The Optical Spectra of 24 ?m Galaxies in the COSMOS Field. I. Spitzer MIPS Bright Sources in the zCOSMOS-Bright 10k Catalog

K. I. Caputi , S. J. Lilly , H. Aussel , D. Sanders , D. Frayer , O. Le Fèvre (1) , A. Renzini , G. Zamorani , M. Scodeggio , T. Contini (2) , N. Scoville , C. M. Carollo , G. Hasinger , A. Iovino , V. Le Brun (1) , E. Le Floc'H , C. Maier , V. Mainieri , M. Mignoli , M. Salvato , David Schiminovich (3) , J. Silverman , J. Surace (4) , L. Tasca (1) , U. Abbas , S. Bardelli , M. Bolzonella , A. Bongiorno (5) , D. Bottini (6) , P. Capak , A. Cappi (6) , P. Cassata , Alessandro Cimatti , O. Cucciati (7) , S. de La Torre , L. de Ravel , P. Franzetti (6) , M. Fumana , B. Garilli (6) , C. Halliday , O. Ilbert , P. Kampczyk , J. Kartaltepe , J.-P. Kneib (2) , C. Knobel , K. Kovac , F. Lamareille (2) , A. Leauthaud (1) , J. F. Le Borgne (2) , D. Maccagni (6) , Christian Marinoni (1) , H. Mccracken (8) , B. Meneux (1) , P. Oesch , R. Pellò (2) , E. Pérez-Montero , C. Porciani , E. Ricciardelli , R. Scaramella (6) , C. Scarlata , L. Tresse (1) , D. Vergani (9) , J. Walcher , M. Zamojski , E. Zucca (6)

1 LAM - Laboratoire d'Astrophysique de Marseille
2 LATT - Laboratoire Astrophysique de Toulouse-Tarbes
3 CALTECH - California Institute of Technology
4 AUTRES
5 UNIBO - Alma Mater Studiorum Università di Bologna = University of Bologna
6 OABO - INAF - Osservatorio Astronomico di Bologna
7 OAB - INAF - Osservatorio Astronomico di Brera
8 IAP - Institut d'Astrophysique de Paris
9 Institute of Liver Studies

We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24 ?m-selected galaxies with S24?m>0.30 mJy and I<22.5 (AB mag) over 1.5 deg2 of the COSMOS field. From emission-line diagnostics we find the following: (1) SFRs derived from the observed H? ?6563 and H? ?4861 lines underestimate, on average, the total SFR by factors of ~5 and 10, respectively. (2) Both the Calzetti et al. and the Milky Way reddening laws are suitable to describe the extinction observed in IR sources in most cases. (3) Some IR galaxies at z<0.3 have low abundances, but many others with similar IR luminosities and redshifts are chemically enriched. (4) The average [O III] ?5007/H? ?4861 ratios of ?L24?m?>1011 Lsolar galaxies at 0.6

Mots clés: Galaxies: Abundances; Galaxies: Active; Galaxies: Evolution; Infrared: Galaxies

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

K. I. Caputi, S. J. Lilly, H. Aussel, D. Sanders, D. Frayer, et al.. The Optical Spectra of 24 ?m Galaxies in the COSMOS Field. I. Spitzer MIPS Bright Sources in the zCOSMOS-Bright 10k Catalog. The Astrophysical Journal, 2008, 680, pp.939-961. ⟨10.1086/588038⟩. ⟨hal-00288465⟩