An intuitive 3D map of the Galactic warp’s precession traced by classical Cepheids

Xiaodian Chen*, Shu Wang, Licai Deng, Richard de Grijs, Chao Liu, Hao Tian

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    106 Citations (Scopus)

    Abstract

    The Milky Way’s neutral hydrogen (H i) disk is warped and flared 1,2 . However, a dearth of accurate H i-based distances has thus far prevented the development of an accurate Galactic Disk model. Moreover, the extent to which our Galaxy’s stellar and gas disk morphologies are mutually consistent is also unclear. Classical Cepheids, primary distance indicators with distance accuracies of 3–5% (ref. 3 ), offer a unique opportunity to develop an intuitive and accurate three-dimensional picture. Here, we establish a robust Galactic Disk model based on 1,339 classical Cepheids. We provide strong evidence that the warp’s line of nodes is not oriented in the Galactic Centre–Sun direction. Instead, it subtends a mean angle of 17.5° ± 1° (formal) ± 3° (systematic) and exhibits a leading spiral pattern. Our Galaxy thus follows Briggs’ rule for spiral galaxies 4 , which suggests that the origin of the warp is associated with torques forced by the massive inner disk 5 . The stellar disk traced by Cepheids follows the gas disk in terms of their amplitudes; the stellar disk extends to at least 20 kpc (refs. 6,7 ). This morphology provides a crucial, updated map for studies of the kinematics and archaeology of the Galactic Disk.

    Original languageEnglish
    Pages (from-to)320-325
    Number of pages6
    JournalNature Astronomy
    Volume3
    Issue number4
    Early online dateFeb 2019
    DOIs
    Publication statusPublished - Apr 2019

    Keywords

    • (lcsh)Physics
    • (lcsh)Astrophysics
    • (lcsh)Astronomy
    • Physics, general
    • (lcsh)Cosmology
    • Astronomy, Astrophysics and Cosmology

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