The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128

Details The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128 The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128

2003-11-10

arxiv.org/abs/astro-ph/0311236v1

Astrophys.J. 602 (2004) 685-704

Astronomy and Astrophysics

Astrophysics

21 pages, 13 figures (figures 3-8 best viewed in color), accepted for publication in the Astrophysical Journal

Scientific paper

10.1086/381160

The halos of elliptical galaxies are faint and difficult to explore, but they contain vital clues to both structure and formation. We present the results of an imaging and spectroscopic survey for planetary nebulae (PNe) in the nearby elliptical NGC 5128. We extend the work of Hui et al.(1995) well into the halo of the galaxy--out to distances of 100 and 50 kpc along the major and minor axes. We now know of 1141 PNe in NGC 5128, 780 of which are confirmed. Of these 780 PNe, 349 are new from this survey, and 148 are at radii beyond 20 kpc. PNe exist at distances up to 80 kpc (~15 r_e), showing that the stellar halo extends to the limit of our data. This study represents by far the largest kinematic study of an elliptical galaxy to date, both in the number of velocity tracers and in radial extent. We confirm the large rotation of the PNe along the major axis, and show that it extends in a disk-like feature into the halo. The rotation curve of the stars flattens at ~100 km/s with V/sigma between 1 and 1.5, and with the velocity dispersion of the PNe falling gradually at larger radii. The two-dimensional velocity field exhibits a zero-velocity contour with a pronounced twist, showing that the galaxy potential is likely triaxial in shape, tending toward prolate. The total dynamical mass of the galaxy within 80 kpc is ~5 x 10^{11} M_sun, with M/L_B ~ 13. This mass-to-light ratio is much lower than what is typically expected for elliptical galaxies.

Affiliated with

Also associated with

No associations

Rating

The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Planetary Nebula System and Dynamics in the Outer Halo of NGC 5128 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-421075