J/ApJ/837/106 UV background photoionization & photoheating rates (Onorbe+, 2017)
Self-consistent modeling of reionization in cosmological hydrodynamical
simulations.
Onorbe J., Hennawi J.F., Lukic Z.
<Astrophys. J., 837, 106-106 (2017)>
=2017ApJ...837..106O 2017ApJ...837..106O (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Ultraviolet ; Redshifts
Keywords: early universe; galaxies: evolution; galaxies: formation;
intergalactic medium; large-scale structure of universe;
methods: numerical
Abstract:
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. We show that simulations using canonical UVB
rates reionize and, perhaps more importantly, spuriously heat the IGM,
much earlier (z∼15) than they should. This problem arises because at
z>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. We make our new UVB photoionization and photoheating rates
publicly available for use in future simulations.
Description:
In this paper we have presented results from optically thin
cosmological hydrodynamical simulations using the Nyx code (Almgren+
2013ApJ...765...39A 2013ApJ...765...39A ; Lukic+ 2015MNRAS.446.3697L 2015MNRAS.446.3697L). As commonly done in
multiple intergalactic medium (IGM) and galaxy formation studies, the
UV background is modeled as a uniform and isotropic field that evolves
with redshift. Operationally, the ultraviolet background (UVB)
determines the photoionization and photoheating rates of HI, HeI, and
HeII, which are inputs to the code.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 86 301 Tabulated UV background for late HI reionization
(zreion,HI=6.55), ΔTHI=2e4K;
HeA reionization, ΔTHeII=1.5e4K
table4.dat 86 301 Tabulated UV background for middle HI reionization
(zreion,HI=8.30), ΔTHI=2e4 K;
HeA reionization, ΔTHeII=1.5e4K
table5.dat 86 301 Tabulated UV background for early HI reionization
(zreion,HI=9.70), ΔTHI=2e4K;
HeA reionization, ΔTHeII=1.5e4K
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See also:
J/A+A/318/347 : Absorption lines in QSO 0000-2619 (Savaglio+, 1997)
J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)
J/ApJ/662/72 : Lyman alpha forest of 55 QSOs (Becker+, 2007)
J/ApJS/168/213 : Ionization states and cooling efficiencies (Gnat+, 2007)
J/ApJ/719/1672 : SDSS binary quasars at high redshift. I. (Hennawi+, 2010)
J/MNRAS/404/1295 : Impact of gas pressure on transverse structure
(Peeples+, 2010)
J/ApJ/775/78 : Lyman limit absorption systems in z∼3 QSOs (Fumagalli+, 2013)
J/ApJ/765/137 : HST survey for Lyman limit systems. II. (O'Meara+, 2013)
J/A+A/559/A85 : 1D Lya forest power spectrum (Palanque-Delabrouille+, 2013)
J/ApJ/814/40 : Nearby galaxy filaments with UV obs. (Wakker+, 2015)
J/AJ/150/111 : KODIAQ DR1 (O'Meara+, 2015)
Byte-by-byte Description of file: table[345].dat
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Bytes Format Units Label Explanations
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1- 8 F8.6 [-] log(z+1) [0/1.21] Log redshift plus one
10- 21 E12.6 s-1 GammaHI [0/1.3e-12] H I photoionization rate
23- 34 E12.6 s-1 GammaHeI [0/7.3e-13] He I photoionization rate
36- 47 E12.6 s-1 GammaHeII [0/4.4e-15] He II photoionization rate
49- 60 E12.6 10-7W qdotHI [0/7.8e-24] H I photoheating rate; erg/s
62- 73 E12.6 10-7W qdotHeI [0/9.5e-24] He I photoheating rate; erg/s
75- 86 E12.6 10-7W qdotHeII [0/1.5e-25] He II photoheating rate; erg/s
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-Oct-2017