The multiplicity of 250- μm Herschel sources in the COSMOS field

Scudder, Jillian M, Oliver, Seb, Hurley, Peter D, Griffin, Matt, Sargent, Mark T, Scott, Douglas, Wang, Lingyu and Wardlow, Julie L (2016) The multiplicity of 250- μm Herschel sources in the COSMOS field. Monthly Notices Of The Royal Astronomical Society, 460 (1). pp. 1119-1130. ISSN 0035-8711

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We investigate the multiplicity of extragalactic sources detected by the Herschel Space Observatory in the COSMOS field. Using 3.6- and 24-μm catalogues, in conjunction with 250-μm data from Herschel, we seek to determine if a significant fraction of Herschel sources are composed of multiple components emitting at 250 μm. We use the XID+ code, using Bayesian inference methods to produce probability distributions of the possible contributions to the observed 250-μm flux for each potential component. The fraction of Herschel flux assigned to the brightest component is highest for sources with total 250-μm fluxes < 45 mJy; however, the flux in the brightest component is still highest in the brightest Herschel sources. The faintest 250-μm sources (30-45 mJy) have the majority of their flux assigned to a single bright component; the second brightest component is typically significantly weaker, and contains the remainder of the 250-μm source flux. At the highest 250-μm fluxes (45-110 mJy), the brightest and second brightest components are assigned roughly equal fluxes, and together are insufficient to reach 100 per cent of the 250-μm source flux. This indicates that additional components are required, beyond the brightest two components, to reproduce the observed flux. 95 per cent of the sources in our sample have a second component that contains more than 10 per cent of the total source flux. Particularly for the brightest Herschel sources, assigning the total flux to a single source may overestimate the flux contributed by around 150 per cent.

Item Type: Article
Keywords: Galaxies: high redshift, Galaxies: statistics, Galaxies: photometry
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Richard Chambers
Date Deposited: 06 May 2016 11:09
Last Modified: 07 Mar 2017 05:14

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Project NameSussex Project NumberFunderFunder Ref
Astrophysics and Cosmology - Sussex Consolidated GrantG1291STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/L000652/1