dc.contributor.author Bauer, A dc.contributor.author Springel, V dc.contributor.author Vogelsberger, M dc.contributor.author Genel, S dc.contributor.author Torrey, P dc.contributor.author Sijacki, Debora dc.contributor.author Nelson, D dc.contributor.author Hernquist, L dc.date.accessioned 2018-10-10T10:44:28Z dc.date.available 2018-10-10T10:44:28Z dc.date.issued 2015-11-11 dc.identifier.issn 0035-8711 dc.identifier.uri https://www.repository.cam.ac.uk/handle/1810/283512 dc.description.abstract Hydrodynamical simulations of galaxy formation such as the Illustris simulations have progressed to a state where they approximately reproduce the observed stellar mass function from high to low redshift. This in principle allows self-consistent models of reionization that exploit the accurate representation of the diffuse gas distribution together with the realistic growth of galaxies provided by these simulations, within a representative cosmological volume. In this work, we apply and compare two radiative transfer algorithms implemented in a GPU-accelerated code to the $106.5\,{\rm Mpc}$ wide volume of Illustris in postprocessing in order to investigate the reionization transition predicted by this model. We find that the first generation of galaxies formed by Illustris is just about able to reionize the universe by redshift $z\sim 7$, provided quite optimistic assumptions about the escape fraction and the resolution limitations are made. Our most optimistic model finds an optical depth of $\tau\simeq 0.065$, which is in very good agreement with recent Planck 2015 determinations. Furthermore, we show that moment-based approaches for radiative transfer with the M1 closure give broadly consistent results with our angular-resolved radiative transfer scheme. In our favoured fiducial model, 20\% of the hydrogen is reionized by redshift $z=9.20$, and this rapidly climbs to 80\% by redshift $z=6.92$. It then takes until $z=6.24$ before 99\% of the hydrogen is ionized. On average, reionization proceeds `inside-out' in our models, with a size distribution of reionized bubbles that progressively features regions of ever larger size while the abundance of small bubbles stays fairly constant. dc.publisher Oxford University Press (OUP) dc.title Hydrogen reionization in the illustris universe dc.type Article prism.endingPage 3610 prism.issueIdentifier 4 prism.publicationDate 2015 prism.publicationName Monthly Notices of the Royal Astronomical Society prism.startingPage 3593 prism.volume 453 dc.identifier.doi 10.17863/CAM.30875 rioxxterms.versionofrecord 10.1093/mnras/stv1893 rioxxterms.licenseref.uri http://www.rioxx.net/licenses/all-rights-reserved rioxxterms.licenseref.startdate 2015-11-11 dc.contributor.orcid Sijacki, Debora [0000-0002-3459-0438] dc.identifier.eissn 1365-2966 dc.publisher.url http://dx.doi.org/10.1093/mnras/stv1893 rioxxterms.type Journal Article/Review pubs.funder-project-id Science and Technology Facilities Council (ST/L000725/1) cam.issuedOnline 2015-09-09 rioxxterms.freetoread.startdate 2016-01-01
﻿