AGN UNIFICATION AT z {approx} 1: u - R COLORS AND GRADIENTS IN X-RAY AGN HOSTS
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching (Germany)
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 {approx} 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 {approx}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 {approx}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 {approx}0.5 mag for r > 1.1 kpc. These three observations imply that AGN obscuration is uncorrelated with the star formation rate beyond {approx}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 {approx} 1 are undergoing rapid, galaxy-wide quenching due to AGN-driven feedback processes are disfavored.
- OSTI ID:
- 21587447
- Journal Information:
- Astrophysical Journal, Vol. 740, Issue 1; Other Information: DOI: 10.1088/0004-637X/740/1/3; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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