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1999AJ....118.1719J - Astron. J., 118, 1719-1726 (1999/October-0)
Constraining the history of the Sagittarius dwarf galaxy using observations of its tidal debris.
JOHNSTON K.V., MAJEWSKI S.R., SIEGEL M.H., REID I.N. and KUNKEL W.E.
Abstract (from CDS):
We determine debris models with these properties on orbits that are consistent with the currently known positions and velocities of Sgr in Galactic potentials with halo components that have circular velocities vcirc=140-200 km.s–1. In all cases, the orbits oscillate between ∼12 and ∼40 kpc from the Galactic center with radial time periods of 0.55-0.75 Gyr. The best match to the data is obtained in models where Sgr currently has a mass of ∼109 M☉ and has orbited the Galaxy for at least the last 1 Gyr, during which time it has reduced its mass by a factor of 2-3, or luminosity by an amount equivalent to ∼10% of the total luminosity of the Galactic halo. These numbers suggest that Sgr is rapidly disrupting and unlikely to survive beyond a few more pericentric passages. These conclusions are only tentative, because they rely heavily on the less certain measurements of debris properties far from the center of Sgr. However, they demonstrate the immense potential for using debris to determine Sgr's dynamical history in great detail.
Abstract Copyright: ∼
Journal keyword(s): Galaxies: Dwarf - Galaxies: Evolution - Galaxies: Individual: Name: Sagittarius - Galaxies: Interactions - Galaxies: Kinematics and Dynamics - Methods: Analytical
Simbad objects: 5
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