HerMES: Far-infrared properties of known AGN in the HerMES fields

E. Hatziminaoglou (1) , A. Omont (2) , J. A. Stevens , A. Amblard , V. Arumugam , R. Auld , H. Aussel (1) , T. Babbedge , A. Blain , J. Bock , A. Boselli (3) , V. Buat , D. Burgarella , N. Castro-Rodriguez , A. Cava (1) , P. Chanial (4) , D. L. Clements , A. Conley (5) , L. Conversi , A. Cooray , C. D. Dowell (1) , E. Dwek , S. Dye , S. Eales , D. Elbaz (6) , D. Farrah , M. Fox , A. Franceschini (7) , W. Gear , J. Glenn , E. A. Gonzalez Solares , M. Griffin (8) , M. Halpern , E. Ibar , K. Isaak , R. J. Ivison (9) , Guilaine Lagache , L. Levenson , N. Lu (10) , S. Madden , B. Maffei , G. Mainetti , L. Marchetti (11, 12) , A. M. J. Mortier , H. T. Nguyen (13, 14) , B. O'Halloran , S. J. Oliver , M. J. Page (15) , P. Panuzzo , A. Papageorgiou , C. P. Pearson (16) , I. Perez-Fournon , M. Pohlen , J. I. Rawlings , D. Rigopoulou , D. Rizzo , I. G. Roseboom , M. Rowan-Robinson , M. Sanchez Portal , B. Schulz , Douglas Scott , N. Seymour , D. L. Shupe , A. J. Smith (17) , M. Symeonidis , M. Trichas , K. E. Tugwell , M. Vaccari , I. Valtchanov (1) , L. Vigroux , L. Wang , R. Ward , Gavin Wright , C. K. Xu (18) , M. Zemcov (1)

1 AUTRES
2 IAP - Institut d'Astrophysique de Paris
3 LAM - Laboratoire d'Astrophysique de Marseille
4 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
5 Department of Astronomy and Astrophysics [Universty of Toronto]
6 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
7 LCMD - Laboratoire Colloïdes et Matériaux Divisés
8 School of Physics and Astronomy [Cardiff]
9 ROE - Royal Observatory Edinburgh
10 Division of Engineering
11 SCP - Service de Chimie Physique
12 SIMaP - Science et Ingénierie des Matériaux et Procédés
13 LPN - Laboratoire de photonique et de nanostructures
14 CRPP - Centre de recherches Paul Pascal
15 Department of Chemistry and Biochemistry
16 NIWA - National Institute of Water and Atmospheric Research [Wellington]
17 BAS - British Antarctic Survey
18 LMRS - Laboratoire de Mathématiques Raphaël Salem

Nuclear and starburst activity are known to often occur concomitantly. Herschel-SPIRE provides sampling of the FIR SEDs of type 1 and type 2 AGN, allowing for the separation between the hot dust (torus) and cold dust (starburst) emission. We study large samples of spectroscopically confirmed type 1 and type 2 AGN lying within the Herschel Multi-tiered Extragalactic Survey (HerMES) fields observed during the science demonstration phase, aiming to understand their FIR colour distributions and constrain their starburst contributions. We find that one third of the spectroscopically confirmed AGN in the HerMES fields have 5-sigma detections at 250um, in agreement with previous (sub)mm AGN studies. Their combined Spitzer-MIPS and Herschel-SPIRE colours - specifically S(250)/S(70) vs. S(70)/S(24) - quite clearly separate them from the non-AGN, star-forming galaxy population, as their 24-um flux is dominated by the hot torus emission. However, their SPIRE colours alone do not differ from those of non-AGN galaxies. SED fitting shows that all those AGN need a starburst component to fully account for their FIR emission. For objects at z > 2, we find a correlation between the infrared luminosity attributed to the starburst component, L(SB), and the AGN accretion luminosity, L(acc), with L(SB) propto L(acc)^0.35. Type 2 AGN detected at 250um show on average higher L(SB) than type 1 objects but their number is still too low to establish whether this trend indicates stronger star-formation activity.

Domaines: Astrophysique galactique [astro-ph.GA]; Astrophysique galactique [astro-ph.GA]

E. Hatziminaoglou, A. Omont, J. A. Stevens, A. Amblard, V. Arumugam, et al.. HerMES: Far-infrared properties of known AGN in the HerMES fields. 2010. ⟨hal-00662751⟩