Phase spirals induced by the gas warp

Fuente: arXiv
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Main Authors: Wang, Shuyu, Brown, Anthony G. A., Debattista, Victor P., Khachaturyants, Tigran
Format: Preprint
Published: 2026
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_version_ 1866915923748716544
author Wang, Shuyu
Brown, Anthony G. A.
Debattista, Victor P.
Khachaturyants, Tigran
author_facet Wang, Shuyu
Brown, Anthony G. A.
Debattista, Victor P.
Khachaturyants, Tigran
contents The discovery of the phase space spirals in the Solar neighborhood in Gaia Data Release 2 has prompted various attempts to understand their origin. A source of bending waves, which has been neglected as a cause of the phase spiral, is irregular gas inflow along the warp. We aim to study whether perturbations by the gas warp could induce phase spirals. Accounting for this additional formation scenario for phase spirals could improve our current understanding of the perturbation history of the Milky Way disc. We use two N-body + SPH (Smooth Particle Hydrodynamics) simulations of an isolated galaxy to search for, and study, warp-induced phase spirals. We study the emergence and propagation of the detected phase spirals using Fourier decomposition. We detect strong one-armed phase spirals in the warped simulation. These phase spirals are prevalent and persist over ~10 Gyr. The morphology of these phase spirals varies with location and evolves with time. In particular, the emergence rate of the phase spiral evolves with the gas inflow at the outer disc and the bending wave amplitude, indicating that these phase spirals are a record of warp-induced bending waves. We find that these phase spirals can reach amplitudes comparable to those in the Gaia DR3. We only detect weak and stochastically distributed phase spirals in an unwarped control simulation. We conclude that phase spirals can be induced by the irregular gas accretion along the warp. These phase spirals occur globally and are long-lived.
format Preprint
id arxiv_https___arxiv_org_abs_2604_06862
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Phase spirals induced by the gas warp
Wang, Shuyu
Brown, Anthony G. A.
Debattista, Victor P.
Khachaturyants, Tigran
Astrophysics of Galaxies
The discovery of the phase space spirals in the Solar neighborhood in Gaia Data Release 2 has prompted various attempts to understand their origin. A source of bending waves, which has been neglected as a cause of the phase spiral, is irregular gas inflow along the warp. We aim to study whether perturbations by the gas warp could induce phase spirals. Accounting for this additional formation scenario for phase spirals could improve our current understanding of the perturbation history of the Milky Way disc. We use two N-body + SPH (Smooth Particle Hydrodynamics) simulations of an isolated galaxy to search for, and study, warp-induced phase spirals. We study the emergence and propagation of the detected phase spirals using Fourier decomposition. We detect strong one-armed phase spirals in the warped simulation. These phase spirals are prevalent and persist over ~10 Gyr. The morphology of these phase spirals varies with location and evolves with time. In particular, the emergence rate of the phase spiral evolves with the gas inflow at the outer disc and the bending wave amplitude, indicating that these phase spirals are a record of warp-induced bending waves. We find that these phase spirals can reach amplitudes comparable to those in the Gaia DR3. We only detect weak and stochastically distributed phase spirals in an unwarped control simulation. We conclude that phase spirals can be induced by the irregular gas accretion along the warp. These phase spirals occur globally and are long-lived.
title Phase spirals induced by the gas warp
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2604.06862