Interpreting the observed UV continuum slopes of high-redshift galaxies

Wilkins, Stephen M, Bunker, Andrew, Coulton, William, Croft, Rupert, Di Matteo, Tiziana, Khandai, Nishikanta and Feng, Yu (2013) Interpreting the observed UV continuum slopes of high-redshift galaxies. Monthly Notices of the Royal Astronomical Society, 430 (4). pp. 2885-2890. ISSN 0035-8711

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Abstract

The observed UV continuum slope of star-forming galaxies is strongly affected by the presence of dust. Its observation is then a potentially valuable diagnostic of dust attenuation, particularly at high redshift where other diagnostics are currently inaccessible. Interpreting the observed UV continuum slope in the context of dust attenuation is often achieved assuming the empirically calibrated Meurer et al. relation. Implicit in this relation is the assumption of an intrinsic UV continuum slope (β = −2.23). However, results from numerical simulations suggest that the intrinsic UV continuum slopes of high-redshift star-forming galaxies are bluer than this, and moreover vary with redshift. Using values of the intrinsic slope predicted by numerical models of galaxy formation combined with a Calzetti et al. reddening law we infer UV attenuations (A1500) 0.35–0.5 mag (AV: 0.14 − 0.2 mag assuming Calzetti et al. reddening law) greater than simply assuming the Meurer relation. This has significant implications for the inferred amount of dust attenuation at very high (z ≈ 7) redshift given current observational constraints on β, combined with the Meurer relation, suggesting dust attenuation to be virtually zero in all but the most luminous systems.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Stephen Wilkins
Date Deposited: 26 Apr 2013 09:37
Last Modified: 07 Mar 2017 07:23
URI: http://sro.sussex.ac.uk/id/eprint/44494

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