Age, Chemistry, and Kinematics of the Inner Galaxy Revealed by MUSE

Fuente: arXiv
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Main Authors: Wang, Zixian, Hayden, Michael R., Sharma, Sanjib, Bland-Hawthorn, Joss, Seth, Anil C., Zasowski, Gail
Format: Preprint
Published: 2025
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author Wang, Zixian
Hayden, Michael R.
Sharma, Sanjib
Bland-Hawthorn, Joss
Seth, Anil C.
Zasowski, Gail
author_facet Wang, Zixian
Hayden, Michael R.
Sharma, Sanjib
Bland-Hawthorn, Joss
Seth, Anil C.
Zasowski, Gail
contents The bar/bulge and inner disk are fundamental building blocks of the Milky Way, containing a large fraction of its stellar mass. However, stars in these regions are faint, crowded, and have high extinction, which makes studying their formation and evolution challenging. Using the integral-field spectrograph MUSE with adaptive-optics on the Very Large Telescope, we overcome these limitations and measure accurate ages, chemical abundances, and line-of-sight velocities for 98 main-sequence turn-off and subgiant branch stars with $R_{gc}<3.5$ kpc in Baade's Window. We find that 17% stars have ages younger than 5 Gyr, and the age distribution reveals multiple peaks at 3.1, 4.8, 7.6, and 10.8 Gyr, indicating that star formation in the inner Galaxy occurred in multiple episodes. These stars are predominantly metal-rich but span a broad metallicity range ($-1.2<$[Fe/H]$<+0.6$). The [$α$/Fe]-[Fe/H] distribution shows both $α$-rich and $α$-poor sequences, with most stars being metal-rich and low-[$α$/Fe]. Our results demonstrate that IFUs enable reliable measurements of stellar parameters even in the most crowded regions of the Milky Way, opening a new pathway to study the chemodynamical evolution of the inner Galaxy.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09527
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Age, Chemistry, and Kinematics of the Inner Galaxy Revealed by MUSE
Wang, Zixian
Hayden, Michael R.
Sharma, Sanjib
Bland-Hawthorn, Joss
Seth, Anil C.
Zasowski, Gail
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
The bar/bulge and inner disk are fundamental building blocks of the Milky Way, containing a large fraction of its stellar mass. However, stars in these regions are faint, crowded, and have high extinction, which makes studying their formation and evolution challenging. Using the integral-field spectrograph MUSE with adaptive-optics on the Very Large Telescope, we overcome these limitations and measure accurate ages, chemical abundances, and line-of-sight velocities for 98 main-sequence turn-off and subgiant branch stars with $R_{gc}<3.5$ kpc in Baade's Window. We find that 17% stars have ages younger than 5 Gyr, and the age distribution reveals multiple peaks at 3.1, 4.8, 7.6, and 10.8 Gyr, indicating that star formation in the inner Galaxy occurred in multiple episodes. These stars are predominantly metal-rich but span a broad metallicity range ($-1.2<$[Fe/H]$<+0.6$). The [$α$/Fe]-[Fe/H] distribution shows both $α$-rich and $α$-poor sequences, with most stars being metal-rich and low-[$α$/Fe]. Our results demonstrate that IFUs enable reliable measurements of stellar parameters even in the most crowded regions of the Milky Way, opening a new pathway to study the chemodynamical evolution of the inner Galaxy.
title Age, Chemistry, and Kinematics of the Inner Galaxy Revealed by MUSE
topic Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2512.09527