Precession of the sagittarius stream

V. Belokurov, S. E. Koposov, N. W. Evans, J. Peñarrubia, M. J. Irwin, M. C. Smith, G. F. Lewis, M. Gieles, M. I. Wilkinson, G. Gilmore, Edward W Olszewski, M. Niederste-Ostholt

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Using a variety of stellar tracers - blue horizontal branch stars, main-sequence turn-off stars and red giants - we follow the path of the Sagittarius (Sgr) stream across the sky in Sloan Digital Sky Survey data. Our study presents new Sgr debris detections, accurate distances and line-of-sight velocities that together help to shed new light on the puzzle of the Sgr tails. For both the leading and the trailing tails, we trace the points of their maximal extent, or apocentric distances, and find that they lie at RL = 47.8 ± 0.5 kpc and RT = 102.5 ± 2.5 kpc, respectively. The angular difference between the apocentres is 93.°2 ± 3.°5, which is smaller than predicted for logarithmic haloes. Such differential orbital precession can be made consistent with models of the Milky Way in which the dark matter density falls more quickly with radius. However, currently, no existing Sgr disruption simulation can explain the entirety of the observational data. Based on its position and radial velocity, we show that the unusually large globular cluster NGC 2419 can be associated with the Sgr trailing stream. We measure the precession of the orbital plane of the Sgr debris in the Milky Way potential and show that, surprisingly, Sgr debris in the primary (brighter) tails evolves differently from the secondary (fainter) tails, both in the north and the south.

Original languageEnglish (US)
Article numberstt1862
Pages (from-to)116-131
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume437
Issue number1
DOIs
StatePublished - Dec 2013

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precession
debris
horizontal branch stars
blue stars
orbitals
tracer
globular clusters
radial velocity
line of sight
tracers
sky
halos
dark matter
simulation
stars
radii
detection

Keywords

  • Blue stragglers
  • Galaxy: fundamental parameters
  • Galaxy: halo
  • Galaxy: kinematics and dynamics
  • Stars: carbon
  • Stars: horizontal branch

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Belokurov, V., Koposov, S. E., Evans, N. W., Peñarrubia, J., Irwin, M. J., Smith, M. C., ... Niederste-Ostholt, M. (2013). Precession of the sagittarius stream. Monthly Notices of the Royal Astronomical Society, 437(1), 116-131. [stt1862]. https://doi.org/10.1093/mnras/stt1862

Precession of the sagittarius stream. / Belokurov, V.; Koposov, S. E.; Evans, N. W.; Peñarrubia, J.; Irwin, M. J.; Smith, M. C.; Lewis, G. F.; Gieles, M.; Wilkinson, M. I.; Gilmore, G.; Olszewski, Edward W; Niederste-Ostholt, M.

In: Monthly Notices of the Royal Astronomical Society, Vol. 437, No. 1, stt1862, 12.2013, p. 116-131.

Research output: Contribution to journalArticle

Belokurov, V, Koposov, SE, Evans, NW, Peñarrubia, J, Irwin, MJ, Smith, MC, Lewis, GF, Gieles, M, Wilkinson, MI, Gilmore, G, Olszewski, EW & Niederste-Ostholt, M 2013, 'Precession of the sagittarius stream', Monthly Notices of the Royal Astronomical Society, vol. 437, no. 1, stt1862, pp. 116-131. https://doi.org/10.1093/mnras/stt1862
Belokurov V, Koposov SE, Evans NW, Peñarrubia J, Irwin MJ, Smith MC et al. Precession of the sagittarius stream. Monthly Notices of the Royal Astronomical Society. 2013 Dec;437(1):116-131. stt1862. https://doi.org/10.1093/mnras/stt1862
Belokurov, V. ; Koposov, S. E. ; Evans, N. W. ; Peñarrubia, J. ; Irwin, M. J. ; Smith, M. C. ; Lewis, G. F. ; Gieles, M. ; Wilkinson, M. I. ; Gilmore, G. ; Olszewski, Edward W ; Niederste-Ostholt, M. / Precession of the sagittarius stream. In: Monthly Notices of the Royal Astronomical Society. 2013 ; Vol. 437, No. 1. pp. 116-131.
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