A Comprehensive Model for the Monoceros Tidal Stream
Year: 2004
Type: article
Abstract: In a ACDM universe, the inner regions of massive galaxies like the Milky Way gain a large fraction of their mass through tidal disruption and accretion of a large number of low-mass fragments (e.g., van den Bosch et al. 2004). The fossil records of these merging processes may be observable nowadays in the form of long tidal streams or large-scale stellar substructures around the parent spiral galaxies. Numerical galaxy formation simulations show that dynamical friction brings substructures from outer halo regions to the neighborhood of the parent galaxies' disks. If halos are flattened (oblate) and their axisymmetry plane is that of the disk, orbits of nonpolar satellite galaxies tend to become coplanar and circularize with time (Pen arrubia et al. 2004). In this scenario, the tidal debris of several disrupted satellite galaxies might have contributed to the formation of the stellar disk if they followed nearly circular orbits with a low orbital inclination at late times of their evolution (Navarro 2004 and references therein). The Milky Way is an important laboratory in which the predictions of this cosmological scenario can be tested. In the last decade, large-scale surveys have proved the existence of tidal streams (Sagittarius Ibata et al. 1994 andMonoceros Newberg et al. 2002) in our Galaxy, providing strong observational evidence that disruption of dwarf satellites contributes to the assembly of some components of our Galaxy. These tidal streams offer a unique opportunity to study accretion events in considerable detail using the chemical, kinematic, and spatial distribution of tidal stream's stars, which can be directly compared against predictions of N-body simulations of merging events (e.g., Law et al. 2005).
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3101934231