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mass sagittarius dwarf galaxy

CHEMISTRY OF THE SAGITTARIUS DWARF GALAXY: A TOP-LIGHT INITIAL MASS FUNCTION, OUTFLOWS, AND THE R-PROCESS Andrew McWilliam1, George Wallerstein2, and Marta Mottini2 1 The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA; andy@obs.carnegiescience.edu A constraint on possible orbits is provided by the measured velocity dispersion of the Sgr dwarf's stars: σ0=11± 0.7 km s−1 (Ibata et al. This possibility seems unlikely, however, because the gravitational field of the Magellanic Clouds is probably too weak to deflect the Sgr dwarf through a significant angle, given the relative velocity (∼300 km s−1) at which the Sgr dwarf would have encountered the Clouds — see the simulations of Ibata & Lewis for support of this view. We present a new N-body model for the tidal disruption of the Sagittarius (Sgr) dwarf that is capable of simultaneously satisfying the majority of angular position, distance, and radial velocity constraints imposed by current wide-field surveys of its dynamically young (lsim3 Gyr) tidal debris streams. The model of Ibata & Lewis is attractive because we know that dark matter contributes significantly to the potentials of dwarf galaxies. This fine tuning would not detract from the plausibility of the model if it arose naturally as the Sgr dwarf's orbit and the density profile were fashioned by Galactic tides and dynamical friction against the Galactic halo. (2009). Columns 3 and 7 to 9 refer to the semi-analytic calculations described below. 1993, Gilmore et al. However, for the intermediate range of galactic environments there is still a lack of data. Orbit (g) shows that the time required to reach 16 kpc from 200 kpc can be decreased by making the Sgr dwarf more compact, even though of a lower mass. Textbook solution for Astronomy 1st Edition Andrew Fraknoi; David Morrison; Sidney C. Wolff Chapter 25 Problem 27E. Also in 1999, Jiang & Binney found that it may have started its infall into the Milky Way at a point more than 200 kpc away if its starting mass was as large as ≈1011M☉. What is still unclear is whether the Sgr dwarf and Magellanic Clouds can between them explain the particular morphology of the Galactic warp. Astronomers Reveal Farthest Stars in Milky Way Were Ripped from Another The most recent acquisition was the Sagittarius dwarf, which joined us 7 billion years ago. Orbits with upper-case labels in column 1 have been followed with N-body simulations in addition to the semi-analytic model. The orbit and mass of the Sagittarius dwarf galaxy. Table 2 summarizes a series of orbits computed using the semi-analytic model. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. 1997). Search for more papers by this author. The size of the eld is 9 8.5 arcmin Fig.1.bThe Sagittarius Dwarf ( eld 2). 4 shows, for the orbits shown in Fig. (SagD I G should not be confused with the Sagittarius Dwarf Elliptical Galaxy, SagD E G, a satellite galaxy of the Milky Way discovered decades later in the same … One of our neighbouring galaxies is dying, and it is the Milky Way’s fault. 1997). Secondly we have used a small number of large N-body simulations to calibrate semi-analytic calculations that include dynamical friction and tidal stripping, and have used the semi-analytic calculations to explore more thoroughly the parameter space associated with the initial Sgr dwarf and its orbit. Specifically, the particle positions are used to evaluate the density on a spherical grid. The final column gives the corresponding velocity dispersion 1 kpc from the Sgr dwarf's centre, calculated from the Jeans equation and the density profile D(tsink)ρ(r, 0) for r

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