Bibliographic Details
| Title: |
Quantifying radial migration in the Milky Way: Inefficient over short timescales but essential to the very outer disc beyond ~15 kpc |
| Authors: |
Lian, Jianhui, Zasowski, Gail, Hasselquist, Sten, Holtzman, Jon A., Boardman, Nicholas, Cunha, Katia, Fernández-Trincado, José G., Frinchaboy, Peter M., Garcia-Hernandez, D. A., Nitschelm, Christian, Lane, Richard R., Thomas, Daniel, Zhang, Kai |
| Publication Year: |
2022 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
Stellar radial migration plays an important role in reshaping a galaxy's structure and the radial distribution of stellar population properties. In this work, we revisit reported observational evidence for radial migration and quantify its strength using the age--[Fe/H] distribution of stars across the Milky Way with APOGEE data. We find a broken age--[Fe/H] relation in the Galactic disc at $r>6$ kpc, with a more pronounced break at larger radii. To quantify the strength of radial migration, we assume stars born at each radius have a unique age and metallicity, and then decompose the metallicity distribution function (MDF) of mono-age young populations into different Gaussian components that originated from various birth radii at $r_{\rm birth}<13$ kpc. We find that, at ages of 2 and 3 Gyr, roughly half the stars were formed within 1 kpc of their present radius, and very few stars ($<5$%) were formed more than 4 kpc away from their present radius. These results suggest limited short distance radial migration and inefficient long distance migration in the Milky Way during the last 3 Gyr. In the very outer disc beyond 15~kpc, the observed age--[Fe/H] distribution is consistent with the prediction of pure radial migration from smaller radii, suggesting a migration origin of the very outer disc. We also estimate intrinsic metallicity gradients at ages of 2 and 3 Gyr of $-0.061$ dex kpc$^{-1}$ and $-0.063$ dex kpc$^{-1}$, respectively.
Comment: 18 pages, 12 figures, MNRAS in press |
| Document Type: |
Working Paper |
| DOI: |
10.1093/mnras/stac479 |
| Access URL: |
http://arxiv.org/abs/2202.08846 |
| Accession Number: |
edsarx.2202.08846 |
| Database: |
arXiv |
