The multiple corrugations in the Galactic disk derived from the LAMOST and Gaia survey data

¹ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, PR China
² Shandong Key Laboratory of Space Environment and Exploration Technology, Institute of Space Sciences, School of Space Science and Technology, Shandong University, Weihai 264209, PR China
³ School of Astronomy and Space Science, Nanjing University, Nanjing 210093, PR China
⁴ Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, PR China
⁵ School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, PR China
⁶ School of Physics and Optoelectronic Engineering, Hainan University, Haikou 570228, PR China

^★ Corresponding authors: This email address is being protected from spambots. You need JavaScript enabled to view it. ; This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 15 December 2025
Accepted: 26 March 2026

Abstract

Context. Large spectroscopic and astrometric surveys have revealed complex wave-like features in the Milky Way disk, suggesting that its kinematic and chemical structures are shaped by time-dependent perturbations. Recent studies have reported oscillatory patterns in the R_g–V_ϕ − V_R space, hinting at a possible structural transition in the outer disk.

Aims. We aim to characterise the transition between the inner and outer Galactic thin disk and to investigate whether radial corrugations can provide a plausible physical interpretation of the observed features.

Methods. We analysed two large stellar samples from LAMOST DR8 and Gaia DR3, combining spatial, kinematic, and chemical diagnostics. A simplified corrugation model – consisting of two radial waves propagating in opposite directions – was constructed and fitted to the observed V_R pattern. We further validated the model using N-body simulations.

Results. Both LAMOST and Gaia samples reproduce the previously reported wave-like pattern in the R_g–V_ϕ − V_R plane. We identify a clear transition between the inner and outer disks via the variations in rotational velocity and metallicities. The corrugation model naturally reproduces the periodic variation of V_R with galactocentric radius, and the superposition of the inward- and outward-propagating modes gives rise to a comparable oscillatory pattern in both observations and simulations.

Conclusions. Our modelling suggests that radial corrugations can provide a plausible interpretation of the observed kinematic signatures. The results highlight the complex, multi-perturber nature of the Galactic disk and motivate further investigation with upcoming surveys.