Exposing sgr tidal debris behind the Galactic disc with M giants selected in WISE∩2MASS

S. E. Koposov*, V. Belokurov, D. B. Zucker, G. F. Lewis, R. A. Ibata, E. W. Olszewski, A. R. Loṕez-Sańchez, E. A. Hyde

*Corresponding author for this work

Research output: Contribution to journalArticle

18 Citations (Scopus)
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Abstract

We show that a combination of infrared photometry from WISE and 2MASS surveys can yield highly pure samples of M giant stars. We take advantage of the new WISEn2MASS M giant selection to trace the Sagittarius (Sgr) trailing tail behind the Galactic disc in the direction of the anticentre. The M giant candidates selected via broad-band photometry are confirmed spectroscopically using AAOmega on the Anglo-Australian Telescope in three fields around the extremity of the Sgr trailing tail in the Southern Galactic hemisphere.We demonstrate that at the Sgr longitude (n-ary logical and) ⊙ = 204°, the line-of-sight velocities of the trailing tail starts to deviate from the track of the Law & Majewski model, confirming the prediction of Belokurov et al. This discovery serves to substantiate the measurement of low differential orbital precession of the Sgr stream which in turn may imply diminished dark matter content within 100 kpc.

Original languageEnglish
Pages (from-to)3110-3117
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume446
Issue number3
DOIs
Publication statusPublished - 21 Jan 2015

Bibliographical note

Copyright 2014 The Authors. First published in Monthly Notices of the Royal Astronomical Society, 446(3), 3110-3117. The original publication is available at http://doi.org/10.1093/mnras/stu2263, published by Oxford University Press on behalf of the Royal Astronomical Society. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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