The evolution of the UV-to-mm extragalactic background light: evidence for a top-heavy initial mass function?

William I. Cowley, Cedric G. Lacey, Carlton M. Baugh, Shaun Cole, Carlos S. Frenk, Claudia del P. Lagos

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)
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Abstract

We present predictions for the UV-to-mm extragalactic background light (EBL) from a recent version of the GALFORM semi-analytical model of galaxy formation which invokes a top-heavy stellar initial mass function (IMF) for galaxies undergoing dynamically triggered bursts of star formation. We combine GALFORM with the GRASIL radiative transfer code for computing fully self-consistent TJV-to-mm spectral energy distributions for each simulated galaxy, accounting for the absorption and re-emission of stellar radiation by interstellar dust. The predicted EBL is in near-perfect agreement with recent observations over the whole UV-to-mm spectrum, as is the evolution of the cosmic spectral energy distribution over the redshift range for which observations are available (z less than or similar to 1). We show that approximately 90 per cent of the EDI, is produced at z <2 although this shifts to higher redshifts for sub-mm wavelengths. We assess whether the top-heavy IMF in starbursts is necessary in order to reproduce the EDI, at the same time as other key observables, and find that variant models with a universal solar-neighbourhood IMF display poorer agreement with EDI. observations over the whole UV-to-mm spectrum and fail to match the counts of galaxies in the sub-mm.

Original languageEnglish
Pages (from-to)3082-3101
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume487
Issue number3
DOIs
Publication statusPublished - 11 Aug 2019

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