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Lookup NU author(s): Dr Christopher HarrisonORCiD
This is the final published version of an article that has been published in its final definitive form by Oxford University Press, 2018.
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© 2018 The Author(s). We present the star formation rates (SFRs) of a sample of 109 galaxies with X-rayselected active galactic nuclei (AGNs) with moderate to high X-ray luminosities (L2-8 keV = 1042 - 1045 erg s-1), at redshifts 1 < z < 4.7, that were selected to be faint or undetected in the Herschel bands. We combine our deep Atacama large (sub-)millimetre array (ALMA) continuum observations with deblended 8-500 μm photometry from Spitzer and Herschel, and use infrared (IR) spectral energy distribution (SED) fitting and AGN - star formation decomposition methods. The addition of the ALMA photometry results in an order of magnitude more X-ray AGN in our sample with a measured SFR (now 37 %). The remaining 63 % of the sources have SFR upper limits that are typically a factor of 2-10 times lower than the pre-ALMA constraints. With the improved constraints on the IR SEDs, we can now identify a mid-IR (MIR) AGN component in 50%of our sample, compared to only ~1 %previously. We further explore the F870μm/F24μm-redshift plane as a tool for the identification of MIR-emitting AGN, for three different samples representing AGN-dominated, star formationdominated, and composite sources. We demonstrate that the F870μm/F24μm-redshift plane can successfully split between AGN and star formation-dominated sources, and can be used as an AGN identification method.
Author(s): Stanley F, Harrison CM, Alexander DM, Simpson J, Knudsen KK, Mullaney JR, Rosario DJ, Scholtz J
Publication type: Article
Publication status: Published
Journal: Monthly Notices of the Royal Astronomical Society
Print publication date: 01/08/2018
Online publication date: 07/05/2018
Acceptance date: 23/04/2018
Date deposited: 04/02/2020
ISSN (print): 0035-8711
ISSN (electronic): 1365-2966
Publisher: Oxford University Press
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