Aubert, Dominique, Deparis, Nicolas, Ocvirk, Pierre, Shapiro, Paul R, Iliev, Ilian T, Yepes, Gustavo, Gottlöber, Stefan, Hoffman, Yehuda and Teyssier, Romain (2018) The inhomogeneous reionization times of present-day galaxies. The Astrophysical Journal, 856 (2). pp. 1-6. ISSN 2041-8213
![]() |
PDF (© 2018. The American Astronomical Society. All rights reserved.)
- Published Version
Available under License All Rights Reserved. Download (1MB) |
Abstract
Today's galaxies experienced cosmic reionization at different times in different locations. For the first time, reionization (50% ionized) redshifts, z R , at the location of their progenitors are derived from new, fully coupled radiation-hydrodynamics simulation of galaxy formation and reionization at z > 6, matched to N-body simulation to z = 0. Constrained initial conditions were chosen to form the well-known structures of the local universe, including the Local Group and Virgo, in a (91 Mpc)3 volume large enough to model both global and local reionization. Reionization simulation CoDa I-AMR, by CPU-GPU code EMMA, used (2048)3 particles and (2048)3 initial cells, adaptively refined, while N-body simulation CoDa I-DM2048, by Gadget2, used (2048)3 particles, to find reionization times for all galaxies at z = 0 with masses M(z = 0) ≥ 108 M ⊙. Galaxies with $M(z=0)\gtrsim {10}^{11}\,{M}_{\odot }$ reionized earlier than the universe as a whole, by up to ~500 Myr, with significant scatter. For Milky Way–like galaxies, z R ranged from 8 to 15. Galaxies with $M(z=0)\lesssim {10}^{11}\,{M}_{\odot }$ typically reionized as late or later than globally averaged 50% reionization at $\langle {z}_{R}\rangle =7.8$, in neighborhoods where reionization was completed by external radiation. The spread of reionization times within galaxies was sometimes as large as the galaxy-to-galaxy scatter. The Milky Way and M31 reionized earlier than global reionization but later than typical for their mass, neither dominated by external radiation. Their most-massive progenitors at z > 6 had z R =9.8 (MW) and 11 (M31), while their total masses had z R = 8.2 (both).
Item Type: | Article |
---|---|
Schools and Departments: | School of Mathematical and Physical Sciences > Physics and Astronomy |
Research Centres and Groups: | Astronomy Centre |
Subjects: | Q Science > QB Astronomy |
Depositing User: | Billy Wichaidit |
Date Deposited: | 06 Jun 2018 14:55 |
Last Modified: | 02 Jul 2019 15:32 |
URI: | http://sro.sussex.ac.uk/id/eprint/76363 |
View download statistics for this item
📧 Request an updateProject Name | Sussex Project Number | Funder | Funder Ref |
---|---|---|---|
Astronomy rolling grant | G0278 | STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL | ST/I000976/1 |
Unset | Unset | STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL | ST/F002858/1 |