Published by
EDP Sciences
EDP Sciences Journals List
Subscriber Authentication Point
Home All issues Volume 480/ 3 Article
Free access
Issue A&A
Volume 480, Number 3, March IV 2008
Page(s) L41 - L45
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20079200
Published online 07 February 2008



A&A 480, L41-L45 (2008)
DOI: 10.1051/0004-6361:20079200

Letter

Black hole growth and stellar assembly at high-z

M. Polletta1, 2

1  Institut d'Astrophysique de Paris (IAP), 98bis boulevard Arago, 75014 Paris, France
    e-mail: polletta@iap.fr
2  INAF - IASF Milano, via E. Bassini 15, 20133 Milan, Italy

(Received 5 December 2007 / Accepted 1 February 2008)

Abstract
Context.Observations indicate a strong link between star formation and black hole (BH) growth, but some questions remain unanswered: whether both activities are coeval or whether one precedes the other, what their characteristic timescales are, and what kinds of physical processes are responsible for this interplay.
Aims.We examine stellar and BH masses (M* and $M_{\rm BH}$) in $z \sim2$ active systems at the peak of their AGN or star formation activity to investigate how they are linked and whether AGN radiative or else radio power provides a feedback mechanism that regulates the stellar growth in these systems.
Methods.We analyze the infrared (IR) spectral energy distributions of radio, sub-millimeter and mid-IR selected AGNs at $z\sim1{-}3$ and constrain their stellar and AGN luminosities using AGN and host-galaxy templates.
Results.We find evidence of increasing stellar light, thereby decreasing the AGN mid-IR power going from mid-IR selected AGNs, to radio galaxies, and to sub-millimeter AGNs. This trend can be explained by either decreasing Eddington ratios or increasing offsets from the local $M_{\rm BH}{-}M_{*}$ relation. All systems are characterized by high star formation rates regardless of their different AGN powers, thus neither AGN radiative power nor AGN-driven radio activity seems to influence the star formation rate in the selected AGNs. We discuss two possible evolutionary scenarios that might link these three AGN classes.


Key words: galaxies: active -- galaxies: evolution -- galaxies: high-redshift -- quasars: general -- infrared: galaxies



© ESO 2008

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.