Spatially Resolved Stellar Populations of Eight GOODS-South Active Galactic Nuclei at z ~ 1

Creators: Ammons, S. Mark; Melbourne, Jason; Max, Claire E.; Koo, David C.; Rosario, David J. V.

Abstract

We present a pilot study of the stellar populations of eight active galactic nucleus (AGN) hosts at z ~ 1 and compare with (1) lower redshift samples and (2) a sample of nonactive galaxies of similar redshift. We utilize K' images in the Great Observatories Origins Deep Survey South field obtained with the laser guide star adaptive optics system at Keck Observatory. We combine these K' data with B, V, i, and z imaging from the Advanced Camera for Surveys on Hubble Space Telescope to give multicolor photometry at a matched spatial resolution better than 100 mas in all bands. The hosts harbor AGNs as inferred from their high X-ray luminosities (LX > 10^42 erg s^–1) or mid-IR colors. We find a correlation between the presence of younger stellar populations and the strength of the AGN, as measured with [O III] line luminosity or X-ray (2-10 keV) luminosity. This finding is consistent with similar studies at lower redshift. Of the three Type II galaxies, two are disk galaxies and one is of irregular type, while in the Type I sample there are only one disk-like source and four sources with smooth, elliptical/spheroidal morphologies. In addition, the mid-IR spectral energy distributions of the strong Type II AGNs indicate that they are excited to Luminous InfraRed Galaxy (LIRG) status via galactic starbursting, while the strong Type I AGNs are excited to LIRG status via hot dust surrounding the central AGN. This supports the notion that the obscured nature of Type II AGNs at z ~ 1 is connected with global starbursting and that they may be extincted by kpc-scale dusty features that are by-products of this starbursting.

Additional Information

© 2009 The American Astronomical Society. Received 2008 May 28, accepted for publication 2008 October 21. Published 2008 December 19. Print publication: Issue 1 (2009 January). This work has been supported in part by the NSF Science and Technology Center for Adaptive Optics, managed by the University of California (UC) at Santa Cruz under the cooperative agreement No. AST-9876783. Some of the data presented in this paper were obtained from the Multimission Archive at the Space Telescope Science Institute (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts. The LGSAO system was funded by the W. M. Keck Foundation. The artificial laser guide star system was developed and integrated in a partnership between the Lawrence Livermore National Labs (LLNL) and the W. M. Keck Observatory. The laser was integrated at Keck with the help of Curtis Brown and Pamela Danforth. The NIRC2 near-infrared camera was developed by CalTech, UCLA, and Keck (PI Keith Matthews). The data presented herein were obtained at the Keck Observatory, which is operated as a scientific partnership among the CalTech, UC, and NASA. This work is supported in part under the auspices of the US Department of Energy, National Nuclear Security Administration and by LLNL under contract W-7405-Eng-48. S.M.A acknowledges fellowship support by the Allen family through UC Observatories/Lick Observatory. This work is based in part on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility. Observations have been carried out using the Very Large Telescope at the ESO Paranal Observatory under Program ID(s): LP168.A-0485. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this superb mountain. Facilities: CXO, HST, Keck:II, Spitzer, VLT:Antu

Attached Files

Published - AMMaj09.pdf

Files

AMMaj09.pdf

Files (13.2 MB)

Name	Size	Download all
AMMaj09.pdf md5:c6763e30b71b05906d0465744943a884	13.2 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes