Star formation in AGN hosts in GOODS-N

Journal article

Sensitive Herschel far-infrared observations can break degeneracies that were inherent to previous studies of star formation in high-z AGN hosts. Combining PACS 100 and 160 μm observations of the GOODS-N field with 2 Ms Chandra data, we detect ∼20% of X-ray AGN individually at >3σ. The host far-infrared luminosity of AGN with L2-10 keV ≈ 10 43 erg s-1 increases with redshift by an order of magnitude from z = 0 to z ∼ 1. In contrast, there is little dependence of far-infrared luminosity on AGN luminosity, for L2-10 keV10 44 erg s-1 AGN at z ≳ 1. We do not find a dependence of far-infrared luminosity on X-ray obscuring column, for our sample which is dominated by L2-10 keV < 1044 erg s-1 AGN. In conjunction with properties of local and luminous high-z AGN, we interpret these results as reflecting the interplay between two paths of AGN/host coevolution. A correlation of AGN luminosity and host star formation is traced locally over a wide range of luminosities and also extends to luminous high-z AGN. This correlation reflects an evolutionary connection, likely via merging. For lower AGN luminosities, star formation is similar to that in non-active massive galaxies and shows little dependence on AGN luminosity. The level of this secular, non-merger driven star formation increasingly dominates over the correlation at increasing redshift. © 2010 ESO.

Authors: Shao, L; Lutz, D; Nordon, R; Maiolino, R; Alexander, D

• Publication status: Published
• Journal: ASTRONOMY and ASTROPHYSICS
• Volume: 518
• Issue: 1
• Pages: L26-L26
• Publication date: 2010-01-01
• DOI: 10.1051/0004-6361/201014606
• EISSN: 1432-0746
• ISSN: 0004-6361
• Language: English
• Keywords: galaxies: active; infrared: galaxies