2012A&A...540A.109S


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.19CET15:05:44

2012A&A...540A.109S - Astronomy and Astrophysics, volume 540A, 109-109 (2012/4-1)

Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations.

SANTINI P., ROSARIO D.J., SHAO L., LUTZ D., MAIOLINO R., ALEXANDER D.M., ALTIERI B., ANDREANI P., AUSSEL H., BAUER F.E., BERTA S., BONGIOVANNI A., BRANDT W.N., BRUSA M., CEPA J., CIMATTI A., DADDI E., ELBAZ D., FONTANA A., FOERSTER SCHREIBER N.M., GENZEL R., GRAZIAN A., LE FLOC'H E., MAGNELLI B., MAINIERI V., NORDON R., PEREZ GARCIA A.M., POGLITSCH A., POPESSO P., POZZI F., RIGUCCINI L., RODIGHIERO G., SALVATO M., SANCHEZ-PORTAL M., STURM E., TACCONI L.J., VALTCHANOV I. and WUYTS S.

Abstract (from CDS):

We compare the average star formation (SF) activity in X-ray selected AGN hosts with a mass-matched control sample of inactive galaxies, including both star forming and quiescent sources, in the 0.5<z<2.5 redshift range. Recent observations carried out by PACS, the 60-210µm photometric camera on board the Herschel Space Observatory, in GOODS-S, GOODS-N and COSMOS allow us to obtain an unbiased estimate of the far-IR luminosity, and hence of the SF properties, of the two samples. Accurate AGN host stellar mass estimates are obtained by decomposing their total emission into the stellar and the nuclear components. We report evidence of a higher average SF activity in AGN hosts with respect to the control sample of inactive galaxies. The level of SF enhancement is modest (∼0.26dex at ∼3σ confidence level) at low X-ray luminosities (LX λ1043.5 erg/s) and more pronounced (0.56dex at >10σ confidence level) in the hosts of luminous AGNs. However, when comparing to star forming galaxies only, AGN hosts are found broadly consistent with the locus of their ``main sequence''. We investigate the relative far-IR luminosity distributions of active and inactive galaxies, and find a higher fraction of PACS detected, hence normal and highly star forming systems among AGN hosts. Although different interpretations are possible, we explain our findings as a consequence of a twofold AGN growth path: faint AGNs evolve through secular processes, with instantaneous AGN accretion not tightly linked to the current total SF in the host galaxy, while the luminous AGNs co-evolve with their hosts through periods of enhanced AGN activity and star formation, possibly through major mergers. While an increased SF activity with respect to inactive galaxies of similar mass is expected in the latter, we interpret the modest SF offsets measured in low-LX AGN hosts as either a) generated by non-synchronous accretion and SF histories in a merger scenario or b) due to possible connections between instantaneous SF and accretion that can be induced by smaller scale (non-major merger) mechanisms. Far-IR luminosity distributions favour the latter scenario.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: evolution - galaxies: high-redshift - galaxies: star formation - infrared: galaxies

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Chandra Deep Field-South reg 03 32 28.0 -27 48 30           ~ 1753 1
2 NAME GOODS Southern Field reg 03 32 28.0 -27 48 30           ~ 999 1
3 NAME COSMOS Field reg 10 00 28.60 +02 12 21.0           ~ 1895 0
4 NAME GOODS-N Field reg 12 36 55.0 +62 14 15           ~ 877 1

    Equat.    Gal    SGal    Ecl

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2019.11.19-15:05:44

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