Bernhard, E., Tadhunter, C., Mullaney, J.R. orcid.org/0000-0002-3126-6712 et al. (3 more authors) (2021) The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths. Monthly Notices of the Royal Astronomical Society, 503 (2). pp. 2598-2621. ISSN 0035-8711
Abstract
Measuring the star-forming properties of active galactic nucleus (AGN) hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1–1000 μm) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates and introduce the spectral energy distribution fitting code IRAGNSEP. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local (z < 0.3), low-to-high luminosity AGNs (i.e. Lbol ∼ 1042−46 erg s−1), selected from the 105-month Swift–BAT X-ray survey, which have archival Spitzer–IRS spectra and Herschel photometry. We first built a set of seven galaxy templates using a sample of 55 star-forming galaxies selected via infrared diagnostics. Using these templates, combined with a flexible model for the AGN contribution, we extracted the intrinsic infrared emission of our AGN sample. We further demonstrate that we can reduce the diversity in the intrinsic shapes of AGN spectral energy distributions down to a set of three AGN templates, of which two represent AGN continuum, and one represents silicate emission. Our results indicate that, on average, the contribution of AGNs to the far-infrared (λ ≳ 50 μm) is not as high as suggested by some recent work. We further show that the need for two infrared AGN continuum templates could be related to nuclear obscuration, where one of our templates appears dominated by the emission of the extended polar dust.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | methods: statistical; galaxies: active; galaxies: Seyfert; galaxies: starburst; X-rays: galaxies |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 21 Dec 2021 18:01 |
Last Modified: | 21 Dec 2021 18:01 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/stab419 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:181844 |