A tilted dark halo origin of the Galactic disk warp and flare

2023/09/13 by J. Han, Jiwon Jesse Han, Charlie Conroy +1 · 2 voices · 10 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph.GA

paper · pdf · doi:10.1038/s41550-023-02076-9

openalex publication_date 2023/09/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The outer disk of the Milky Way Galaxy is warped and flared. Several mechanisms have been proposed to explain these phenomena, but none have quantitatively reproduced both features. Recent work has demonstrated that the Galactic stellar halo is tilted with respect to the disk plane, suggesting that at least some component of the dark matter halo may also be tilted. Here we show that a dark halo tilted in the same direction as the stellar halo can induce a warp and flare in the Galactic disk at the same amplitude and orientation as the data. In our model the warp is visible in both the gas and stars of all ages, which is consistent with the breadth of observational tracers of the warp. These results, in combination with data in the stellar halo, provide compelling evidence that our Galaxy is embedded in a tilted dark matter halo. This misalignment of the dark halo and the disk holds clue to the formation history of the Galaxy, and represents the next step in the dynamical modeling of the Galactic potential.

Citations

• The Galaxy in Context: Structural, Kinematic, and Integrated Properties

Cited by

• Mapping the Milky Way with Gaia Bp/Rp Spectra. IV. The Broken and Asymmetric Density Profile of the Stellar Disk Traced by a Large Sample of Red Clumps
• The Milky Way stellar halo is twisted and doubly broken: insights from DESI DR2 Milky Way Survey observation
• Hot accretion onto spiral galaxies: the origin of extended and warped HI discs
• Warped Disk Galaxies. II. From the Cosmic Web to the Galactic Warp
• Azimuthal Misalignments in Stellar Warp Structure as Dynamical Tracers of Mergers in Milky Way-like Galaxies
• The tangled warp of the Milky Way
• Molecular Gas Distribution toward the Inner and Outer Galaxy Revealed by MWISP -- the Galactic Longitude 45°--60°and 120°--130°
• First measurement of the triaxiality of the inner dark matter halo of the Milky Way
• DELVE-ing into the Milky Way's Globular Clusters: Assessing extra-tidal features in NGC 5897, NGC 7492, and testing detectability with deeper photometry
• A Detailed Analysis of the Milky Way Warp Based on Classical Cepheids

Discussions

• Did a tilted dark matter halo produce the Milky Way disc's warp? Han et al suggest it did. I have some thoughts. #arXivoftheweek arxiv.org/abs/2309.07209 1/5 🔭 [bsky, 9 points, 1 comments]
• Here's the paper. arxiv.org/abs/2309.07209 Tilted ~30 degrees they suggest, and probably not quite that thin (but still 'triaxial': different x, y, z lengths). Hmm, I might be underestimating the flar [bsky, 0 points, 1 comments]

Related

• Tilted Dark Halos are Common, Long-Lived, and can Warp Galactic Disks
• Interactions Between Massive Dark Halos And Warped Disks
• A Vertically Orientated Dark Matter Halo Marks a Flip of the Galactic Disk
• The Dynamics of Galactic Warps
• Warped Disk Galaxies. II. From the Cosmic Web to the Galactic Warp