Abstract
A panoramic survey of M31's outer regions using the Isaac Newton Telescope Wide Field Camera has revealed a substantial and surprising amount of stellar substructure in the halo of this spiral galaxy, some of which can be used to probe the dark matter distribution of the halo. In particular, a giant stellar stream is observed to extend over a radial range of some 120 kpc from the centre of M31. Combining this with radial velocity data, taken with Keck/DEIMOS, allows for numerical modelling of the orbit of the stream and directly measures, for the first time, the mass of a giant galaxy's halo out to large galactocentric radius. The dynamical mass of M31 within the volume probed by the stream is 7.5 - 15 x 10(11) M-circle dot, and a halo of mass <5 x 10(11) M-circle dot is ruled out at the 99% confidence level. A complimentary study of M31's satellite galaxies reveals that their distribution is extremely assymetric, and that the gross assymetry correlates strongly with the position of the Milky Way. The causes of such a distribution, and the consequences for the usage of the satellites as tracers of the dynamical mass of M31, are discussed.
| Original language | English |
|---|---|
| Title of host publication | Identification of Dark Matter |
| Editors | NJC Spooner, Kudryavtsev |
| Publisher | WORLD SCIENTIFIC PUBL CO PTE LTD |
| Pages | 92-97 |
| Number of pages | 6 |
| ISBN (Print) | 981-256-344-X |
| Publication status | Published - 2005 |
| Event | 5th International Workshop on the Identification of Dark Matter - Edinburgh Duration: 6 Sep 2004 → 10 Sep 2004 |
Conference
| Conference | 5th International Workshop on the Identification of Dark Matter |
|---|---|
| City | Edinburgh |
| Period | 6/09/04 → 10/09/04 |
Keywords
- RED GIANT BRANCH
- MILKY-WAY
- HALO
- ANDROMEDA
- STREAM
- MODELS
- MASS
- TIP