Saeedzadeh, V and Jung, SL and Rennehan, D and Babul, A and Tremmel, M and Quinn, TR and Shao, Z and Sharma, P and Mayer, L and O'sullivan, E and Loubser, SI (2023) Cool and gusty, with a chance of rain: dynamics of multiphase CGM around massive galaxies in the Romulus simulations. In: Monthly Notices of the Royal Astronomical Society, 525 (4). pp. 5677-5701.
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Abstract
Using high-resolution Romulus simulations, we explore the origin and evolution of the circumgalactic medium (CGM) in the region 0.1 ≤ R/R500 ≤ 1 around massive central galaxies in group-scale halos. We find that the CGM is multiphase and highly dynamic. Investigating the dynamics, we identify seven patterns of evolution. We show that these are robust and detected consistently across various conditions. The gas cools via two pathways: (1) filamentary cooling inflows and (2) condensations forming from rapidly cooling density perturbations. In our cosmological simulations, the perturbations are mainly seeded by orbiting substructures. The condensations can form even when the median tcool/tff of the X-ray emitting gas is above 10 or 20. Strong amplitude perturbations can provoke runaway cooling regardless of the state of the background gas. We also find perturbations whose local tcool/tff ratios drop below the threshold but which do not condense. Rather, the ratios fall to some minimum value and then bounce. These are weak perturbations that are temporarily swept up in satellite wakes and carried to larger radii. Their tcool/tff ratios decrease because tff is increasing, not because tcool is decreasing. For structures forming hierarchically, our study highlights the challenge of using a simple threshold argument to infer the CGM's evolution. It also highlights that the median hot gas properties are suboptimal determinants of the CGM's state and dynamics. Realistic CGM models must incorporate the impact of mergers and orbiting satellites, along with the CGM's heating and cooling cycles. © 2023 The Author(s).
| Item Type: | Journal Article |
|---|---|
| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | Clouds; Cooling; Dynamics; Numerical methods; Orbits, Amplitude perturbation; Condition; Density perturbation; Galaxies: clusters: intracluster mediums; Galaxies: groups: generals; Galaxy:halo; High resolution; Method: numerical; Multiphases; X-ray emitting gas, Condensation |
| Department/Centre: | Division of Physical & Mathematical Sciences > Joint Astronomy Programme Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 01 Dec 2023 03:47 |
| Last Modified: | 01 Dec 2023 03:47 |
| URI: | https://eprints.iisc.ac.in/id/eprint/83377 |
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