%0 Generic %1 jia2020temperature %A Jia, Junyi %A Zhu, Weishan %A Gao, Liang %A Feng, Long-Long %D 2020 %K library %T The temperature of IGM at high redshifts: shock heating and high mach problem %U http://arxiv.org/abs/2001.08396 %X The thermal history of cosmic gas in the Dark Ages remains largely unknown. It is important to quantify the impact of relevant physics on the IGM temperature between $z=10$ and $z 30$, in order to interpret recent and oncoming observations, including results reported by EDGES. We revisit the gas heating due to structure formation shocks in this era, using a set of fixed grid cosmological hydrodynamical simulations performed by three different codes. In all our simulations, the cosmic gas is predicted to be in multiphase state since $z>30$. The gas surrounding high density peaks gradually develops a relation more sharp than $T \rho^2/3$, approximately $T \propto \rho^2$, from $z=30$ to $z=11$, might due to shock heating. Meanwhile, the gas in void region tends to have a large local mach number, and their thermal state varies significantly from code to code. In the redshift range $11-20$, the mass fraction of gas shock heated above the CMB temperature in our simulations is larger than previous semi-analytical results by a factor of 2 to 8. At $z=15$, the fraction varies from $19\%$ to $52 \%$ among different codes. Between $z=11$ and $z=20$, the gas temperature $<1/T_K>_M^-1$ is predicted to be $10-20$ K by two codes, much higher than the adiabatic cooling model and some previous works. However, in our simulations performed by RAMSES, $<1/T_K>_M^-1$ is predicted to be even below the temperature required to explain result of the EDGES. Given the fact that different codes give different predictions, currently, it seems a challenge to make solid prediction on the temperature of gas at $z 17$ in simulations.

@misc{jia2020temperature, abstract = {The thermal history of cosmic gas in the Dark Ages remains largely unknown. It is important to quantify the impact of relevant physics on the IGM temperature between $z=10$ and $z \sim 30$, in order to interpret recent and oncoming observations, including results reported by EDGES. We revisit the gas heating due to structure formation shocks in this era, using a set of fixed grid cosmological hydrodynamical simulations performed by three different codes. In all our simulations, the cosmic gas is predicted to be in multiphase state since $z>30$. The gas surrounding high density peaks gradually develops a relation more sharp than $T \propto \rho^{2/3}$, approximately $T \propto \rho^{2}$, from $z=30$ to $z=11$, might due to shock heating. Meanwhile, the gas in void region tends to have a large local mach number, and their thermal state varies significantly from code to code. In the redshift range $11-20$, the mass fraction of gas shock heated above the CMB temperature in our simulations is larger than previous semi-analytical results by a factor of 2 to 8. At $z=15$, the fraction varies from $\sim 19\%$ to $52 \%$ among different codes. Between $z=11$ and $z=20$, the gas temperature $<1/T_{\rm{K}}>_M^{-1}$ is predicted to be $\sim 10-20$ K by two codes, much higher than the adiabatic cooling model and some previous works. However, in our simulations performed by RAMSES, $<1/T_{\rm{K}}>_M^{-1}$ is predicted to be even below the temperature required to explain result of the EDGES. Given the fact that different codes give different predictions, currently, it seems a challenge to make solid prediction on the temperature of gas at $z \sim 17$ in simulations.}, added-at = {2020-01-24T06:05:05.000+0100}, author = {Jia, Junyi and Zhu, Weishan and Gao, Liang and Feng, Long-Long}, biburl = {https://www.bibsonomy.org/bibtex/24abeca0f80fdb5ed1f6cff488824659d/gpkulkarni}, description = {The temperature of IGM at high redshifts: shock heating and high mach problem}, interhash = {ca1e8ec23fcd409392ff92f8d5cbd795}, intrahash = {4abeca0f80fdb5ed1f6cff488824659d}, keywords = {library}, note = {cite arxiv:2001.08396Comment: 18 pages, 9 figures , accepted by Research in Astronomy and Astronphysics}, timestamp = {2020-01-24T06:05:05.000+0100}, title = {The temperature of IGM at high redshifts: shock heating and high mach problem}, url = {http://arxiv.org/abs/2001.08396}, year = 2020 }