The Pisces Plume and the Magellanic wake

Belokurov, Vasily; Deason, Alis J; Erkal, Denis; Koposov, Sergey E; Carballo-Bello, Julio A; Smith, Martin C; Jethwa, Prashin; Navarrete, Camila

Abstract

Using RR Lyrae stars in the Gaia Data Release 2 and Pan-STARRS1 we study the properties of the Pisces overdensity, a diffuse substructure in the outer halo of the Milky Way. We show that along the line of sight, Pisces appears as a broad and long plume of stars stretching from 40 to 110 kpc with a steep distance gradient. On the sky Pisces’s elongated shape is aligned with the Magellanic Stream. Using follow-up VLT FORS2 spectroscopy, we have measured the velocity distribution of the Pisces candidate member stars and have shown it to be as broad as that of the Galactic halo but offset to negative velocities. Using a suite of numerical simulations, we demonstrate that the structure has many properties in common with the predicted behaviour of the Magellanic wake, i.e. the Galactic halo overdensity induced by the infall of the Magellanic Clouds.

Citation

Belokurov, V., Deason, A. J., Erkal, D., Koposov, S. E., Carballo-Bello, J. A., Smith, M. C., Jethwa, P., & Navarrete, C. (2019). The Pisces Plume and the Magellanic wake. Monthly Notices of the Royal Astronomical Society: Letters, 488(1), L47-L52. https://doi.org/10.1093/mnrasl/slz101

• Journal Article Type: Article
• Acceptance Date: Jun 21, 2019
• Online Publication Date: Jun 27, 2019
• Publication Date: Sep 30, 2019
• Deposit Date: Sep 13, 2019
• Publicly Available Date: Sep 13, 2019
• Journal: Monthly Notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 488
• Issue: 1
• Pages: L47-L52
• DOI: https://doi.org/10.1093/mnrasl/slz101
• Public URL: https://durham-repository.worktribe.com/output/1287229