Clues to growth and disruption of two neighbouring spiral arms of the Milky Way

Fuente: arXiv
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Main Authors: Funakoshi, Natsuki, Matsunaga, Noriyuki, Kawata, Daisuke, Baba, Junichi, Taniguchi, Daisuke, Fujii, Michiko
Format: Preprint
Published: 2024
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author Funakoshi, Natsuki
Matsunaga, Noriyuki
Kawata, Daisuke
Baba, Junichi
Taniguchi, Daisuke
Fujii, Michiko
author_facet Funakoshi, Natsuki
Matsunaga, Noriyuki
Kawata, Daisuke
Baba, Junichi
Taniguchi, Daisuke
Fujii, Michiko
contents Studying the nature of spiral arms is essential for understanding the formation of the intricate disc structure of the Milky Way. The European Space Agency's Gaia mission has provided revolutionary observational data that have uncovered detailed kinematical features of stars in the Milky Way. However, so far the nature of spiral arms continues to remain a mystery. Here we present that the stellar kinematics traced by the classical Cepheids around the Perseus and Outer spiral arms in the Milky Way shows strikingly different kinematical properties from each other: the radial and azimuthal velocities of Cepheids with respect to the Galactic centre show positive and negative correlations in the Perseus and Outer arms, respectively. We also found that the dynamic spiral arms commonly seen in an N-body/hydrodynamics simulation of a Milky Way-like galaxy can naturally explain the observed kinematic trends. Furthermore, a comparison with such a simulation suggests that the Perseus arm is being disrupted while the Outer arm is growing. Our findings suggest that two neighbouring spiral arms in distinct evolutionary phases - growing and disrupting phases - coexist in the Milky Way.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13037
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Clues to growth and disruption of two neighbouring spiral arms of the Milky Way
Funakoshi, Natsuki
Matsunaga, Noriyuki
Kawata, Daisuke
Baba, Junichi
Taniguchi, Daisuke
Fujii, Michiko
Astrophysics of Galaxies
Studying the nature of spiral arms is essential for understanding the formation of the intricate disc structure of the Milky Way. The European Space Agency's Gaia mission has provided revolutionary observational data that have uncovered detailed kinematical features of stars in the Milky Way. However, so far the nature of spiral arms continues to remain a mystery. Here we present that the stellar kinematics traced by the classical Cepheids around the Perseus and Outer spiral arms in the Milky Way shows strikingly different kinematical properties from each other: the radial and azimuthal velocities of Cepheids with respect to the Galactic centre show positive and negative correlations in the Perseus and Outer arms, respectively. We also found that the dynamic spiral arms commonly seen in an N-body/hydrodynamics simulation of a Milky Way-like galaxy can naturally explain the observed kinematic trends. Furthermore, a comparison with such a simulation suggests that the Perseus arm is being disrupted while the Outer arm is growing. Our findings suggest that two neighbouring spiral arms in distinct evolutionary phases - growing and disrupting phases - coexist in the Milky Way.
title Clues to growth and disruption of two neighbouring spiral arms of the Milky Way
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2401.13037