Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger
Galaxies are surrounded by sizeable gas reservoirs which host a significant amount of metals: the circum-galactic medium (CGM). The CGM acts as a mediator between the galaxy and the extragalactic medium. However, our understanding of how galaxy mergers, a major evolutionary transformation, impact th...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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Oxford University Press (OUP)
2020
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| Online Access: | https://hdl.handle.net/1721.1/128442 |
| _version_ | 1826208005319819264 |
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| author | Hani, Maan H Sparre, Martin Ellison, Sara L Torrey, Paul A. Vogelsberger, Mark |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Hani, Maan H Sparre, Martin Ellison, Sara L Torrey, Paul A. Vogelsberger, Mark |
| author_sort | Hani, Maan H |
| collection | MIT |
| description | Galaxies are surrounded by sizeable gas reservoirs which host a significant amount of metals: the circum-galactic medium (CGM). The CGM acts as a mediator between the galaxy and the extragalactic medium. However, our understanding of how galaxy mergers, a major evolutionary transformation, impact the CGM remains deficient. We present a theoretical study of the effect of galaxy mergers on the CGM. We use hydrodynamical cosmological zoom-in simulations of a major merger selected from the Illustris project such that the z = 0 descendant has a halo mass and stellar mass comparable to the Milky Way. To study the CGM we then re-simulated this system at a 40 times better mass resolution, and included detailed post-processing ionization modelling. Our work demonstrates the effect the merger has on the characteristic size of the CGM, its metallicity, and the predicted covering fraction of various commonly observed gas-phase species, such as HI, CIV, and OVI. We show that merger-induced outflows can increase the CGM metallicity by 0.2-0.3 dex within 0.5 Gyr post-merger. These effects last up to 6 Gyr post-merger. While the merger increases the total metal covering fractions by factors of 2-3, the covering fractions of commonly observed UV ions decrease due to the hard ionizing radiation from the active galactic nucleus, which we model explicitly. Our study of the single simulated major merger presented in this work demonstrates the significant impact that a galaxy interaction can have on the size, metallicity, and observed column densities of the CGM. |
| first_indexed | 2024-09-23T13:58:49Z |
| format | Article |
| id | mit-1721.1/128442 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T13:58:49Z |
| publishDate | 2020 |
| publisher | Oxford University Press (OUP) |
| record_format | dspace |
| spelling | mit-1721.1/1284422022-09-28T17:30:26Z Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger Hani, Maan H Sparre, Martin Ellison, Sara L Torrey, Paul A. Vogelsberger, Mark Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Galaxies are surrounded by sizeable gas reservoirs which host a significant amount of metals: the circum-galactic medium (CGM). The CGM acts as a mediator between the galaxy and the extragalactic medium. However, our understanding of how galaxy mergers, a major evolutionary transformation, impact the CGM remains deficient. We present a theoretical study of the effect of galaxy mergers on the CGM. We use hydrodynamical cosmological zoom-in simulations of a major merger selected from the Illustris project such that the z = 0 descendant has a halo mass and stellar mass comparable to the Milky Way. To study the CGM we then re-simulated this system at a 40 times better mass resolution, and included detailed post-processing ionization modelling. Our work demonstrates the effect the merger has on the characteristic size of the CGM, its metallicity, and the predicted covering fraction of various commonly observed gas-phase species, such as HI, CIV, and OVI. We show that merger-induced outflows can increase the CGM metallicity by 0.2-0.3 dex within 0.5 Gyr post-merger. These effects last up to 6 Gyr post-merger. While the merger increases the total metal covering fractions by factors of 2-3, the covering fractions of commonly observed UV ions decrease due to the hard ionizing radiation from the active galactic nucleus, which we model explicitly. Our study of the single simulated major merger presented in this work demonstrates the significant impact that a galaxy interaction can have on the size, metallicity, and observed column densities of the CGM. NASA (Grants NNX17AG29G and HST-HF2- 51384.001-A) 2020-11-10T21:43:03Z 2020-11-10T21:43:03Z 2017-12 2017-12 2019-06-11T11:53:15Z Article http://purl.org/eprint/type/JournalArticle 0035-8711 1365-2966 https://hdl.handle.net/1721.1/128442 Hani, Maan H. et al. "Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger." Monthly Notices of the Royal Astronomical Society 475, 1 (December 2017): 1160–1176 © 2017 The Author(s) en http://dx.doi.org/10.1093/mnras/stx3252 Monthly Notices of the Royal Astronomical Society Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Oxford University Press (OUP) arXiv |
| spellingShingle | Hani, Maan H Sparre, Martin Ellison, Sara L Torrey, Paul A. Vogelsberger, Mark Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title | Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title_full | Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title_fullStr | Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title_full_unstemmed | Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title_short | Galaxy mergers moulding the circum-galactic medium – I. The impact of a major merger |
| title_sort | galaxy mergers moulding the circum galactic medium i the impact of a major merger |
| url | https://hdl.handle.net/1721.1/128442 |
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