TY - JOUR
T1 - Effects of self-consistent rest-ultraviolet colours in semi-empirical galaxy formation models
AU - Mirocha, Jordan
AU - Mason, Charlotte
AU - Stark, Daniel P.
N1 - Publisher Copyright:
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Connecting the observed rest-ultraviolet (UV) luminosities of high-z galaxies to their intrinsic luminosities (and thus star formation rates, SFRs) requires correcting for the presence of dust. We bypass a common dust-correction approach that uses empirical relationships between infrared (IR) emission and UV colours, and instead augment a semi-empirical model for galaxy formation with a simple-but self-consistent-dust model and use it to jointly fit high-z rest-UV luminosity functions (LFs) and colour-magnitude relations (MUV-β). In doing so, we find that UV colours evolve with redshift (at fixed UV magnitude), as suggested by observations, even in cases without underlying evolution in dust production, destruction, absorption, or geometry. The observed evolution in our model arises due to the reduction in the mean stellar age and rise in specific SFRs with increasing z. The UV extinction, AUV, evolves similarly with redshift, though we find a systematically shallower relation between AUV and MUV than that predicted by IRX-β relationships derived from z ∼3 galaxy samples. Finally, assuming that high 1600-A transmission (≳0.6) is a reliable Ly α emitter (LAE) indicator, modest scatter in the effective dust surface density of galaxies can explain the evolution both in MUV-β and LAE fractions. These predictions are readily testable by deep surveys with the James Webb Space Telescope.
AB - Connecting the observed rest-ultraviolet (UV) luminosities of high-z galaxies to their intrinsic luminosities (and thus star formation rates, SFRs) requires correcting for the presence of dust. We bypass a common dust-correction approach that uses empirical relationships between infrared (IR) emission and UV colours, and instead augment a semi-empirical model for galaxy formation with a simple-but self-consistent-dust model and use it to jointly fit high-z rest-UV luminosity functions (LFs) and colour-magnitude relations (MUV-β). In doing so, we find that UV colours evolve with redshift (at fixed UV magnitude), as suggested by observations, even in cases without underlying evolution in dust production, destruction, absorption, or geometry. The observed evolution in our model arises due to the reduction in the mean stellar age and rise in specific SFRs with increasing z. The UV extinction, AUV, evolves similarly with redshift, though we find a systematically shallower relation between AUV and MUV than that predicted by IRX-β relationships derived from z ∼3 galaxy samples. Finally, assuming that high 1600-A transmission (≳0.6) is a reliable Ly α emitter (LAE) indicator, modest scatter in the effective dust surface density of galaxies can explain the evolution both in MUV-β and LAE fractions. These predictions are readily testable by deep surveys with the James Webb Space Telescope.
KW - dust, extinction
KW - galaxies: Evolution
KW - galaxies: High-redshift
KW - galaxies: ISM
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U2 - 10.1093/mnras/staa2586
DO - 10.1093/mnras/staa2586
M3 - Article
AN - SCOPUS:85096776242
VL - 498
SP - 2645
EP - 2661
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -