Journal
ASTRONOMICAL JOURNAL
Volume 127, Issue 2, Pages 914-924Publisher
IOP PUBLISHING LTD
DOI: 10.1086/381486
Keywords
Galaxy : halo; Galaxy : kinematics and dynamics; stars : horizontal-branch
Categories
Ask authors/readers for more resources
We carry out a maximum-likelihood kinematic analysis of a sample of 1170 blue horizontal-branch (BHB) stars from the Sloan Digital Sky Survey presented by Sirko and coworkers. Monte Carlo simulations and resampling show that the results are robust to distance and velocity errors at least as large as the errors they estimated. The best-fit velocities of the Sun (circular) and halo (rotational) are 245.9+/-13.5 km s(-1) and 23.8+/-20.1 km s(-1) but are strongly covariant, so that v(circle dot)-v(halo)=222.1+/-7.7 km s(-1). If one adopts standard values for the local standard of rest and solar motion, then the halo scarcely rotates. The velocity ellipsoid inferred for our sample is much more isotropic [(sigma(r), sigma(theta), sigma(phi))=(101.4+/-2.8; 97.7+/-16.4; 107.4+/-16.6) km s(-1)] than that of halo stars in the solar neighborhood, in agreement with a recent study of the distant halo by Sommer-Larsen and coworkers. The line-of-sight velocity distribution of the entire sample, corrected for the Sun's motion, is accurately Gaussian with a dispersion of 101.6+/-3.0 km s(-1).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available