Towards Unveiling the Origins of the Milky Way Bulge through Multi-band-Messenger Sky Surveys

Fuente: arXiv
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Main Authors: Wang, Hai-Feng, Han, Xiao, Carraro, Giovanni, Lopez-Corredoira, Martin, Ting, Yuan-Sen, Wang, Guan-Yu
Format: Preprint
Published: 2025
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author Wang, Hai-Feng
Han, Xiao
Carraro, Giovanni
Lopez-Corredoira, Martin
Ting, Yuan-Sen
Wang, Guan-Yu
author_facet Wang, Hai-Feng
Han, Xiao
Carraro, Giovanni
Lopez-Corredoira, Martin
Ting, Yuan-Sen
Wang, Guan-Yu
contents We analyze the structure and chemo-dynamical properties of the Galactic bulge using ab-type RR Lyrae stars (RRabs) from OGLE-IV and giant stars from APOGEE and Gaia. Orbital integration of 1,879 RRab variables reveals three populations: central bulge, inner bulge, and halo/disk contaminants. Inner bulge RRabs display bar-like kinematics, whereas central bulge stars show slower rotation and lower dispersion. APOGEE data for 28,188 stars confirm these kinematic trends and reveal a bimodal chemical distribution, indicating distinct formation pathways. Our results support a pseudo-bulge origin of the inner bulge through disk instability, with the overall morphology better described as boxy rather than X-shaped. Through the integration of multi-messenger, multi-band data, our collaboration aims to provide deeper insights into the physical properties and evolutionary history of the Galactic bulge.
format Preprint
id arxiv_https___arxiv_org_abs_2512_18708
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Towards Unveiling the Origins of the Milky Way Bulge through Multi-band-Messenger Sky Surveys
Wang, Hai-Feng
Han, Xiao
Carraro, Giovanni
Lopez-Corredoira, Martin
Ting, Yuan-Sen
Wang, Guan-Yu
Astrophysics of Galaxies
We analyze the structure and chemo-dynamical properties of the Galactic bulge using ab-type RR Lyrae stars (RRabs) from OGLE-IV and giant stars from APOGEE and Gaia. Orbital integration of 1,879 RRab variables reveals three populations: central bulge, inner bulge, and halo/disk contaminants. Inner bulge RRabs display bar-like kinematics, whereas central bulge stars show slower rotation and lower dispersion. APOGEE data for 28,188 stars confirm these kinematic trends and reveal a bimodal chemical distribution, indicating distinct formation pathways. Our results support a pseudo-bulge origin of the inner bulge through disk instability, with the overall morphology better described as boxy rather than X-shaped. Through the integration of multi-messenger, multi-band data, our collaboration aims to provide deeper insights into the physical properties and evolutionary history of the Galactic bulge.
title Towards Unveiling the Origins of the Milky Way Bulge through Multi-band-Messenger Sky Surveys
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.18708