Journal Article

The dependence of AGN activity on stellar and halo mass in semi-analytic models

Fabio Fontanot, Anna Pasquali, Gabriella De Lucia, Frank C. van den Bosch, Rachel S. Somerville and Xi Kang

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 2, pages 957-970
Published in print May 2011 | ISSN: 0035-8711
Published online April 2011 | e-ISSN: 1365-2966 | DOI:
The dependence of AGN activity on stellar and halo mass in semi-analytic models

More Like This

Show all results sharing this subject:

  • Astronomy and Astrophysics


Show Summary Details


Active galactic nuclei (AGN) feedback is believed to play an important role in shaping a variety of observed galaxy properties, as well as the evolution of their stellar masses and star formation rates. In particular, in the current theoretical paradigm of galaxy formation, AGN feedback is believed to play a crucial role in regulating star formation activity in galaxies residing in relatively massive haloes, at low redshift. Only in recent years, however, has detailed statistical information on the dependence of galaxy activity on stellar mass M*, parent halo MDM mass and hierarchy (i.e. centrals or satellites) become available. In this paper, we compare the fractions of galaxies belonging to different activity classes (star forming, AGN and radio active) with predictions from four different and independently developed semi-analytical models. We adopt empirical relations to convert physical properties into observables (Hα emission lines, O iii line strength and radio power). We demonstrate that all models used in this study reproduce the observed distributions of galaxies as a function of stellar mass and halo mass: star-forming galaxies and the strongest radio sources are preferentially associated with low-mass and high-mass galaxies/haloes, respectively. However, model predictions differ from observational measurements in many respects. All models used in our study predict that almost every MDM > 1012 M dark matter halo and/or M* > 1011 M galaxy should host a bright radio source, while only a small (few per cent) fraction of galaxies belong to this class in the data. In addition, radio brightness is expected to depend strongly on the mass of the parent halo mass in the models, while strong and weak radio galaxies are found in similar environments in data. Our results highlight that the distribution of AGN activity as a function of stellar mass provides one of the most promising discriminants between different gas accretion schemes.

Keywords: galaxies: active; galaxies: evolution; galaxies: formation

Journal Article.  10502 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.