The IRX-beta relation of high-redshift galaxies
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The IRX-beta relation of high-redshift galaxies. / Liang, Lichen; Feldmann, Robert; Hayward, Christopher C.; Narayanan, Desika; Catmabacak, Onur; Keres, Dusan; Faucher-Giguere, Claude-Andre; Hopkins, Philip F.
In: Monthly Notices of the Royal Astronomical Society, Vol. 502, No. 3, 01.04.2021, p. 3210-3241.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The IRX-beta relation of high-redshift galaxies
AU - Liang, Lichen
AU - Feldmann, Robert
AU - Hayward, Christopher C.
AU - Narayanan, Desika
AU - Catmabacak, Onur
AU - Keres, Dusan
AU - Faucher-Giguere, Claude-Andre
AU - Hopkins, Philip F.
PY - 2021/4/1
Y1 - 2021/4/1
N2 - The relation between infrared excess (IRX) and UV spectral slope (beta(UV)) is an empirical probe of dust properties of galaxies. The shape, scatter, and redshift evolution of this relation are not well understood, however, leading to uncertainties in estimating the dust content and star formation rates (SFRs) of galaxies at high redshift. In this study, we explore the nature and properties of the IRX-beta(UV) relation with a sample of z = 2-6 galaxies (M-* approximate to 10(9)-10(12) M-circle dot) extracted from high-resolution cosmological simulations (MassiveFIRE) of the Feedback in Realistic Environments (FIRE) project. The galaxies in our sample show an IRX-beta(UV) relation that is in good agreement with the observed relation in nearby galaxies. IRX is tightly coupled to the UV optical depth, and is mainly determined by the dust-to-star geometry instead of total dust mass, while beta(UV) is set both by stellar properties, UV optical depth, and the dust extinction law. Overall, much of the scatter in the IRX-beta(UV) relation of our sample is found to be driven by variations of the intrinsic UV spectral slope. We further assess how the IRX-beta(UV) relation depends on viewing direction, dust-to-metal ratio, birth-cloud structures, and the dust extinction law and we present a simple model that encapsulates most of the found dependencies. Consequently, we argue that the reported 'deficit' of the infrared/sub-millimetre bright objects at z greater than or similar to 5 does not necessarily imply a non-standard dust extinction law at those epochs.
AB - The relation between infrared excess (IRX) and UV spectral slope (beta(UV)) is an empirical probe of dust properties of galaxies. The shape, scatter, and redshift evolution of this relation are not well understood, however, leading to uncertainties in estimating the dust content and star formation rates (SFRs) of galaxies at high redshift. In this study, we explore the nature and properties of the IRX-beta(UV) relation with a sample of z = 2-6 galaxies (M-* approximate to 10(9)-10(12) M-circle dot) extracted from high-resolution cosmological simulations (MassiveFIRE) of the Feedback in Realistic Environments (FIRE) project. The galaxies in our sample show an IRX-beta(UV) relation that is in good agreement with the observed relation in nearby galaxies. IRX is tightly coupled to the UV optical depth, and is mainly determined by the dust-to-star geometry instead of total dust mass, while beta(UV) is set both by stellar properties, UV optical depth, and the dust extinction law. Overall, much of the scatter in the IRX-beta(UV) relation of our sample is found to be driven by variations of the intrinsic UV spectral slope. We further assess how the IRX-beta(UV) relation depends on viewing direction, dust-to-metal ratio, birth-cloud structures, and the dust extinction law and we present a simple model that encapsulates most of the found dependencies. Consequently, we argue that the reported 'deficit' of the infrared/sub-millimetre bright objects at z greater than or similar to 5 does not necessarily imply a non-standard dust extinction law at those epochs.
KW - dust
KW - extinction
KW - galaxies: evolution
KW - galaxies: high-redshift
KW - galaxies: ISM
KW - infrared: galaxies
KW - STAR-FORMING GALAXIES
KW - DUST RADIATIVE-TRANSFER
KW - FORMATION RATE DENSITY
KW - ULTRA DEEP FIELD
KW - SIMILAR-TO 6
KW - ALMA SPECTROSCOPIC SURVEY
KW - LARGE-MAGELLANIC-CLOUD
KW - LYMAN-BREAK GALAXIES
KW - UV-CONTINUUM SLOPE
KW - HIGH-RESOLUTION
U2 - 10.1093/mnras/stab096
DO - 10.1093/mnras/stab096
M3 - Journal article
VL - 502
SP - 3210
EP - 3241
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 3
ER -
ID: 270618909