Cullen, F.; McLure, R. J.; Khochfar, S.; Dunlop, J. S.; Dalla Vecchia, C.; Carnall, A. C.; Bourne, N.; Castellano, M.; Cimatti, A.; Cirasuolo, M.; Elbaz, D.; Fynbo, J. P. U.; Garilli, B.; Koekemoer, A.; Marchi, F.; Pentericci, L.; Talia, M.; Zamorani, G.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 476, Issue 3, p.3218-3232
Description
We present the results of a new study of dust attenuation at redshifts 3
< z < 4 based on a sample of 236 star-forming galaxies from the
VANDELS spectroscopic survey. Motivated by results from the First
Billion Years (FiBY) simulation project, we argue that the intrinsic
spectral energy distributions (SEDs) of star-forming galaxies at these
redshifts have a self-similar shape across the mass range 8.2 ≤ log
(M⋆/M⊙) ≤ 10.6 probed by our sample.
Using FiBY data, we construct a set of intrinsic SED templates which
incorporate both detailed star formation and chemical abundance
histories, and a variety of stellar population synthesis (SPS) model
assumptions. With this set of intrinsic SEDs, we present a novel
approach for directly recovering the shape and normalization of the dust
attenuation curve. We find, across all of the intrinsic templates
considered, that the average attenuation curve for star-forming galaxies
at z ≃ 3.5 is similar in shape to the commonly adopted Calzetti
starburst law, with an average total-to-selective attenuation ratio of
RV = 4.18 ± 0.29. In contrast, we find that an average
attenuation curve as steep as the SMC extinction law is strongly
disfavoured. We show that the optical attenuation (AV) versus
stellar mass (M⋆) relation predicted using our method is
consistent with recent ALMA observations of galaxies at 2 < z < 3
in the Hubble Ultra Deep Field (HUDF), as well as empirical
AV - M⋆ relations predicted by a
Calzetti-like law. In fact, our results, combined with other literature
data, suggest that the AV-M⋆ relation does
not evolve over the redshift range 0 < z < 5, at least for
galaxies with log(M⋆/M⊙) ≳ 9.5.
Finally, we present tentative evidence which suggests that the
attenuation curve may become steeper at lower masses
log(M⋆/M⊙) ≲ 9.0.
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