Gespeichert in:
| Hauptverfasser: | , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2026
|
| Schlagworte: | |
| Online-Zugang: | https://arxiv.org/abs/2601.19522 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866915757798981632 |
|---|---|
| author | Li, Jiadong Rix, Hans-Walter Ting, Yuan-Sen Wang, Yu-Ting Mészáros, Szabolcs Medan, Ilija Liu, Chao Yan, Zhiqiang Smith, Peter J. Qiu, Dan Roman-Lopes, Alexandre Green, Gregory M. Horta, Danny Way, Zachary Matsuno, Tadafumi Souza, Stefano Fernández-Trincado, José G. |
| author_facet | Li, Jiadong Rix, Hans-Walter Ting, Yuan-Sen Wang, Yu-Ting Mészáros, Szabolcs Medan, Ilija Liu, Chao Yan, Zhiqiang Smith, Peter J. Qiu, Dan Roman-Lopes, Alexandre Green, Gregory M. Horta, Danny Way, Zachary Matsuno, Tadafumi Souza, Stefano Fernández-Trincado, José G. |
| contents | We present the first determination of the Galactic stellar mass function (MF) for low-mass stars (0.2-0.5 M_sun) at metallicities [Fe/H] < -1. A sample of ~53,000 stars was selected as metal-poor on the basis of both their halo-like orbits and their spectroscopic [Fe/H] from Gaia DR3 BP/RP (XP) spectra. These metallicity estimates for low-mass stars were enabled by calibrating Gaia XP spectra with stellar parameters from SDSS-V. For -1.5 < [Fe/H] < -1, we find that the MF below 0.5 M_sun exhibits a "bottom-heavy" power-law slope of alpha ~ -1.6. We tentatively find that at even lower metallicities, the MF becomes very bottom-light, with a near-flat power-law slope of alpha ~ 0 that implies a severe deficit of low-mass stars. This metallicity-dependent variation is insensitive to the adopted stellar evolution model. These results show that the Galactic low-mass MF is not universal, with variations in the metal-poor regime. A further calibration of XP metallicities in the regime of M < 0.5 M_sun and [Fe/H] < -1.5 will be essential to verify these tentative low-metallicity trends. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_19522 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Variations in the Milky Way's Stellar Mass Function at [Fe/H] < -1 Li, Jiadong Rix, Hans-Walter Ting, Yuan-Sen Wang, Yu-Ting Mészáros, Szabolcs Medan, Ilija Liu, Chao Yan, Zhiqiang Smith, Peter J. Qiu, Dan Roman-Lopes, Alexandre Green, Gregory M. Horta, Danny Way, Zachary Matsuno, Tadafumi Souza, Stefano Fernández-Trincado, José G. Astrophysics of Galaxies We present the first determination of the Galactic stellar mass function (MF) for low-mass stars (0.2-0.5 M_sun) at metallicities [Fe/H] < -1. A sample of ~53,000 stars was selected as metal-poor on the basis of both their halo-like orbits and their spectroscopic [Fe/H] from Gaia DR3 BP/RP (XP) spectra. These metallicity estimates for low-mass stars were enabled by calibrating Gaia XP spectra with stellar parameters from SDSS-V. For -1.5 < [Fe/H] < -1, we find that the MF below 0.5 M_sun exhibits a "bottom-heavy" power-law slope of alpha ~ -1.6. We tentatively find that at even lower metallicities, the MF becomes very bottom-light, with a near-flat power-law slope of alpha ~ 0 that implies a severe deficit of low-mass stars. This metallicity-dependent variation is insensitive to the adopted stellar evolution model. These results show that the Galactic low-mass MF is not universal, with variations in the metal-poor regime. A further calibration of XP metallicities in the regime of M < 0.5 M_sun and [Fe/H] < -1.5 will be essential to verify these tentative low-metallicity trends. |
| title | Variations in the Milky Way's Stellar Mass Function at [Fe/H] < -1 |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2601.19522 |