Quick Search:

uzh logo
Browse by:

Zurich Open Repository and Archive

Maintenance: Tuesday, 5.7.2016, 07:00-08:00

Maintenance work on ZORA and JDB on Tuesday, 5th July, 07h00-08h00. During this time there will be a brief unavailability for about 1 hour. Please be patient.

Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-41694

Lokas, E L; Kazantzidis, S; Majewski, S R; Law, D R; Mayer, L; Frinchaboy, P M (2010). The inner structure and kinematics of the Sagittarius dwarf galaxy as a product of tidal stirring. Astrophysical Journal, 725(2):1516-1527.

Accepted Version
PDF (Accepted manuscript, Version 2)
View at publisher
Accepted Version
PDF (Accepted manuscript, Version 1)


The tidal stirring model envisions the formation of dwarf spheroidal (dSph) galaxies in the Local Group and similar environments via the tidal interaction of disky dwarf systems with a larger host galaxy like the Milky Way. These progenitor disks are embedded in extended dark halos and during the evolution both components suffer strong mass loss. In addition, the disks undergo the morphological transformation into spheroids and the transition from ordered to random motion of their stars. Using collisionless N-body simulations, we construct a model for the nearby and highly elongated Sagittarius (Sgr) dSph galaxy within the framework of the tidal stirring scenario. Constrained by the present orbit of the dwarf, which is fairly well known, the model suggests that in order to produce the majority of tidal debris observed as the Sgr stream, but not yet transform the core of the dwarf into a spherical shape, Sgr must have just passed the second pericenter of its current orbit around the Milky Way. In the model, the stellar component of Sgr is still very elongated after the second pericenter and morphologically intermediate between the strong bar formed at the first pericenter and the almost spherical shape existing after the third pericenter. This is thus the first model of the evolution of the Sgr dwarf that accounts for its observed very elliptical shape. At the present time, there is very little intrinsic rotation left and the velocity gradient detected along the major axis is almost entirely of tidal origin. We model the recently measured velocity dispersion profile for Sgr assuming that mass traces light and estimate its current total mass within 5 kpc to be 5.2 × 108 M sun. To have this mass at present, the model requires that the initial virial mass of Sgr must have been as high as 1.6 × 1010 M sun, comparable to that of the Large Magellanic Cloud, which may serve as a suitable analog for the pre-interaction, Sgr progenitor.


25 citations in Web of Science®
25 citations in Scopus®
Google Scholar™



49 downloads since deposited on 02 Mar 2011
10 downloads since 12 months

Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Date:December 2010
Deposited On:02 Mar 2011 08:10
Last Modified:05 Apr 2016 14:33
Publisher:Institute of Physics Publishing
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:10.1088/0004-637X/725/2/1516
Related URLs:http://arxiv.org/abs/1008.3464

Users (please log in): suggest update or correction for this item

Repository Staff Only: item control page