|
|||||
|
|
Tracing the star stream through M31 using planetary nebula kinematics |
|
| Authors: | H R Merrett K Kuijken M R Merrifield A J Romanowsky N G Douglas N R Napolitano M Arnaboldi M Capaccioli K C Freeman O Gerhard N W Evans M I Wilkinson C Halliday T J Bridges D Carter |
| Institution: | School of Physics &Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD;Leiden Observatory, PO Box 9513, NL-2300 RA Leiden, the Netherlands;Kapteyn Institute, PO Box 800, NL-9700AV Groningen, the Netherlands;Osservatorio di Capodimonte, Via Moiariello 16, Naples 80131, Italy;Research School of Astronomy and Astrophysics, Australian National University, Canberra ACT 2601, Australia;Astronomisches Institut, Universität Basel, Venusstrasse 7, CH 4102 Binningen, Switzerland;Institute of Astronomy, Madingley Road, Cambridge CB3 OHA;Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy;Anglo-Australian Observatory, Epping, NSW 1710, Australia;Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD |
| Abstract: | We present a possible orbit for the Southern Stream of stars in M31, which connects it to the Northern Spur. Support for this model comes from the dynamics of planetary nebulae (PNe) in the disc of M31: analysis of a new sample of 2611 PNe obtained using the Planetary Nebula Spectrograph reveals ∼20 objects with kinematics inconsistent with the normal components of the galaxy, but which lie at the right positions and velocities to connect the two photometric features via this orbit. The satellite galaxy M32 is coincident with the stream both in position and velocity, adding weight to the hypothesis that the stream comprises its tidal debris. |
| Keywords: | galaxies: individual: M31 galaxies: interactions galaxies: kinematics and dynamics Local Group galaxies: structure |