Measuring Star Formation Rates in the Milky Way from Hi-GAL 70 $μ$m Observations
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| Formato: | Preprint |
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2025
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| author | Elia, D. Evans II, N. J. Soler, J. D. Strafella, F. Schisano, E. Molinari, S. Giannetti, A. Patra, S. |
| author_facet | Elia, D. Evans II, N. J. Soler, J. D. Strafella, F. Schisano, E. Molinari, S. Giannetti, A. Patra, S. |
| contents | Three methods for computing the total star formation rate of the Milky Way agree well with a reference value of $1.65\pm0.19$ M$_\odot$ yr$^{-1}$. They are then used to determine the radial dependence of the star formation rate and face-on map for the Milky Way. First, the method based on a model of star formation in Hi-GAL-defined dense clumps, adjusted for an increase in the gas-to-dust ratio with Galactocentric radius, predicts $1.65\pm0.61$ M$_\odot$ yr$^{-1}$. Second, the method using the 70 $μ$m emission, commonly used in other galaxies, with a technique to assign distances to the extended emission, predicts $1.42^{+0.63}_{-0.44}$ M$_\odot$ yr$^{-1}$. Finally, a method based on theoretical predictions of star formation efficiency as a function of virial parameter, with masses corrected for metallicity dependence, applied to a catalog of molecular clouds also predicts a value in agreement at $1.47$ M$_\odot$ yr$^{-1}$. The three methods predict the radial variation of the star formation rate, with remarkably good agreement from the CMZ out to about 20 kpc. More differences were seen in face-on maps with a resolution of 0.5 kpc made with the three approaches and in comparisons to the local (within 3 kpc) star formation rate, indicating limitations of the methods when applied to smaller scales. The 70 $μ$m star formation rate follows very closely the surface density of molecular gas, corrected for a metallicity-dependent CO conversion factor. A molecular gas depletion time of 1 Gyr is consistent with the data, as is a molecular Kennicutt-Schmidt relation with a power-law slope of $1.10 \pm 0.06$. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2501_14471 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Measuring Star Formation Rates in the Milky Way from Hi-GAL 70 $μ$m Observations Elia, D. Evans II, N. J. Soler, J. D. Strafella, F. Schisano, E. Molinari, S. Giannetti, A. Patra, S. Astrophysics of Galaxies Three methods for computing the total star formation rate of the Milky Way agree well with a reference value of $1.65\pm0.19$ M$_\odot$ yr$^{-1}$. They are then used to determine the radial dependence of the star formation rate and face-on map for the Milky Way. First, the method based on a model of star formation in Hi-GAL-defined dense clumps, adjusted for an increase in the gas-to-dust ratio with Galactocentric radius, predicts $1.65\pm0.61$ M$_\odot$ yr$^{-1}$. Second, the method using the 70 $μ$m emission, commonly used in other galaxies, with a technique to assign distances to the extended emission, predicts $1.42^{+0.63}_{-0.44}$ M$_\odot$ yr$^{-1}$. Finally, a method based on theoretical predictions of star formation efficiency as a function of virial parameter, with masses corrected for metallicity dependence, applied to a catalog of molecular clouds also predicts a value in agreement at $1.47$ M$_\odot$ yr$^{-1}$. The three methods predict the radial variation of the star formation rate, with remarkably good agreement from the CMZ out to about 20 kpc. More differences were seen in face-on maps with a resolution of 0.5 kpc made with the three approaches and in comparisons to the local (within 3 kpc) star formation rate, indicating limitations of the methods when applied to smaller scales. The 70 $μ$m star formation rate follows very closely the surface density of molecular gas, corrected for a metallicity-dependent CO conversion factor. A molecular gas depletion time of 1 Gyr is consistent with the data, as is a molecular Kennicutt-Schmidt relation with a power-law slope of $1.10 \pm 0.06$. |
| title | Measuring Star Formation Rates in the Milky Way from Hi-GAL 70 $μ$m Observations |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2501.14471 |