Using the Planetary Nebula Spectrograph, we have observed and measured the velocities for some 2764 PNe in the disk and halo of the Andromeda galaxy. Preliminary analysis using a basic ring model shows a rotation curve in good agreement with that obtained from HI data out to ~20kpc. Some substructure has also been detected within the velocity field, which can be modeled as the continuation of the tidal-remnant known as the Southern Stream, as it passes through Andromeda's disk.
@article{arxiv.astro-ph/0407331,
title = {Mapping the Stellar Dynamics of M31},
author = {Helen Merrett and M. Merrifield and K. Kuijken and A. Romanowsky and N. Douglas and N. Napolitano and M. Arnaboldi and M. Capaccioli and K. Freeman and O. Gerhard and D. Carter and N. W. Evans and M. Wilkinson and C. Halliday and T. Bridges},
journal= {arXiv preprint arXiv:astro-ph/0407331},
year = {2007}
}
Comments
5 pages, 3 figures, to appear in the proceedings of the ESO-Workshop "Planetary Nebulae beyond the Milky Way", May 19 - 21 (2004), ed. J. R. Walsh, L. Stanghellini, Springer-Verlag