The influence of the cloud virial parameter on the initial mass function
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arXiv
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| Format: | Preprint |
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2024
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| author | Mathew, Sajay Sunny Federrath, Christoph Seta, Amit |
| author_facet | Mathew, Sajay Sunny Federrath, Christoph Seta, Amit |
| contents | Crucial for star formation is the interplay between gravity and turbulence. The observed cloud virial parameter, $α_{\mathrm{vir}}$, which is the ratio of twice the turbulent kinetic energy to the gravitational energy, is found to vary significantly in different environments, where the scatter among individual star-forming clouds can exceed an order of magnitude. Therefore, a strong dependence of the initial mass function (IMF) on $α_{\mathrm{vir}}$ may challenge the notion of a universal IMF. To determine the role of $α_{\mathrm{vir}}$ on the IMF, we compare the star-particle mass functions obtained in high-resolution magnetohydrodynamical simulations including jet and heating feedback, with $α_{\mathrm{vir}}=0.0625$, $0.125$, and $0.5$. We find that varying $α_{\mathrm{vir}}$ from $α_{\mathrm{vir}}\sim0.5$ to $α_{\mathrm{vir}}<0.1$ shifts the peak of the IMF to lower masses by a factor of $\sim2$ and increases the star formation rate by a similar factor. The dependence of the IMF and star formation rate on $α_{\mathrm{vir}}$ is non-linear, with the dependence subsiding at $α_{\mathrm{vir}}<0.1$. Our study shows a systematic dependence of the IMF on $α_{\mathrm{vir}}$. Yet, it may not be measurable easily in observations, considering the uncertainties, and the relatively weak dependence found in this study. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_13137 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The influence of the cloud virial parameter on the initial mass function Mathew, Sajay Sunny Federrath, Christoph Seta, Amit Astrophysics of Galaxies Crucial for star formation is the interplay between gravity and turbulence. The observed cloud virial parameter, $α_{\mathrm{vir}}$, which is the ratio of twice the turbulent kinetic energy to the gravitational energy, is found to vary significantly in different environments, where the scatter among individual star-forming clouds can exceed an order of magnitude. Therefore, a strong dependence of the initial mass function (IMF) on $α_{\mathrm{vir}}$ may challenge the notion of a universal IMF. To determine the role of $α_{\mathrm{vir}}$ on the IMF, we compare the star-particle mass functions obtained in high-resolution magnetohydrodynamical simulations including jet and heating feedback, with $α_{\mathrm{vir}}=0.0625$, $0.125$, and $0.5$. We find that varying $α_{\mathrm{vir}}$ from $α_{\mathrm{vir}}\sim0.5$ to $α_{\mathrm{vir}}<0.1$ shifts the peak of the IMF to lower masses by a factor of $\sim2$ and increases the star formation rate by a similar factor. The dependence of the IMF and star formation rate on $α_{\mathrm{vir}}$ is non-linear, with the dependence subsiding at $α_{\mathrm{vir}}<0.1$. Our study shows a systematic dependence of the IMF on $α_{\mathrm{vir}}$. Yet, it may not be measurable easily in observations, considering the uncertainties, and the relatively weak dependence found in this study. |
| title | The influence of the cloud virial parameter on the initial mass function |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2410.13137 |