The influence of the cloud virial parameter on the initial mass function

Journal Article · 05 December 2024 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stae2692 · OSTI ID:2482582

Mathew, Sajay Sunny ; Federrath, Christoph ; Seta, Amit

ABSTRACT Crucial for star formation is the interplay between gravity and turbulence. The observed cloud virial parameter, $$\alpha _{\mathrm{vir}}$$, 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 $$\alpha _{\mathrm{vir}}$$ may challenge the notion of a universal IMF. To determine the role of $$\alpha _{\mathrm{vir}}$$ on the IMF, we compare the star-particle mass functions obtained in high-resolution magnetohydrodynamical simulations including jet and heating feedback, with $$\alpha _{\mathrm{vir}}=0.0625$$, 0.125, and 0.5. We find that varying $$\alpha _{\mathrm{vir}}$$ from $$\alpha _{\mathrm{vir}}\sim 0.5$$ to $$\alpha _{\mathrm{vir}}< 0.1$$ shifts the peak of the IMF to lower masses by a factor of $$\sim 2$$ and increases the star formation rate by a similar factor. The dependence of the IMF and star formation rate on $$\alpha _{\mathrm{vir}}$$ is non-linear, with the dependence subsiding at $$\alpha _{\mathrm{vir}}< 0.1$$. Our study shows a systematic dependence of the IMF on $$\alpha _{\mathrm{vir}}$$. Yet, it may not be measurable easily in observations, considering the uncertainties, and the relatively weak dependence found in this study.

• Sponsoring Organization: USDOE
• OSTI ID: 2482582
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 536; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English