Sub-Arcsecond Mid-Infrared Observations of NGC 6240: Limitations of AGN-Starburst Power Diagnostics

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dc.creatorEgami, E.
dc.creatorNeugebauer, G.
dc.creatorSoifer, B. T.
dc.creatorMatthews, K.
dc.creatorBecklin, E. E.
dc.creatorRessler, M. E.
dc.date2005-11-09
dc.date.accessioned2026-07-07T11:24:57Z
dc.date.available2026-07-07T11:24:57Z
dc.descriptionIn order to examine the relative importance of powerful starbursts and Compton-thick AGNs in NGC 6240, we have obtained mid-infrared images and low-resolution spectra of the galaxy with sub-arcsecond spatial resolution using the Keck Telescopes. Despite the high spatial resolution (~200 pc) of our data, no signature of the hidden AGNs has been detected in the mid-infrared. The southern nucleus, which we show provides 80-90% of the total 8-25 um luminosity of the system, has a mid-infrared spectrum and a mid-/far-infrared spectral energy distribution consistent with starbursts. At the same time, however, it is also possible to attribute up to 60% of the bolometric luminosity to an AGN, consistent with X-ray observations, if the AGN is heavily obscured and emits mostly in the far-infrared. This ambiguity arises because the intrinsic variation of properties among a given galaxy population (e.g., starbursts) introduces at least a factor of a few uncertainty even into the most robust AGN-starburst diagnostics. We conclude that with present observations it is not possible to determine the dominant power source in galaxies when AGN and starburst luminosities are within a factor of a few of each other.
dc.description27 pages, 7 figures, 2 tables; Accepted for publication in AJ
dc.identifierhttps://arxiv.org/abs/astro-ph/0511282
dc.identifierhttp://arxiv.org/abs/astro-ph/0511282
dc.identifierAstron.J.131:1253-1261,2006
dc.identifierdoi:10.1086/499524
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195365
dc.subjectAstrophysics
dc.titleSub-Arcsecond Mid-Infrared Observations of NGC 6240: Limitations of AGN-Starburst Power Diagnostics
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