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arXiv · 1902.10152

Dust attenuation, dust emission, and dust temperature in galaxies at z>=5: a view from the FIRE-2 simulations

Xiangcheng Ma·Christopher C. Hayward·Caitlin M. Casey·Philip F. Hopkins·Eliot Quataert·Lichen Liang·Claude-André Faucher-Giguère·Robert Feldmann·Dušan Kereš
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Abstract

We present a suite of 34 high-resolution cosmological zoom-in simulations consisting of thousands of halos up to M_halo~10^12 M_sun (M_star~10^10.5 M_sun) at z>=5 from the Feedback in Realistic Environments project. We post-process our simulations with a three-dimensional Monte Carlo dust radiative transfer code to study dust extinction, dust emission, and dust temperature within these simulated z>=5 galaxies. Our sample forms a tight correlation between infrared excess (IRX=F_IR/F_UV) and ultraviolet (UV)-continuum slope (beta_UV), despite the patchy, clumpy dust geometry shown in our simulations. We find that the IRX-beta_UV relation is mainly determined by the shape of the extinction curve and is independent of its normalization (set by the dust-to-gas ratio). The bolometric IR luminosity (L_IR) correlates with the intrinsic UV luminosity and the star formation rate (SFR) averaged over the past 10 Myr. We predict that at a given L_IR, the peak wavelength of the dust spectral energy distributions for z>=5 galaxies is smaller by a factor of 2 (due to higher dust temperatures on average) than at z=0. The higher dust temperatures are driven by higher specific SFRs and SFR surface densities with increasing redshift. We derive the galaxy UV luminosity functions (LFs) at z=5-10 from our simulations and confirm that a heavy attenuation is required to reproduce the observed bright-end UVLFs. We also predict the IRLFs and UV luminosity densities at z=5-10. We discuss the implications of our results on current and future observations probing dust attenuation and emission in z>=5 galaxies.

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Xiangcheng Ma, Christopher C. Hayward, Caitlin M. Casey, Philip F. Hopkins, Eliot Quataert, Lichen Liang, Claude-André Faucher-Giguère, Robert Feldmann, Dušan Kereš. 2019-02-26. Dust attenuation, dust emission, and dust temperature in galaxies at z>=5: a view from the FIRE-2 simulations. https://doi.org/10.1093/mnras/stz1324

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