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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2408.17438 |
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| _version_ | 1866912125845241856 |
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| author | Ledos, Nicolas Ntormousi, Evangelia Takasao, Shinsuke Nagamine, Kentaro |
| author_facet | Ledos, Nicolas Ntormousi, Evangelia Takasao, Shinsuke Nagamine, Kentaro |
| contents | High-redshift ($z\sim2-3$) galaxies accrete circumgalactic gas through cold streams. Recent high-resolution MHD simulations of these streams showed a significant amplification of the intergalactic magnetic field in the shear layer around them. In this work we estimate the magnetisation of high-redshift galaxies that would result purely due to the accretion of already magnetised gas from cold streams. We use the mass inflow rates and saturated magnetic field values from cold stream simulations as input to a simple analytic model that calculates the galactic magnetic field purely from mass accretion. Our model predicts average magnetic field strengths that exceed $\rmμG$ values at $z\sim 2-3$ for inflow rates above $0.1 \, \rm{M_{\odot} yr^{-1}}$. For high inflow rates, our model results are consistent with the recent detection of a strong magnetic field in $z\gtrsim 2.6$ galaxies. Within the assumptions of our simple model, magnetised cold streams emerge as a viable mechanism for seeding a dynamically important galactic magnetic field. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_17438 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Magnetising galaxies with cold inflows Ledos, Nicolas Ntormousi, Evangelia Takasao, Shinsuke Nagamine, Kentaro Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics High-redshift ($z\sim2-3$) galaxies accrete circumgalactic gas through cold streams. Recent high-resolution MHD simulations of these streams showed a significant amplification of the intergalactic magnetic field in the shear layer around them. In this work we estimate the magnetisation of high-redshift galaxies that would result purely due to the accretion of already magnetised gas from cold streams. We use the mass inflow rates and saturated magnetic field values from cold stream simulations as input to a simple analytic model that calculates the galactic magnetic field purely from mass accretion. Our model predicts average magnetic field strengths that exceed $\rmμG$ values at $z\sim 2-3$ for inflow rates above $0.1 \, \rm{M_{\odot} yr^{-1}}$. For high inflow rates, our model results are consistent with the recent detection of a strong magnetic field in $z\gtrsim 2.6$ galaxies. Within the assumptions of our simple model, magnetised cold streams emerge as a viable mechanism for seeding a dynamically important galactic magnetic field. |
| title | Magnetising galaxies with cold inflows |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2408.17438 |