2026-06-27T13:59:46Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/519402023-08-26T11:37:37Zcom_20.500.14352_14col_20.500.14352_15

Donley, J. L. Rieke, G. H. Pérez González, Pablo Guillermo Rigby, J. R. Alonso Herrero, A. 2023-06-20T11:18:27Z 2023-06-20T11:18:27Z 2007-05-01 0004-637X 10.1086/512798 https://hdl.handle.net/20.500.14352/51940 http://dx.doi.org/10.1086/512798 http://iopscience.iop.org/ We define a sample of 62 galaxies in the Chandra Deep Field-North whose Spitzer IRAC SEDs exhibit the characteristic power-law emission expected of luminous AGNs. We study the multiwavelength properties of this sample and compare the AGNs selected in this way to those selected via other Spitzer color-color criteria. Only 55% of the power-law galaxies are detected in the X-ray catalog at exposures of >0.5 Ms, although a search for faint emission results in the detection of 85% of the power-law galaxies at the ≥2.5 σ detection level. Most of the remaining galaxies are likely to host AGNs that are heavily obscured in the X-ray. Because the power-law selection requires the AGNs to be energetically dominant in the near- and mid-infrared, the power-law galaxies comprise a significant fraction of the Spitzer-detected AGN population at high luminosities and redshifts. The high 24 μm detection fraction also points to a luminous population. The power-law galaxies comprise a subset of color-selected AGN candidates. A comparison with various mid-infrared color selection criteria demonstrates that while the color-selected samples contain a larger fraction of the X-ray-luminous AGNs, there is evidence that these selection techniques also suffer from a higher degree of contamination by star-forming galaxies in the deepest exposures. Considering only those power-law galaxies detected in the X-ray catalog, we derive an obscured fraction of 68% (2 : 1). Including all of the power-law galaxies suggests an obscured fraction of <81% (4 : 1). eng open access Spitzer power-law active galactic nucleus candidates in the chandra deep field-north journal article