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arXiv · 1706.06605

Simulating galaxies in the reionization era with FIRE-2: galaxy scaling relations, stellar mass functions, and luminosity functions

Xiangcheng Ma·Philip F. Hopkins·Shea Garrison-Kimmel·Claude-André Faucher-Giguère·Eliot Quataert·Michael Boylan-Kolchin·Christopher C. Hayward·Robert Feldmann·Dušan Kereš
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Abstract

We present a suite of cosmological zoom-in simulations at z>5 from the Feedback In Realistic Environments project, spanning a halo mass range M_halo~10^8-10^12 M_sun at z=5. We predict the stellar mass-halo mass relation, stellar mass function, and luminosity function in several bands from z=5-12. The median stellar mass-halo mass relation does not evolve strongly at z=5-12. The faint-end slope of the luminosity function steepens with increasing redshift, as inherited from the halo mass function at these redshifts. Below z~6, the stellar mass function and ultraviolet (UV) luminosity function slightly flatten below M_star~10^4.5 M_sun (fainter than M_1500~-12), owing to the fact that star formation in low-mass halos is suppressed by the ionizing background by the end of reionization. Such flattening does not appear at higher redshifts. We provide redshift-dependent fitting functions for the SFR-M_halo, SFR-M_star, and broad-band magnitude-stellar mass relations. We derive the star formation rate density and stellar mass density at z=5-12 and show that the contribution from very faint galaxies becomes more important at z>8. Furthermore, we find that the decline in the z~6 UV luminosity function brighter than M_1500~-20 is largely due to dust attenuation. Approximately 37% (54%) of the UV luminosity from galaxies brighter than M_1500=-13 (-17) is obscured by dust at z~6. Our results broadly agree with current data and can be tested by future observations.

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Xiangcheng Ma, Philip F. Hopkins, Shea Garrison-Kimmel, Claude-André Faucher-Giguère, Eliot Quataert, Michael Boylan-Kolchin, Christopher C. Hayward, Robert Feldmann, Dušan Kereš. 2017-06-20. Simulating galaxies in the reionization era with FIRE-2: galaxy scaling relations, stellar mass functions, and luminosity functions. https://doi.org/10.1093/mnras%2Fsty1024

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