AGN UNIFICATION AT z similar to 1: u - R COLORS AND GRADIENTS IN X-RAY AGN HOSTS

作者：Ammons S Mark^*; Rosario David J V; Koo David C; Dutton Aaron A; Melbourne Jason; Max Claire E; Mozena Mark; Kocevski Dale D; McGrath Elizabeth J; Bouwens Rychard J; Magee Daniel K

来源：Astrophysical Journal, 2011, 740(1): 3.

DOI：10.1088/0004-637X/740/1/3

• galaxies: active
• galaxies: evolution
• galaxies: photometry
• galaxies: stellar content
• X-rays: galaxies

We present uncontaminated rest-frame u - R colors of 78 X-ray-selected active galactic nucleus (AGN) hosts at 0.5 < z < 1.5 in the Chandra Deep Fields measured with Hubble Space Telescope (HST)/Advanced Camera for Surveys/NICMOS and Very Large Telescope/ISAAC imaging. We also present spatially resolved NUV - R color gradients for a subsample of AGN hosts imaged by HST/Wide Field Camera 3 (WFC3). Integrated, uncorrected photometry is not reliable for comparing the mean properties of soft and hard AGN host galaxies at z similar to 1 due to color contamination from point-source AGN emission. We use a cloning simulation to develop a calibration between concentration and this color contamination and use this to correct host galaxy colors. The mean u - R color of the unobscured/soft hosts beyond similar to 6 kpc is statistically equivalent to that of the obscured/hard hosts (the soft sources are 0.09 +/- 0.16 mag bluer). Furthermore, the rest-frame V - J colors of the obscured and unobscured hosts beyond similar to 6 kpc are statistically equivalent, suggesting that the two populations have similar distributions of dust extinction. For the WFC3/infrared sample, the mean NUV - R color gradients of unobscured and obscured sources differ by less than similar to 0.5 mag for r > 1.1 kpc. These three observations imply that AGN obscuration is uncorrelated with the star formation rate beyond similar to 1 kpc. These observations favor a unification scenario for intermediate-luminosity AGNs in which obscuration is determined geometrically. Scenarios in which the majority of intermediate-luminosity AGNs at z similar to 1 are undergoing rapid, galaxy-wide quenching due to AGN-driven feedback processes are disfavored.

• 出版日期2011-10-10