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Self-consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations [electronic resource].

Published:
Washington, D.C. : United States. Dept. of Energy. Office of Advanced Scientific Computing Research, 2017.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:
Article numbers 106 : digital, PDF file
Additional Creators:
Lawrence Berkeley National Laboratory, United States. Department of Energy. Office of Advanced Scientific Computing Research, United States. Department of Energy. High Energy Physics Division, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary:
The ultraviolet background (UVB) emitted by quasars and galaxies governs the ionization and thermal state of the intergalactic medium (IGM), regulates the formation of high-redshift galaxies, and is thus a key quantity for modeling cosmic reionization. The vast majority of cosmological hydrodynamical simulations implement the UVB via a set of spatially uniform photoionization and photoheating rates derived from UVB synthesis models. In this paper, we show that simulations using canonical UVB rates reionize and, perhaps more importantly, spuriously heat the IGM, much earlier ($z\sim 15$) than they should. This problem arises because at $z\gt 6$, where observational constraints are nonexistent, the UVB amplitude is far too high. We introduce a new methodology to remedy this issue, and we generate self-consistent photoionization and photoheating rates to model any chosen reionization history. Following this approach, we run a suite of hydrodynamical simulations of different reionization scenarios and explore the impact of the timing of reionization and its concomitant heat injection on the thermal state of the IGM. We present a comprehensive study of the pressure smoothing scale of IGM gas, illustrating its dependence on the details of both hydrogen and helium reionization, and argue that it plays a fundamental role in interpreting Lyα forest statistics and the thermal evolution of the IGM. The premature IGM heating we have uncovered implies that previous work has likely dramatically overestimated the impact of photoionization feedback on galaxy formation, which sets the minimum halo mass able to form stars at high redshifts. Finally, we make our new UVB photoionization and photoheating rates publicly available for use in future simulations.
Report Numbers:
E 1.99:1379770
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Published through SciTech Connect.
03/08/2017.
"ark:/13030/qt1572d9rd"
The Astrophysical Journal (Online) 837 2 ISSN 1538-4357 AM
Jose Oñorbe; Joseph F. Hennawi; Zarija Lukić.
Alexander von Humboldt Foundation (Germany)
Federal Ministry of Education and Research (BMBF) (Germany)
Funding Information:
AC02-05CH11231
View MARC record | catkey: 23495400