Dynamics of the outer disk and halo of M31

Abstract

view Abstract Citations (30) References (70) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Dynamics of the Outer Disk and Halo of M31 Nolthenius, Richard ; Ford, Holland C. Abstract The authors present observations of 37 planetary nebulae projecting 15 - 30 kpc radius near the major axis on both the southwest and northeast sides of M31. They give velocities for 34 of the nebulae, separate them into disk and halo objects, and analyze them using four published models of M31's warped disk. The (assumed flat) rotation rate of the disk planetaries is about 218±12 km s-1, ≡12 km s-1 below the circular velocity. Simple models are used to infer a Z dispersion, which indicates that the planetaries form a disk of semithickness 1-3 kpc. The total disk population is probably 2700 or more. The rotation rate of the halo planetaries is 92±43 km s-1, in good agreement with the globular cluster system. The total spheroidal planetary nebula population is about 6500±3500, 2-6 times the Milky Way value, and suggests that M31 has a more massive spheroid. Publication: The Astrophysical Journal Pub Date: June 1987 DOI: 10.1086/165256 Bibcode: 1987ApJ...317...62N Keywords: Andromeda Galaxy; Galactic Structure; Halos; Planetary Nebulae; Radial Velocity; Stellar Motions; Disk Galaxies; Globular Clusters; Astrophysics; GALAXIES: INDIVIDUAL MESSIER NUMBER: M31; GALAXIES: INTERNAL MOTIONS; GALAXIES: STRUCTURE; NEBULAE: PLANETARY full text sources ADS | data products SIMBAD (38) NED (3)