University of Leicester
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The environments of luminous radio-WISE selected infrared galaxiess

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journal contribution
posted on 2019-08-05, 14:17 authored by JI Penney, AW Blain, D Wylezalek, NA Hatch, C Lonsdale, A Kimball, RJ Assef, JJ Condon, PRM Eisenhardt, SF Jones, M Kim, M Lacy, SI Muldrew, S Petty, A Sajina, A Silva, D Stern, T Diaz-Santos, C-W Tsai, J Wu
We have observed the environments of a population of 33 heavily dust obscured, ultraluminous, high-redshift galaxies, selected using Wide-Field Infrared Survey Explorer (WISE) and NRAO 1.4 GHz VLA Sky Survey atz > 1.3 with the infrared array camera on the Spitzer Space Telescope over 5.12 arcmin × 5.12 arcmin fields. Colour selections are used to quantify any potential overdensities of companion galaxies in these fields. We find no significant excess of galaxies with the standard colour selection for IRAC colours of [3.6] − [4.5] > −0.1 consistent with galaxies at z > 1.3 across the whole fields with respect to wide-area Spitzer comparison fields, but there is a >2σ statistical excess within 0.25 arcmin of the central radioWISE galaxy. Using a colour selection of [3.6] − [4.5] > 0.4, 0.5 magnitudes redder than the standard method of selecting galaxies at z > 1.3, we find a significant overdensity, in which 76 per cent (33 per cent) of the 33 fields have a surface density greater than the 3σ (5σ) level. There is a statistical excess of these redder galaxies within 0.5 arcmin, rising to a central peak ∼2–4 times the average density. This implies that these galaxies are statistically linked to the radio-WISE selected galaxy, indicating similar structures to those traced by red galaxies around radio-loud active galactic nuclei.


The authors wish to thank the staff in the Department of Physics and Astronomy at the Leicester University for their support. This research has used the NASA/IPAC Infrared Science Archive and the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. JP is supported by the Science and Technologies Facilities Council (STFC) studentship. We would also like to thank Omar Almaini and the COSMOS collaboration for making the UDS and COSMOS images and catalogues available. MK was supported by the National Research Foundation of Korea (NRF), grant funded by the Korean government (MSIP) (No. 2017R1C1B2002879). RJA was supported by the Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) grant (NO. 1151408). TD-S acknowledges support from ALMA-CONICYT project 31130005 and FONDECYT regular project 1151239.



Monthly Notices of the Royal Astronomical Society, 2019, 483 (1), pp. 514-528 (15)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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Monthly Notices of the Royal Astronomical Society


Oxford University Press (OUP), Royal Astronomical Society





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