@article{7a693d8f89c74b07a9b9d09dff6ecf8a,
title = "Astraeus - III. The environment and physical properties of reionization sources",
abstract = "In this work, we use the ASTRAEUS (seminumerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in Nbody dArk mattEr simUlationS) framework that couples galaxy formation and reionization in the first billion years. Exploring a number of models for reionization feedback and the escape fraction of ionizing radiation from the galactic environment (fesc), we quantify how the contribution of star-forming galaxies (with halo masses Mh > 108.2 M☉) to reionization depends on the radiative feedback model, fesc, and the environmental overdensity. Our key findings are: (i) for constant fesc models, intermediate-mass galaxies (with halo masses of Mh ≃ 109−11 M☉ and absolute UV magnitudes of MUV ∼ −15 to −20) in intermediate-density regions (with overdensity log10(1 + δ) ∼ 0−0.8 on a 2 comoving Mpc spatial scale) drive reionization; (ii) scenarios where fesc increases with decreasing halo mass shift, the galaxy population driving reionization to lower mass galaxies (Mh ≲ 109.5 M☉) with lower luminosities (MUV ≳ −16) and overdensities [log10(1 + δ) ∼ 0−0.5 on a 2 comoving Mpc spatial scale]; (iii) reionization imprints its topology on the ionizing emissivity of low-mass galaxies (Mh ≲ 109 M☉] through radiative feedback. Low-mass galaxies experience a stronger suppression of star formation by radiative feedback and show lower ionizing emissivities in overdense regions; (iv) a change in fesc with galaxy properties has the largest impact on the sources of reionization and their detectability, with the radiative feedback strength and environmental overdensity playing a sub-dominant role; (v) James Webb Space Telescope-surveys (with a limiting magnitude of MUV = −16) will be able to detect the galaxies providing ∼60−70 per cent (∼10 per cent) of reionization photons at z = 7 for constant fesc models (scenarios where fesc increases with decreasing halo mass).",
keywords = "Dark ages, First stars, Galaxies: high-redshift, Intergalactic medium, Methods: numerical, Reionization",
author = "Anne Hutter and Pratika Dayal and Laurent Legrand and Stefan Gottl{\"o}ber and Gustavo Yepes",
note = "Funding Information: The authors thank the anonymous referee for their comments. All the authors acknowledge support from the European Research Council's starting grant ERC StG-717001 ('DELPHI'). PD acknowledges support from the NWO grant 016.VIDI.189.162 ('ODIN') and the European Commission's and University of Groningen's CO-FUND Rosalind Franklin program. GY acknowledges financial support from MICIU/FEDER under project grant PGC2018-094975-C21. The authors wish to thank Peter Behroozi for creating and providing the ROCKSTAR merger trees of the VSMDPL and ESMDPL simulations, and V. Springel for allowing us to use the L-GADGET2 code to run the different Multidark simulation boxes, including the VSMDPL and ESMDPL used in this work. The VSMDPL and ESMDPL simulations have been performed at LRZ Munich within the project pr87yi. The CosmoSim database (www.cosmosim.org) provides access to the simulation and the Rockstar data. The data base is a service by the Leibniz Institute for Astrophysics Potsdam (AIP). This research made use of MATPLOTLIB, a PYTHON library for publication quality graphics (Hunter 2007); and the PYTHON library NUMPY (Oliphant 2006). Funding Information: The authors thank the anonymous referee for their comments. All the authors acknowledge support from the European Research Council{\textquoteright}s starting grant ERC StG-717001 ({\textquoteleft}DELPHI{\textquoteright}). PD acknowledges support from the NWO grant 016.VIDI.189.162 ({\textquoteleft}ODIN{\textquoteright}) and the European Commission{\textquoteright}s and University of Groningen{\textquoteright}s CO-FUND Rosalind Franklin program. GY acknowledges financial support from MICIU/FEDER under project grant PGC2018-094975-C21. The authors wish to thank Peter Behroozi for creating and providing the ROCKSTAR merger trees of the VSMDPL and ESMDPL simulations, and V. Springel for allowing us to use the L-GADGET2 code to run the different Multidark simulation boxes, including the VSMDPL and ESMDPL used in this work. The VSMDPL and ESMDPL simulations have been performed at LRZ Munich within the project pr87yi. The CosmoSim database (www.cosmosim.org) provides access to the Publisher Copyright: {\textcopyright} The Author(s) 2021. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/).",
year = "2021",
month = sep,
doi = "10.1093/mnras/stab877",
language = "English",
volume = "506",
pages = "215--228",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "1",
}