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

doi:10.1093/mnrasl/slz101

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

Authors

Vasily Belokurov

Dr Alis Deason alis.j.deason@durham.ac.uk
Associate Professor

Denis Erkal

Sergey E Koposov

Julio A Carballo-Bello

Martin C Smith

Prashin Jethwa

Camila Navarrete

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., …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

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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters ©: 2019 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.