A direct calibration of thtae IRX-β relation in Lyman-break Galaxies at z = 3-5
Journal article, 2018

We use a sample of 4209 Lyman-break galaxies (LBGs) at z ≃ 3, 4, and 5 in the UKIRT Infrared Deep Sky Survey Ultra Deep Survey field to investigate the relationship between the observed slope of the stellar continuum emission in the ultraviolet, β, and the thermal dust emission, as quantified via the so-called 'infrared excess' (IRX=LIR/LUV). Through a stacking analysis, we directly measure the 850-μm flux density of LBGs in our deep (0.9 mJy) James Clerk Maxwell Telescope SCUBA-2 850-μm map as well as deep public Herschel/SPIRE 250-, 350-, and 500-μm imaging. We establish functional forms for the IRX-β relation to z ~ 5, confirming that there is no significant redshift evolution of the relation, and that the resulting average IRX-β curve is consistent with a Calzetti-like attenuation law. Comparing our results with recent works in the literature, we confirm that discrepancies in the slope of the IRX-β relation are driven by biases in the methodology used to determine the ultraviolet slopes. Consistent results are found when IRX-β is evaluated by stacking in bins of stellar mass, and we argue that the near-linear IRX-M* relationship is a better proxy for correcting observed ultraviolet luminosities to total star formation rates, provided an accurate handle on M* and also gives clues as to the physical driver of the role of dust-obscured star formation in high-redshift galaxies.

Galaxies: ISM

Galaxies: high-redshift

Galaxies: star formation

Cosmology: observations




M. P. Koprowski

University of Hertfordshire

K. E. K. Coppin

University of Hertfordshire

J.E. Geach

University of Hertfordshire

R. J. McLure

University of Edinburgh

O. Almaini

University of Nottingham

A. Blain

University Of Leicester

M. Bremer

University of Bristol

N. Bourne

University of Edinburgh

S. C. Chapman

Dalhousie University

C. Conselice

University of Nottingham

J. S. Dunlop

University of Edinburgh

D. Farrah

Virginia Polytechnic Institute and State University

W. G. Hartley

University College London (UCL)

A. Karim

University of Bonn

Kirsten Kraiberg Knudsen

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

M. J. Michalowski

Adam Mickiewicz University in Poznań

D. Scott

University of British Columbia (UBC)

C. Simpson

Gemini Observatory North

D. J. B. Smith

University of Hertfordshire

P. van der Werf

Leiden University

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 479 4 4355-4366

Subject Categories

Astronomy, Astrophysics and Cosmology


Geosciences, Multidisciplinary



More information

Latest update