion decreases to < 10% at larger masses (M\star > 1010.5 M\odot) at any galaxy density. The fraction of the intermediate-MXG among red- sequence galaxies at 1010M\odot < M\star < 1011M\odot also decreases as the density and mass increase. In particular, \sim42% of the red-sequence galaxies with early-type morphologies are classified as intermediate-MXG at intermediate densities. These results suggest that the star formation activity is strongly dependent on the stellar mass, but that the morphological transformation is mainly controlled by the environment.

Affiliated with

Also associated with

No associations

Rating

AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies 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 AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and AKARI Observation of the North Ecliptic Pole (NEP) Supercluster at z = 0.087: mid-infrared view of transition galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-14810