Precession of the Sagittarius stream

By V. Belokurov, Sergey E. Koposov, N. Evans II, J. Peñarrubia, M. Irwin, M. Smith, Geraint F. Lewis, M. Gieles, M. Wilkinson, G. Gilmore and 2 more. Monthly notices of the Royal Astronomical Society, 2013

163 citations recorded by the source corpus.

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 R-L = 47.8 +/- 0.5 kpc and R-T = 102.5 +/- 2.5 kpc, respectively. The angular difference between the apocentres is 93.degrees 2 +/- 3.degrees 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.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/036f346690fc9255e123c6d041fcf89c9c2870f8

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Citations in the corpus

`Skinny Milky Way please', says Sagittarius (2014, methodology): “This model provides a natural explanation for the differences in the apocentric distances and the precession angle found for the Sagittarius (Sgr) stream in Belokurov et al. (2014).”
THE CATALINA SURVEYS PERIODIC VARIABLE STAR CATALOG (2014, result): “This was recently confirmed by Belokurov et al. (2014) based on SDSS spectra of M-giants.”
The biggest splash (2019, methodology): “Here, BSgr is the latitude in the coordinate system aligned with the Sgr’s tidal tails, namely a great circle with a pole at (RA, Dec.) = (303.63◦, 59.58◦) (see e.g. Belokurov et al. 2014).”
The local dark matter density (2014, result): “None of the current models fit the very latest data that favour a trailing arm with much larger apocentre than the leading arm (Belokurov et al., 2014).”