2010A&A...518L..18S


Query : 2010A&A...518L..18S

2010A&A...518L..18S - Astronomy and Astrophysics, volume 518, L18-18 (2010/7-2)

LoCuSS: probing galaxy transformation physics with Herschel.

SMITH G.P., HAINES C.P., PEREIRA M.J., EGAMI E., MORAN S.M., HARDEGREE-ULLMAN E., BABUL A., REX M., RAWLE T.D., ZHANG Y.-Y., FINOGUENOV A., OKABE N., SANDERSON A.J.R., EDGE A.C. and TAKADA M.

Abstract (from CDS):

We present an early broad-brush analysis of Herschel/PACS observations of star-forming galaxies in 8 galaxy clusters drawn from our survey of 30 clusters at z ≃0.2. We define a complete sample of 192 spectroscopically confirmed cluster members down to L_ TIR>3x1010^L and LK>0.25LK*. The average K-band and bolometric infrared luminosities of these galaxies both fade by a factor of ∼2 from clustercentric radii of ∼2r200 to ∼0.5r200, indicating that as galaxies enter the clusters ongoing star-formation stops first in the most massive galaxies, and that the specific star-formation rate (SSFR) is conserved. On smaller scales the average SSFR jumps by ∼25%, suggesting that in cluster cores processes including ram pressure stripping may trigger a final episode of star-formation that presumably exhausts the remaining gas. This picture is consistent with our comparison of the Herschel-detected cluster members with the cluster mass distributions, as measured in our previous weak-lensing study of these clusters. For example, the spatial distribution of the Herschel sources is positively correlated with the structures in the weak-lensing mass maps at ∼5σ significance, with the strongest signal seen at intermediate group-like densities. The strong dependence of the total cluster IR luminosity on cluster mass - LTIR∝Mvirial2 - is also consistent with accretion of galaxies and groups of galaxies (i.e. the substructure mass function) driving the cluster IR luminosity. The most surprising result is that roughly half of the Herschel-detected cluster members have redder S100/S24 flux ratios than expected, based on the Rieke et al. models. On average cluster members are redder than non-members, and the fraction of red galaxies increases towards the cluster centers, both of which indicate that these colors are not attributable to systematic photometric errors. Our future goals include to intepret physically these red galaxies, and to exploit this unique large sample of clusters with unprecedented multi-wavelength observations to measure the cluster-cluster scatter in S0 progenitor populations, and to intepret that scatter in the context of the hierarchical assembly of clusters.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: general - galaxies: star formation - Galaxy: evolution - infrared: galaxies

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 ClG 0657-56 ClG 06 58 29.6 -55 56 39           ~ 890 1
2 ACO 1689 ClG 13 11 29.5 -01 20 28           ~ 1084 0
3 ACO 1758 ClG 13 32 32.1 +50 30 37           ~ 242 2
4 ACO 1763 ClG 13 35 20.1 +41 00 04           ~ 292 0
5 ACO 1835 ClG 14 01 02.07 +02 52 43.2           ~ 663 1
6 NAME SMM J14010+0252 Sy1 14 01 02.0819944848 +02 52 42.426538140   19.3       ~ 45 2
7 ACO 1914 ClG 14 26 01.3 +37 49 36           ~ 297 0
8 ZwCl 1455+2232 ClG 14 57 15.2 +22 20 30     18.62 20.04   ~ 279 0
9 ACO 2219 ClG 16 40 22.1 +46 42 20           ~ 345 0
10 ACO 2390 ClG 21 53 34.6 +17 40 11           ~ 660 2
11 NAME SMM J21536+1741 BiC 21 53 36.82670 +17 41 43.7260     19.58     ~ 41 2

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2022.11.29-16:14:18

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