Selecting Seyfert galaxies with nuclear AGN-dominated emission

J. García-González, A. Alonso-Herrero, A. Hernán-Caballero, M. Pereira-Santaella, C. Ramos-Almeida, J. A. Acosta-Pulido, T. Díaz-Santos, P. Esquej, O. González-Martín, K. Ichikawa, E. López-Rodríguez, M. Povic, P. F. Roche, M. Sánchez-Portal

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We present far-infrared (FIR) 70 - 500 μm imaging observations obtained with Herschel/PACS and SPIRE of 33 nearby (median distance of 30 Mpc) Seyfert galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR nuclear (r = 1 kpc and r = 2 kpc) and integrated spectral energy distributions (SEDs). We estimate the unresolved nuclear emission at 70 μm and we fit the nuclear and integrated FIR SEDs with a grey body model. We find that the integrated FIR emission of the RSA Seyferts in our sample is dominated by emission from the host galaxy, with dust properties similar to those of normal galaxies (non AGN). We use four criteria to select galaxies whose nuclear 70 μm emission is dominated by the AGN: (1) elevated 70/160 μm flux ratios, (2) spatially resolved, high dust temperature gradient, (3) 70 μm excess emission with respect to the fit of the FIR SEDs with a grey body, and (4) excess of nuclear SFR obtained from 70 μm over SFR from mid-infrared indicators. 16 galaxies (48 per cent of the initial sample) satisfy at least one of these conditions, whereas 10 satisfy half or more. After careful examination of these, we select six bona fide candidates (18 per cent of the initial sample) and estimate that ∼40 - 70 per cent of their nuclear (r = 1 - 2 kpc) 70 μm emission is contributed by dust heated by the AGN.

Original languageEnglish
Title of host publicationProceedings of the 12th Scientific Meeting of the Spanish Astronomical Society - Highlights of Spanish Astrophysics IX, SEA 2016
EditorsS. Arribas, A. Alonso-Herrero, F. Figueras, C. Hernandez-Monteagudo, A. Sanchez-Lavega, S. Perez-Hoyos
PublisherSEA
ISBN (Electronic)9788461789313
Publication statusPublished - 2016
Externally publishedYes
Event12th Scientific Meeting of the Spanish Astronomical Society - Highlights of Spanish Astrophysics IX, SEA 2016 - Bilbao, Spain
Duration: 2016 Jul 182016 Jul 22

Publication series

NameProceedings of the 12th Scientific Meeting of the Spanish Astronomical Society - Highlights of Spanish Astrophysics IX, SEA 2016

Conference

Conference12th Scientific Meeting of the Spanish Astronomical Society - Highlights of Spanish Astrophysics IX, SEA 2016
CountrySpain
CityBilbao
Period16/7/1816/7/22

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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