Probing AGN triggering mechanisms through the starburstiness of the host galaxies

作者：Lamastra A^*; Menci N; Fiore F; Santini P; Bongiorno A; Piconcelli E

来源：Astronomy & Astrophysics, 2013, 559: A56.

DOI：10.1051/0004-6361/201322667

• galaxies: active
• galaxies: evolution
• galaxies: fundamental parameters
• galaxies: interactions
• galaxies: starburst

We estimate the fraction of AGNs hosted in starburst galaxies (f(bursty)) as a function of the AGN luminosity predicted under the assumption that starburst events and AGN activity are triggered by galaxy interactions during their merging histories. The latter are described through Monte Carlo realizations, and are connected to star formation and BH accretion using a semi-analytic model of galaxy formation in a cosmological framework. The predicted fraction f(bursty) increases steeply with AGN luminosity from. 0.2 at L-X less than or similar to 10(44) erg/s to greater than or similar to 0.9 at L-X greater than or similar to 10(45) erg/s over a wide redshift interval from z similar or equal to 0 to z similar or equal to 6. We compare the model predictions with new measurements of f(bursty) from a sample of X-ray selected AGNs in the XMM-COSMOS field at 0.3 < z < 2, and from a sample of QSOs (L-X greater than or similar to 10(45) erg /s) in the redshift range 2 < z < 6.5. We find preliminary indications that under conservative assumptions half of the QSO hosts are starburst galaxies. This result provides motivation for future systematic studies of the stellar properties of high luminosity AGN hosts in order to constrain AGN triggering mechanisms.

• 出版日期2013-11