Dust in Galaxies at z=10−15: Attenuation and Re-emission Predictions from the FirstLight Simulations
Abstract
Dust masses and grain properties in z>10 galaxies remain poorly constrained, as JWST UV attenuation and ALMA dust re-emission are rarely modelled consistently. We perform post-processed 3D dust radiative transfer on 208 snapshots of 99 galaxies at z=10-15 from the FirstLight simulations (M*=106.5-109.5 M⊙), applying twelve dust models per snapshot (2496 runs): four dust-to-metal (DTM) prescriptions and three grain size distributions. Metallicity-dependent DTM models reproduce ALMA dust-mass upper limits at z≳10 and detections at z∼7, as dust-to-stellar mass ratios rise sharply near Z∼0.2 Z⊙, typically at M*≳108.5 M⊙, where grain growth by metal accretion becomes dominant. A constant DTM of 0.4 instead violates more than half of the upper limits. For dust attenuation, SMC-like dust is favored by the observed MUV-βUV relation. The observed UV slopes (βUV≃−2.3) favor small grains (a≲λUV/2π≃0.025 μm) producing steep UV extinction, together with a low abundance of carbonaceous grains or PAHs responsible for the 2175 mathringA bump, consistent with silicate-rich dust. Large-grain stellar dust (a0=0.1 μm) instead yields nearly grey extinction and UV slopes close to the intrinsic value (βUV,0≃−2.6). SMC and MW attenuation curves flatten at AV≳0.3, showing that relatively flat attenuation does not necessarily imply large grains. For dust re-emission, dust peak temperatures reach 60-80 K, exceeding the 40-50 K commonly assumed in ALMA dust-mass estimates. Predicted IR continuum flux increases with UV luminosity; at current ALMA sensitivities (10-20 μJy), detections generally require MUV≲−21.5. Roman wide-field surveys may identify such rare UV-bright galaxies.
Related
- Simulations of Dust Content and Attenuation in z=5−15 Galaxies
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- Unveiling the correlation between the UV 2175 Å dust attenuation bump, PAH emission, and gas-phase metallicity at cosmic noon
- Constraining Effective Viscosity in the Intracluster Medium via the Thermal Sunyaev-Zeldovich Effect -- Predictions from the SLOW Constrained Coma Cluster Simulations
- Big, Dusty Galaxies in Blue Jay: Insights into the Relationship Between Morphology and Dust Attenuation at Cosmic Noon
BibTeX
@misc{nakazato2026dust,
title = {{Dust in Galaxies at $z=10-15$: Attenuation and Re-emission Predictions from the FirstLight Simulations}},
author = {Yurina Nakazato and Akio K. Inoue and Rachel S. Somerville and Daisuke Toyouchi and Kosei Matsumoto and Daniel Ceverino},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.22766},
eprint = {2610.22766},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.22766},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Dust in Galaxies at z=10−15: Attenuation and Re-emission Predictions from the FirstLight Simulations
AU - Yurina Nakazato
AU - Akio K. Inoue
AU - Rachel S. Somerville
AU - Daisuke Toyouchi
AU - Kosei Matsumoto
AU - Daniel Ceverino
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.22766
UR - https://arxiv.org/abs/2610.22766
AB - Dust masses and grain properties in z>10 galaxies remain poorly constrained, as JWST UV attenuation and ALMA dust re-emission are rarely modelled consistently. We perform post-processed 3D dust radiative transfer on 208 snapshots of 99 galaxies at z=10-15 from the FirstLight simulations (M_*=10^6.5-10^9.5 M_⊙), applying twelve dust models per snapshot (2496 runs): four dust-to-metal (DTM) prescriptions and three grain size distributions. Metallicity-dependent DTM models reproduce ALMA dust-mass upper limits at z≳10 and detections at z∼7, as dust-to-stellar mass ratios rise sharply near Z∼0.2 Z_⊙, typically at M_*≳10^8.5 M_⊙, where grain growth by metal accretion becomes dominant. A constant DTM of 0.4 instead violates more than half of the upper limits. For dust attenuation, SMC-like dust is favored by the observed M_UV-β_UV relation. The observed UV slopes (β_UV≃−2.3) favor small grains (a≲λ_UV/2π≃0.025 μm) producing steep UV extinction, together with a low abundance of carbonaceous grains or PAHs responsible for the 2175 mathringA bump, consistent with silicate-rich dust. Large-grain stellar dust (a_0=0.1 μm) instead yields nearly grey extinction and UV slopes close to the intrinsic value (β_UV,0≃−2.6). SMC and MW attenuation curves flatten at A_V≳0.3, showing that relatively flat attenuation does not necessarily imply large grains. For dust re-emission, dust peak temperatures reach 60-80 K, exceeding the 40-50 K commonly assumed in ALMA dust-mass estimates. Predicted IR continuum flux increases with UV luminosity; at current ALMA sensitivities (10-20 μJy), detections generally require M_UV≲−21.5. Roman wide-field surveys may identify such rare UV-bright galaxies.
ER -