Abstract
We present a model of the nearby Sagittarius (Sgr) dwarf galaxy that correctly reproduces its present highly elongated shape. The model is based on an N-body simulation of a dwarf galaxy orbiting the Milky Way on an eccentric, tight orbit. The dwarf galaxy is initially composed of a stellar disk embedded in a dark matter halo. Strong tidal forces acting on the dwarf induce bar instability in the disk at the first pericenter passage. The bar is preserved until after the second pericenter which we identify as corresponding to the present time. The simulated dwarf, when observed from the Sun, shows remarkable similarity to the real distribution of M giant stars in Sgr. According to the model, the Sgr dwarf could not have spent much more than 1.3 Gyr on its present orbit or its stellar component would have already transformed into a perfectly spherical shape.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Kazantzidis, S., Łokas, E.L., Callegari, S., Mayer, L., Moustakas, L.A.: On the efficiency of the tidal stirring mechanism for the origin of dwarf spheroidals: dependence on the orbital and structural parameters of the progenitor disky dwarfs. ApJ 726, 98 (34pp) (2011)
Law, D.R., Johnston, K.V., Majewski, S.R.: A two micron all-sky survey view of the Sagittarius dwarf galaxy. IV. Modeling the Sagittarius tidal tails. ApJ 619, 807–823 (2005)
Łokas, E.L., Kazantzidis, S., Majewski, S.R., Law, D.R., Mayer, L., Frinchaboy, P.M.: The inner structure and kinematics of the Sagittarius dwarf galaxy as a product of tidal stirring. ApJ 725, 1516–1527 (2010)
Majewski, S.R., Skrutskie, M.F., Weinberg, M.D., Ostheimer, J.C.: A two micron all sky survey view of the Sagittarius dwarf galaxy. I. Morphology of the Sagittarius core and tidal arms. ApJ 599, 1082–1115 (2003)
Mayer, L., Governato, F., Colpi, M., Moore, B., Quinn, T., Wadsley, J., Stadel, J., Lake, G.: The metamorphosis of tidally stirred dwarf galaxies. ApJ 559, 754–784 (2001)
Acknowledgements
This research and ELŁ’s participation in JENAM 2010 was partially supported by the Polish Ministry of Science and Higher Education under grant NN203025333.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Łokas, E.L., Kazantzidis, S., Majewski, S.R., Law, D.R., Mayer, L., Frinchaboy, P.M. (2012). The Sagittarius Dwarf Galaxy as a Product of Tidal Stirring. In: Papaderos, P., Recchi, S., Hensler, G. (eds) Dwarf Galaxies: Keys to Galaxy Formation and Evolution. Astrophysics and Space Science Proceedings. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-22018-0_11
Download citation
DOI: https://doi.org/10.1007/978-3-642-22018-0_11
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-22017-3
Online ISBN: 978-3-642-22018-0
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)