Tracing the sources of reionization in cosmological radiation hydrodynamics simulations

Harley Katz, Taysun Kimm, Martin G. Haehnelt, Debora Sijacki, Joakim Rosdahl, Jeremy Blaizot

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

We use the photon flux and absorption tracer algorithm presented in Katz et al. to characterize the contribution of haloes of different mass and stars of different age and metallicity to the reionization of the Universe. We employ a suite of cosmological multifrequency radiation hydrodynamics AMR simulations that are carefully calibrated to reproduce a realistic reionization history and galaxy properties at z ≥ 6. In our simulations, haloes with mass 109 M☉ h−1 < M < 1010 M☉ h−1, stars with metallicity 10−3 Z☉ < Z < 10−1.5 Z☉, and stars with age 3 Myr < t < 10 Myr dominate reionization by both mass and volume. We show that the sources that reionize most of the volume of the Universe by z = 6 are not necessarily the same sources that dominate the meta-galactic UV background at the same redshift. We further show that in our simulations, the contribution of each type of source to reionization is not uniform across different gas phases. The IGM, CGM, filaments, ISM, and rarefied supernova heated gas have all been photoionized by different classes of sources. Collisional ionization contributes at both the lowest and highest densities. In the early stages of the formation of individual H II bubbles, reionization proceeds with the formation of concentric shells of gas ionized by different classes of sources, leading to large temperature variations as a function of galacto-centric radius. The temperature structure of individual H II bubbles may thus give insight into the star formation history of the galaxies acting as the first ionizing sources. Our explorative simulations highlight how the complex nature of reionization can be better understood by using our photon tracer algorithm.

Original languageEnglish
Pages (from-to)1029-1041
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume483
Issue number1
DOIs
Publication statusPublished - 2019 Feb 11

Bibliographical note

Funding Information:
This work was performed using the DiRAC/Darwin Supercomputer hosted by the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council.

Funding Information:
This work used the DiRAC Complexity system, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment is funded by BIS National E-Infrastructure capital grant ST/K000373/1 and STFC DiRAC Operations grant ST/K0003259/1.

Funding Information:
We thank the referee for their comments that improved the manuscript. This work made considerable use of the open source analysis software PYNBODY (Pontzen et al. 2013). HK thanks Brasenose College and the support of the Nicholas Kurti Junior Fellowship as well as the Beecroft Fellowship. Support by ERC Advanced Grant 320596 ‘The Emergence of Structure during the Epoch of reionization’ is gratefully acknowledged. DS acknowledges support by STFC and ERC Starting Grant 638707 ‘Black holes and their host galaxies: coevolution across cosmic time’. TK acknowledges support by the Yonsei University Future-leading Research Initiative of 2017 (RMS2-2017-22-0150) and in part by the National Research Foundation of Korea (NRF) grant funded by the Korea government (No. 2018036146). JR and JB acknowledge support from the ORAGE project from the Agence Nationale de la Recherche under grand ANR-14-CE33-0016-03.

Funding Information:
Furthermore, this work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFR DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by the BIS National E-infrastructure capital grant ST/K00042X/1, STFC capital grant ST/K00087X/1, DiRAC operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure.

Funding Information:
We thank the referee for their comments that improved the manuscript. This work made considerable use of the open source analysis software PYNBODY (Pontzen et al. 2013). HK thanks Brasenose College and the support of the Nicholas Kurti Junior Fellowship as well as the Beecroft Fellowship. Support by ERC Advanced Grant 320596 'The Emergence of Structure during the Epoch of reionization' is gratefully acknowledged. DS acknowledges support by STFC and ERC Starting Grant 638707 'Black holes and their host galaxies: coevolution across cosmic time'. TK acknowledges support by the Yonsei University Future-leading Research Initiative of 2017 (RMS2-2017-22-0150) and in part by the National Research Foundation of Korea (NRF) grant funded by the Korea government (No. 2018036146). JR and JB acknowledge support from the ORAGE project from the Agence Nationale de la Recherche under grand ANR-14-CE33-0016-03. This work was performed using the DiRAC/Darwin Supercomputer hosted by the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council. This work used the DiRAC Complexity system, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment is funded by BIS National E-Infrastructure capital grant ST/K000373/1 and STFC DiRAC Operations grant ST/K0003259/1. Furthermore, this work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFR DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by the BIS National E-infrastructure capital grant ST/K00042X/1, STFC capital grant ST/K00087X/1, DiRAC operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure.

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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