The nature of luminous X-ray sources with mid-infrared counterparts

A. Alonso-Herrero, P. G. Pérez-González, J. Rigby, G. H. Rieke, E. Le Floc'h, P. Barmby, M. J. Page, C. Papovich, H. Dole, E. Egami, J. S. Huang, D. Rigopoulou, D. Cristóbal-Hornillos, C. Eliche-Moral, M. Balcells, M. Prieto, P. Erwin, C. W. Engelbracht, K. D. Gordon, M. WernerS. P. Willner, G. G. Fazio, D. Frayer, D. Hines, D. Kelly, W. Latter, K. Misselt, S. Miyazaki, J. Morrison, M. J. Rieke, G. Wilson

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


We investigate the luminous X-ray sources in the Lockman Hole (LH) and the extended Groth strip (EGS) detected at 24 μm using the Multiband Imaging Photometer (MIPS) and also with the Infrared Array Camera (IRAC) on board the Spitzer Space Telescope. We assemble optical/infrared spectral energy distributions (SEDs) for 45 X-ray/24 μm sources in the EGS and LH. Only about one-quarter of the hard X-ray/24 μm sources show pure type 1 active galactic nucleus (AGN) SEDs. More than half of the X-ray/24 μm sources have stellar emission-dominated or obscured SEDs, similar to those of local type 2 AGN and spiral/starburst galaxies. One-third of the sources detected in hard X-rays do not have a 24 μm counterpart. Two such sources in the LH have SEDs resembling those of S0/elliptical galaxies. The broad variety of SEDs in the optical-to-Spitzer bands of X-ray-selected AGNs means that AGNs selected according to the behavior in the optical/infrared will have to be supplemented by other kinds of data (e.g., X-ray) to produce unbiased samples of AGNs.

Original languageEnglish (US)
Pages (from-to)155-159
Number of pages5
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - Sep 2004


  • Galaxies: active
  • Galaxies: fundamental parameters
  • Infrared: galaxies
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • Luminous X-ray sources Chandra fluxes

    Alonso-Herrero, A. (Creator), Pérez-González, P. G. (Contributor), Rigby, J. (Creator), Rieke, G. H. (Creator), Le Floc'h, F. E. (Creator), Barmby, P. (Creator), Page, M. J. (Creator), Papovich, C. (Creator), Dole, H. (Creator), Egami, E. (Creator), Huang, J. (Creator), Rigopoulou, D. (Creator), Cristóbal-Hornillos, D. (Contributor), Eliche-Moral, C. (Creator), Balcells, M. (Creator), Prieto, M. (Creator), Erwin, P. (Creator), Engelbracht, C. W. (Creator), Gordon, K. D. (Creator), Werner, M. (Creator), Willner, S. P. (Creator), Fazio, G. G. (Creator), Frayer, D. (Creator), Hines, D. (Creator), Kelly, D. (Creator), Latter, W. (Creator), Misselt, K. (Creator), Miyazaki, S. (Creator), Morrison, J. (Creator), Rieke, M. J. (Creator), Wilson, G. (Creator), Barmby, P. (Creator), Prieto, M. (Creator), Werner, M. (Creator), Fazio, G. G. (Creator), Kelly, D. (Creator) & Wilson, G. (Creator), Centre de Donnees Strasbourg (CDS), 2005


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