Article
Convergence of Small Scale Ly α Structure at High-z under Different Reionization Scenarios
Author/s | Doughty, Caitlin C.
Hennawi, Joseph F. Davies, Frederick B. Lukić, Zarija Oñorbe Bernis, José ![]() ![]() ![]() ![]() ![]() ![]() |
Department | Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear |
Publication Date | 2023 |
Deposit Date | 2024-05-15 |
Published in |
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Abstract | The Ly α forest (LAF) at z > 5 probes the thermal and reionization history of the intergalactic medium (IGM) and the nature of dark matter, but its interpretation requires comparison to cosmological hydrodynamical simulations. ... The Ly α forest (LAF) at z > 5 probes the thermal and reionization history of the intergalactic medium (IGM) and the nature of dark matter, but its interpretation requires comparison to cosmological hydrodynamical simulations. At high-z, convergence of these simulations is more exacting since transmission is dominated by underdense voids that are challenging to resolve. With evidence mounting for a late end to reionization, small structures down to the sub-kpc level may survive to later times than conventionally thought due to the reduced time for pressure smoothing to impact the gas, further tightening simulation resolution requirements. We perform a suite of simulations using the Eulerian cosmological hydrodynamics code Nyx, spanning domain sizes of 1.25 - 10 h-1 Mpc and 5 - 80 h-1 kpc cells, and explore the interaction of these variables with the timing of reionization on the properties of the matter distribution and the simulated LAF at z = 5.5. In observable Ly α power, convergence within 10 per cent is achieved for k < 0.1 s km-1, but larger k shows deviation of up to 20 per cent. While a later reionization retains more small structure in the density field, because of the greater thermal broadening there is little difference in the convergence of LAF power between early (z = 9) and later (z = 6) reionizations. We conclude that at z ∼5.5, resolutions of 10 kpc are necessary for convergence of LAF power at k < 0.1 s km-1, while higher-k modes require higher resolution, and that the timing of reionization does not significantly impact convergence given realistic photoheating. |
Funding agencies | Department of Energy. United States Ministerio de Ciencia Y Tecnología (MCYT). España |
Project ID. | DE-AC02-05CH11231
![]() 17-SC-20-SC ![]() CNS2022-135878 ![]() BEAGAL18/00057 ![]() |
Citation | Doughty, C.C., Hennawi, J.F., Davies, F.B., Lukić, Z. y Oñorbe Bernis, J. (2023). Convergence of Small Scale Ly α Structure at High-z under Different Reionization Scenarios. Monthly Notices of the Royal Astronomical Society, 525 (3), 3790-3805. https://doi.org/10.1093/mnras/stad2549. |
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