Mapping the Galactic disk with the LAMOST and Gaia Red clump sample. VI: An evidence for the long lived non-steady warp of non-gravitational scenarios

Abstract

By combining LAMOST DR4 and Gaia DR2 common red clump stars with age and proper motion, we analyze the amplitude evolution of the stellar warp independently of any assumption with a simple model. The greatest height of the warp disk increases with Galactocentric distance in different populations and it is dependent on the age: the younger stellar populations exhibit stronger warp features than the old ones, accompanied with the warp amplitude $\gamma (\mathrm{age})$ decreasing with age and its first derivative $\dot{\gamma }(\mathrm{age})$ is different from zero. The azimuth of line of nodes ${\varphi }_w$ is stable at $-$5 degree without clear time evolution, which perfectly confirms some of previous works. All these self-consistent evidences support that our Galactic warp should most likely be a long lived, but non-steady structure and not a transient one, which is supporting the warp is originated from gas infall onto the disk or other hypotheses that suppose that the warp mainly affects to the gas, and consequently younger populations tracing the gas are stronger than the older ones. In other words, the Galactic warp is induced by the non-gravitational interaction over the disk models.

13 pages, 6 figures. Accepted for publication in The Astrophysical Journal

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Cited by in corpus (11)

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• Exploring the pertubed Milky Way disk and the substructures of the outer disk
• A twisted and precessing Cepheid warp in the outer Milky Way disc
• Warp and flare of the old Galactic disc as traced by the red clump stars
• Age-metallicity dependent stellar kinematics of the Milky Way disc from LAMOST and Gaia
• 3-D kinematics of classical Cepheids according to Gaia, EDR3 catalog
• Parameters of the Galactic Spiral Density Wave from Masers with Parallax Errors Less Than 10%
• Azimuthal Misalignments in Stellar Warp Structure as Dynamical Tracers of Mergers in Milky Way-like Galaxies