Ongoing and co-evolving star formation in zCOSMOS galaxies hosting Active Galactic Nuclei
Abstract
We present a study of the host galaxies of AGN selected from the zCOSMOS survey to establish if accretion onto supermassive black holes and star formation are explicitly linked up to z~1. We identify 152 galaxies that harbor AGN, based on XMM observations of 7543 galaxies (i<22.5). Star formation rates (SFRs), including those weighted by stellar mass, are determined using the [OII]3727 emission-line, corrected for an AGN contribution. We find that the majority of AGN hosts have significant levels of star formation with a distribution spanning ~1-100 Msun yr^-1. The close association between AGN activity and star formation is further substantiated by an increase in the AGN fraction with the youthfulness of their stars as indicated by the rest-frame color (U-V) and spectral index Dn(4000); we demonstrate that mass-selection alleviates an artifical peak falling in the transition region when using luminosity-limited samples. We also find that the SFRs of AGN hosts evolve with cosmic time in a manner that closely mirrors the overall galaxy population and explains the low SFRs in AGNs (z<0.3) from the SDSS. We conclude that the conditions most conducive for AGN activity are a massive host galaxy and a large reservoir of gas. Furthermore, a direct correlation between mass accretion rate onto SMBHs and SFR is shown to be weak although the average ratio is constant with redshift, effectively shifting the evidence for a co-evolution scenario in a statistical manner to smaller physical scales. Our findings illustrate an intermittent scenario with an AGN lifetime substantially shorter than that of star formation and underlying complexities regarding fueling over vastly different physical scales yet to be determined [Abridged].
Keywords
Cite
@article{arxiv.0810.3653,
title = {Ongoing and co-evolving star formation in zCOSMOS galaxies hosting Active Galactic Nuclei},
author = {J. D. Silverman and F. Lamareille and C. Maier and S. Lilly and V. Mainieri and M. Brusa and N. Cappelluti and G. Hasinger and G. Zamorani and M. Scodeggio and M. Bolzonella and T. Contini and C. M. Carollo and K. Jahnke and J. -P. Kneib and O. Le Fevre and A. Merloni and S. Bardelli and A. Bongiorno and H. Brunner and K. Caputi and F. Civano and A. Comastri and G. Coppa and O. Cucciati and S. de la Torre and L. de Ravel and M. Elvis and A. Finoguenov and F. Fiore and P. Franzetti and B. Garilli and R. Gilli and A. Iovino and P. Kampczyk and C. Knobel and K. Kovac and J. -F. Le Borgne and V. Le Brun and M. Mignoli and R. Pello and Y. Peng and E. Perez Montero and E. Ricciardelli and M. Tanaka and L. Tasca and L. Tresse and D. Vergani and C. Vignali and E. Zucca and D. Bottini and A. Cappi and P. Cassata and M. Fumana and R. Griffiths and J. Kartaltepe and C. Marinoni and H. J. McCracken and P. Memeo and B. Meneux and P. Oesch and C. Porciani and M. Salvato},
journal= {arXiv preprint arXiv:0810.3653},
year = {2014}
}
Comments
To appear in The Astrophysical Journal; 17 pages; 13 figures (5 color)