AGN host galaxy mass function in COSMOS. Is AGN feedback responsible for the mass-quenching of galaxies?
Journal
Date Issued
2016
Author(s)
•
Schulze, A.
•
Merloni, A.
•
Zamorani, G.
•
Ilbert, O.
•
La Franca, F.
•
Peng, Y.
•
•
Mainieri, V.
•
Silverman, J. D.
•
Brusa, M.
•
•
Salvato, M.
•
Scoville, N.
Abstract
We investigate the role of supermassive black holes in the global context of galaxy evolution by measuring the host galaxy stellar mass function (HGMF) and the specific accretion rate, that is, λSAR, the distribution function (SARDF), up to z ~ 2.5 with ~1000 X-ray selected AGN from XMM-COSMOS. Using a maximum likelihood approach, we jointly fit the stellar mass function and specific accretion rate distribution function, with the X-ray luminosity function as an additional constraint. Our best-fit model characterizes the SARDF as a double power-law with mass-dependent but redshift-independent break, whose low λSAR slope flattens with increasing redshift while the normalization increases. This implies that for a given stellar mass, higher λSAR objects have a peak in their space density at earlier epoch than the lower λSAR objects, following and mimicking the well-known AGN cosmic downsizing as observed in the AGN luminosity function. The mass function of active galaxies is described by a Schechter function with an almost constant M∗⋆ and a low-mass slope α that flattens with redshift. Compared to the stellar mass function, we find that the HGMF has a similar shape and that up to log (M⋆/M☉) ~ 11.5, the ratio of AGN host galaxies to star-forming galaxies is basically constant (~10%). Finally, the comparison of the AGN HGMF for different luminosity and specific accretion rate subclasses with a previously published phenomenological model prediction for the "transient" population, which are galaxies in the process of being mass-quenched, reveals that low-luminosity AGN do not appear to be able to contribute significantly to the quenching and that at least at high masses, that is, M⋆ > 1010.7 M☉, feedback from luminous AGN (log Lbol ≳ 46 [erg/s]) may be responsible for the quenching of star formation in the host galaxy.
Volume
588
Start page
A78
Issn Identifier
0004-6361
Ads BibCode
2016A&A...588A..78B
Rights
open.access
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
aa27436-15.pdf
Description
pdf editoriale
Size
1.47 MB
Format
Adobe PDF
Checksum (MD5)
459b23bc4b97ab968f80c08d68b5a95d
Loading...
Name
1601.02091.pdf
Description
postprint
Size
1.04 MB
Format
Adobe PDF
Checksum (MD5)
4ea2958d182a15ee1f4bacf3f79735ef