Effect of the star formation histories on the SFR-M_∗ relation at z ≥ 2

¹ INAF–IASF Milano, via Bassini 15, 20133 Milano, Italy
e-mail: letizia.cassara@gmail.com
² INAF–Osservatorio Astronomico di Bologna, via Ranzani,1, 40127 Bologna, Italy
³ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
⁴ INAF–Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy
⁵ University of Bologna, Department of Physics and Astronomy (DIFA), V.le Berti Pichat, 6/2, 40127 Bologna, Italy
⁶ INAF–IASF Bologna, via Gobetti 101, 40129 Bologna, Italy
⁷ Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis boulevard Arago, 75014 Paris, France
⁸ Institut de Recherche en Astrophysique et Planétologie – IRAP, CNRS, Université de Toulouse, UPS-OMP, 14, avenue E. Belin, 31400 Toulouse, France
⁹ Department of Astronomy, University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland
¹⁰ Geneva Observatory, University of Geneva, ch. des Maillettes 51, 1290 Versoix, Switzerland
¹¹ Centro de Estudios de Física del Cosmos de Aragón, 44001 Teruel, Spain
¹² Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., MC 249–17, Pasadena, CA 91125, USA
¹³ Astronomy Department, University of Massachusetts, Amherst, MA 01003, USA
¹⁴ Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, 85741 Garching bei München, Germany
¹⁵ Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, 790-8577 Matsuyama, Japan
¹⁶ SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ, UK
¹⁷ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹⁸ Instituto de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso, Chile
¹⁹ Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Penteli, 15236 Athens, Greece

Received: 9 May 2015
Accepted: 15 June 2016

Abstract

We investigate the effect of different star formation histories (SFHs) on the relation between stellar mass (M_∗) and star formation rate (SFR) using a sample of galaxies with reliable spectroscopic redshift z_spec> 2 drawn from the VIMOS Ultra-Deep Survey (VUDS). We produce an extensive database of dusty model galaxies, calculated starting from a new library of single stellar population (SSPs) models, weighted by a set of 28 different star formation histories based on the Schmidt function, and characterized by different ratios of the gas infall timescale τ_infall to the star formation efficiency ν. Dust extinction and re-emission were treated by means of the radiative transfer calculation. The spectral energy distribution (SED) fitting technique was performed by using GOSSIP+, a tool able to combine both photometric and spectroscopic information to extract the best value of the physical quantities of interest, and to consider the intergalactic medium (IGM) attenuation as a free parameter. We find that the main contribution to the scatter observed in the SFR-M_∗ plane is the possibility of choosing between different families of SFHs in the SED fitting procedure, while the redshift range plays a minor role. The majority of the galaxies, at all cosmic times, are best fit by models with SFHs characterized by a high τ_infall/ν ratio. We discuss the reliability of a low percentage of dusty and highly star-forming galaxies in the context of their detection in the far infrared (FIR).