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| Paper: |
Numerical Simulations of Hot Halo Gas in Galaxy Mergers |
| Volume: |
419, Galaxy Evolution: Emerging Insights and Future Challenges |
| Page: |
263 |
| Authors: |
Sinha, M.; Holley-Bockelmann, K. |
| Abstract: |
Galaxy merger simulations have explored the behavior of gas within a galactic disk, yet the dynamics of hot gas within the galaxy halo has been neglected. We report on the results of high-resolution hydrodynamic simulations of colliding galaxies with hot halo gas. We find that: (i) A strong shock is produced in the galaxy halos before the first passage, increasing the temperature of the gas by almost an order of magnitude to ∼106.3 K. (ii) The X-ray luminosity of the shock is strongly dependent on the gas fraction. It is ≥1039 erg/s for gas fractions larger than 10%. (iii) The hot diffuse gas in the simulation also produces X-ray luminosities as large as 1042 erg/s, contributing to the total X-ray background in the Universe. (iv) Approximately 10–20% of the initial gas mass is unbound from the galaxies for equal-mass mergers, while 3–5% of the gas mass is released for the 3:1 and 10:1 mergers. This unbound gas ends up far from the galaxy and can be a feasible mechanism for metal enrichment of the WHIM. We use an analytical halo merger tree to estimate the fraction of gas mass lost over the history of the Universe. |
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