MHD Simulation in Galactic Center Region with Radiative Cooling and Heating

Fuente: arXiv
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Main Authors: Kakiuchi, Kensuke, Suzuki, Takeru. K., Inutsuka, Shu-ichiro, Inoue, Tsuyoshi, Shimoda, Jiro
Format: Preprint
Published: 2023
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author Kakiuchi, Kensuke
Suzuki, Takeru. K.
Inutsuka, Shu-ichiro
Inoue, Tsuyoshi
Shimoda, Jiro
author_facet Kakiuchi, Kensuke
Suzuki, Takeru. K.
Inutsuka, Shu-ichiro
Inoue, Tsuyoshi
Shimoda, Jiro
contents We investigate the role of magnetic field on the gas dynamics in a galactic bulge region by three dimensional simulations with radiative cooling and heating. While high-temperature corona with $T>10^6\ {\rm K}$ is formed in the halo regions, the temperature near the mid-plane is $\lesssim 10^4\ {\rm K}$ following the thermal equilibrium curve determined by the radiative cooling and heating. Although the thermal energy of the interstellar gas is lost by radiative cooling, the saturation level of the magnetic field strength does not significantly depend on the radiative cooling and heating. The magnetic field strength is amplified to $10\ {\rm μG}$ on average, and reaches several hundred ${\rm μG}$ locally. We find the formation of magnetically dominated regions at mid-latitudes in the case with the radiative cooling and heating, which is not seen in the case without radiative effect. The vertical thickness of the mid-latitude regions is $50-150\ {\rm pc}$ at the radial location of $0.4-0.8\ {\rm kpc}$ from the galactic center, which is comparable to the observed vertical distribution of neutral atomic gas. When we take the average of different components of energy density integrated over the galactic bulge region, the magnetic energy is comparable to the thermal energy. We conclude that the magnetic field plays a substantial role in controlling the dynamical and thermal properties of the galactic bulge region.
format Preprint
id arxiv_https___arxiv_org_abs_2306_15761
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle MHD Simulation in Galactic Center Region with Radiative Cooling and Heating
Kakiuchi, Kensuke
Suzuki, Takeru. K.
Inutsuka, Shu-ichiro
Inoue, Tsuyoshi
Shimoda, Jiro
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
We investigate the role of magnetic field on the gas dynamics in a galactic bulge region by three dimensional simulations with radiative cooling and heating. While high-temperature corona with $T>10^6\ {\rm K}$ is formed in the halo regions, the temperature near the mid-plane is $\lesssim 10^4\ {\rm K}$ following the thermal equilibrium curve determined by the radiative cooling and heating. Although the thermal energy of the interstellar gas is lost by radiative cooling, the saturation level of the magnetic field strength does not significantly depend on the radiative cooling and heating. The magnetic field strength is amplified to $10\ {\rm μG}$ on average, and reaches several hundred ${\rm μG}$ locally. We find the formation of magnetically dominated regions at mid-latitudes in the case with the radiative cooling and heating, which is not seen in the case without radiative effect. The vertical thickness of the mid-latitude regions is $50-150\ {\rm pc}$ at the radial location of $0.4-0.8\ {\rm kpc}$ from the galactic center, which is comparable to the observed vertical distribution of neutral atomic gas. When we take the average of different components of energy density integrated over the galactic bulge region, the magnetic energy is comparable to the thermal energy. We conclude that the magnetic field plays a substantial role in controlling the dynamical and thermal properties of the galactic bulge region.
title MHD Simulation in Galactic Center Region with Radiative Cooling and Heating
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2306.15761