Deep Herschel view of obscured star formation in the Bullet cluster

T. D. Rawle (1) , S. M. Chung (2) , D. Fadda (2) , M. Rex (3) , E. Egami (1) , P. G. Pérez-González (4) , B. Altieri (5) , A. W. Blain (6) , C. R. Bridge (6) , A. K. Fiedler (2) , A. H. Gonzalez (2) , M. J. Pereira (1) , J. Richard (7) , I. Smail (8) , I. Valtchanov (2) , M. Zemcov (2) , P. N. Appleton (2) , J. J. Bock (2) , F. Boone (9) , B. Clement (10) , F. Combes (11) , C. D. Dowell (2) , M. Dessauges-Zavadsky (12) , O. Ilbert (10) , R. J. Ivison (13) , M. Jauzac (10) , J.-P. Kneib (10) , D. Lutz (14) , R. Pelló (9) , G. H. Rieke (1) , G. Rodighiero (2) , D. Schaerer (9) , G. P. Smith (15) , G. L. Walth (1) , P. van Der Werf (16) , M. W. Werner (2)

1 Steward Observatory
2 AUTRES
3 AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine
4 Departamento de Física y Astronomía
5 XMM-Newton Science Operations Centre
6 Department of Astronomy
7 CRAL - Centre de Recherche Astrophysique de Lyon
8 ICC - Institute for Computational Cosmology
9 IRAP - Institut de recherche en astrophysique et planétologie
10 LAM - Laboratoire d'Astrophysique de Marseille
11 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
12 ObsGE - Observatoire Astronomique de l'Université de Genève
13 ROE - Royal Observatory Edinburgh
14 MPE - Max-Planck-Institut für Extraterrestrische Physik
15 UAB - University of Alabama at Birmingham [ Birmingham]
16 Leiden Observatory [Leiden]

We use deep, five band (100-500 μm) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFRFIR, of galaxies in the Bullet cluster (z = 0.296), and a smaller background system (z = 0.35) in the same field. Herschel detects 23 Bullet cluster members with a total SFRFIR = 144±14 M&sun; yr-1. On average, the background system contains brighter far-infrared (FIR) galaxies, with ~50% higher SFRFIR (21 galaxies; 207± 9 M&sun; yr-1). SFRs extrapolated from 24 μm flux via recent templates (SFR24 µm) agree well with SFRFIR for ~60% of the cluster galaxies. In the remaining ~40%, SFR24 µm underestimates SFRFIR due to a significant excess in observed S100/S24 (rest frame S75/S18) compared to templates of the same FIR luminosity. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. Data presented in this paper were analyzed using "The Herschel Interactive Processing Environment (HIPE)", a joint development by the Herschel Science Ground Segment Consortium, consisting of ESA, the NASA Herschel Science Center, and the HIFI, PACS and SPIRE consortia.

Mots clés: galaxies: clusters: individual: Bullet cluster; galaxies: star formation; infrared: galaxies; submillimeter: galaxies

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

T. D. Rawle, S. M. Chung, D. Fadda, M. Rex, E. Egami, et al.. Deep Herschel view of obscured star formation in the Bullet cluster. Astronomy and Astrophysics - A&A, 2010, 518, pp.L14. ⟨10.1051/0004-6361/201014681⟩. ⟨hal-00660712⟩