Hot gas accretion fuels star formation faster than cold accretion in high redshift galaxies
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866917780712849408 |
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| author | Kocjan, Zuzanna Cadiou, Corentin Agertz, Oscar Pontzen, Andrew |
| author_facet | Kocjan, Zuzanna Cadiou, Corentin Agertz, Oscar Pontzen, Andrew |
| contents | We use high-resolution ($\simeq$ 35pc) hydrodynamical simulations of galaxy formation to investigate the relation between gas accretion and star formation in galaxies hosted by dark matter haloes of mass $10^{12}$ $\mathrm{M_\odot}$ at $z = 2$. At high redshift, cold-accreted gas is expected to be readily available for star formation, while gas accreted in a hot mode is expected to require a longer time to cool down before being able to form stars. Contrary to these expectations, we find that the majority of cold-accreted gas takes several hundred Myr longer to form stars than hot-accreted gas after it reaches the inner circumgalactic medium (CGM). Approximately 10% of the cold-accreted gas flows rapidly through the inner CGM onto the galactic disc. The remaining 90% is trapped in a turbulent accretion region that extends up to $\sim$ 50 per cent of the virial radius, from which it takes several hundred Myr for the gas to be transported to the star-forming disc. In contrast, most hot shock-heated gas avoids this 'slow track', and accretes directly from the CGM onto the disc where stars can form. We find that shock-heating of cold gas after accretion in the inner CGM and supernova-driven outflows contribute to, but do not fully explain, the delay in star formation. These processes combined slow down the delivery of cold-accreted gas to the galactic disc and consequently limit the rate of star formation in Milky Way mass galaxies at $z > 2$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_04961 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Hot gas accretion fuels star formation faster than cold accretion in high redshift galaxies Kocjan, Zuzanna Cadiou, Corentin Agertz, Oscar Pontzen, Andrew Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics We use high-resolution ($\simeq$ 35pc) hydrodynamical simulations of galaxy formation to investigate the relation between gas accretion and star formation in galaxies hosted by dark matter haloes of mass $10^{12}$ $\mathrm{M_\odot}$ at $z = 2$. At high redshift, cold-accreted gas is expected to be readily available for star formation, while gas accreted in a hot mode is expected to require a longer time to cool down before being able to form stars. Contrary to these expectations, we find that the majority of cold-accreted gas takes several hundred Myr longer to form stars than hot-accreted gas after it reaches the inner circumgalactic medium (CGM). Approximately 10% of the cold-accreted gas flows rapidly through the inner CGM onto the galactic disc. The remaining 90% is trapped in a turbulent accretion region that extends up to $\sim$ 50 per cent of the virial radius, from which it takes several hundred Myr for the gas to be transported to the star-forming disc. In contrast, most hot shock-heated gas avoids this 'slow track', and accretes directly from the CGM onto the disc where stars can form. We find that shock-heating of cold gas after accretion in the inner CGM and supernova-driven outflows contribute to, but do not fully explain, the delay in star formation. These processes combined slow down the delivery of cold-accreted gas to the galactic disc and consequently limit the rate of star formation in Milky Way mass galaxies at $z > 2$. |
| title | Hot gas accretion fuels star formation faster than cold accretion in high redshift galaxies |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2311.04961 |