A&A 492, 371-388 (2008)
DOI: 10.1051/0004-6361:200810435

IMAGES IV: strong evolution of the oxygen abundance in gaseous phases of intermediate mass galaxies from z ~ 0.8

M. Rodrigues^{1, 2}, F. Hammer¹, H. Flores¹, M. Puech^{3, 1}, Y. C. Liang⁴, I. Fuentes-Carrera¹, N. Nesvadba¹, M. Lehnert¹, Y. Yang¹, P. Amram⁵, C. Balkowski¹, C. Cesarsky¹, H. Dannerbauer⁶, R. Delgado^{1, 7}, B. Guiderdoni⁸, A. Kembhavi⁹, B. Neichel¹, G. Östlin¹⁰, L. Pozzetti¹¹, C. D. Ravikumar¹², A. Rawat^{1, 9}, S. di Serego Alighieri¹³, D. Vergani^{14, 11}, J. Vernet³, and H. Wozniak<sup>8

1</sup>  GEPI , Observatoire de Paris, CNRS, University Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France
    e-mail: myriam.rodrigues@obspm.fr
²  CENTRA, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisboa, Portugal
³  ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
⁴  National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, PR China
⁵  Laboratoire d'Astrophysique de Marseille, Observatoire Astronomique de Marseille-Provence, 2 place Le Verrier, 13248 Marseille, France
⁶  MPIA, Königstuhl 17, 69117 Heidelberg, Germany
⁷  IFARHU-SENACYT, Technological University of Panama, 0819-07289 Panama, Rep. of Panama
⁸  Centre de Recherche Astronomique de Lyon, 9 Avenue Charles André, 69561 Saint-Genis-Laval Cedex, France
⁹  Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007, India
¹⁰  Stockholm Observatory, AlbaNova University Center, Stockholms Center for Physics, Astronomy and Biotechnology, Roslagstullsbacken 21, 10691 Stockholm, Sweden
¹¹  INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
¹²  Department of Physics, University of Calicut, Kerala 673635, India
¹³  INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Florence, Italy
¹⁴  IASF-INAF - via Bassini 15, 20133 Milano, Italy

Received 20 June 2008 / Accepted 21 September 2008

Abstract
Context. Intermediate mass galaxies (> 10¹⁰ ) at z ~ 0.6 are the likeliest progenitors of the present-day, numerous population of spirals. There is growing evidence that they have evolved rapidly in the last 6 to 8 Gyr, and likely already have formed a significant fraction of their stellar mass, often showing perturbed morphologies and kinematics.
Aims. We have gathered a representative sample of 88 such galaxies and have provided robust estimates of their gas phase metallicity.
Methods. We used moderate spectral resolution spectroscopy at VLT/FORS2 with an unprecedentedly high S/N allowing us to remove biases coming from interstellar absorption lines and extinction, to establish robust values of R₂₃ = ([OII]3727 + [OIII]4959, 5007)/H.
Results. We definitively confirm that the predominant population of z ~ 0.6 starbursts and luminous IR galaxies (LIRGs) are on average two times less metal rich than the local galaxies at a given stellar mass. We do find that the metal abundance of the gaseous phase of galaxies evolves linearly with time, from z = 1 to z = 0 and after comparing with other studies, from z = 3 to z = 0. Combining our results with the reported evolution of the Tully Fisher relation, we find that such an evolution requires that ~30% of the stellar mass of local galaxies have been formed through an external supply of gas, thus excluding the closed box model. Distant starbursts & LIRGs have properties (metal abundance, star formation efficiency & morphologies) similar to those of local LIRGs. Their underlying physics is likely dominated by gas infall, probably through merging or interactions.
Conclusions. Our study further supports the rapid evolution of z ~ 0.4–1 galaxies. Gas exchange between galaxies is likely the main cause of this evolution.

Key words: galaxies: evolution -- galaxies: ISM -- galaxies: spiral -- galaxies: starburst -- infrared: galaxies

© ESO 2008

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