KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS
@article{Kafle2012KINEMATICSOT, title={KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS}, author={Prajwal R. Kafle and Sanjib Sharma and Geraint F. Lewis and Joss Bland-Hawthorn}, journal={The Astrophysical Journal}, year={2012}, volume={761} }
Here, we present a kinematic study of the Galactic halo out to a radius of ∼60 kpc, using 4664 blue horizontal branch stars selected from the SDSS/SEGUE survey to determine key dynamical properties. Using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates (σr, σθ, σϕ) and the anisotropy profile (β). The radial velocity dispersion profile (σr) is measured out to a galactocentric radius of r ∼ 60 kpc, but due to the lack of proper-motion…
Figures and Tables from this paper
130 Citations
Anisotropy of the Milky Way’s Stellar Halo Using K Giants from LAMOST and Gaia
- Physics, GeologyThe Astronomical Journal
- 2019
The anisotropy parameter β characterizes the extent to which orbits in stellar systems are predominantly radial or tangential and is likely to constrain, for the stellar halo of the Milky Way,…
Stellar Velocity Dispersion and Anisotropy of the Milky Way Inner Halo
- Physics, Geology
- 2015
We measure the three components of velocity dispersion, σR, σθ, σϕ, for stars within 6 < R < 30 kpc of the Milky Way using a new radial velocity sample from the MMT telescope. We combine our…
ROTATION CURVE OF THE MILKY WAY OUT TO ∼200 kpc
- Physics
- 2014
The rotation curve (RC) of our Galaxy, the Milky Way, is constructed starting from its very inner regions (few hundred parsecs) out to a large galactocentric distance of ∼200 kpc using kinematical…
Fading Features Found in the Kinematics of the Far-Reaching Milky Way Stellar Halo
- Physics, Geology
- 2015
We test the long-term kinematical stability of a Galactic stellar halo model, due to Kafle et al. (2012), who study the kinematics of approximately 5000 blue horizontal branch stars in the Sloan…
The mass of the Galactic dark matter halo from ∼9000 LAMOST DR5 K giants
- PhysicsResearch in Astronomy and Astrophysics
- 2018
We constrain the mass of the Milky Wayʼs dark matter halo, based on the kinematics of 9627 K giants at Galactocentric distances ranging over 5 kpc < r < 120 kpc drawn from LAMOST DR5. The…
ON THE SHOULDERS OF GIANTS: PROPERTIES OF THE STELLAR HALO AND THE MILKY WAY MASS DISTRIBUTION
- Physics
- 2014
Halo stars orbit within the potential of the Milky Way, and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends…
THE VELOCITY ANISOTROPY OF DISTANT MILKY WAY HALO STARS FROM HUBBLE SPACE TELESCOPE PROPER MOTIONS
- Physics, Geology
- 2013
Based on long baseline (5–7 years) multi-epoch HST/ACS photometry, used previously to measure the proper motion of M31, we present the proper motions (PMs) of 13 main-sequence Milky Way halo stars.…
Co-formation of the disc and the stellar halo
- Physics, Geology
- 2018
Using a large sample of Main Sequence stars with 7-D measurements supplied by Gaia and
SDSS, we study the kinematic properties of the local (within ∼10 kpc from the Sun) stellar
halo. We…
Reliability of the Measured Velocity Anisotropy of the Milky Way Stellar Halo
- Physics
- 2017
Determining the velocity distribution of halo stars is essential for estimating the mass of the Milky Way and for inferring its formation history. Since the stellar halo is a dynamically hot system,…
The Nature of the Milky Way’s Stellar Halo Revealed by the Three Integrals of Motion
- Physics
- 2021
We developed a new selection method of halo stars in the phase-space distribution defined by the three integrals of motion in an axisymmetric Galactic potential (E, L z , I 3), where I 3 is the third…
References
SHOWING 1-10 OF 108 REFERENCES
A Dynamical and Kinematic Model of the Galactic Stellar Halo and Possible Implications for Galaxy Formation Scenarios
- Physics
- 1996
We reanalyze the kinematics and dynamics of the system of blue horizontal-branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of…
VELOCITY DISPERSION PROFILE OF THE MILKY WAY HALO
- Physics
- 2009
We present a spectroscopic sample of 910 distant halo stars from the Hypervelocity Star survey from which we derive the velocity dispersion profile of the Milky Way halo. The sample is a mix of 74%…
The radial velocity dispersion profile of the Galactic halo : constraining the density profile of the dark halo of the Milky Way
- Physics
- 2005
We have compiled a new sample of 240 halo objects with accurate distance and radial velocity measurements, including globular clusters, satellite galaxies, field blue horizontal branch (FHB) stars…
The Milky Way stellar halo out to 40 kpc: squashed, broken but smooth
- Physics, Geology
- 2011
We introduce a new maximum-likelihood method to model the density profile of blue horizontal branch and blue straggler stars and apply it to the Sloan Digital Sky Survey Data Release 8 photometric…
Broken degeneracies: the rotation curve and velocity anisotropy of the Milky Way halo
- Physics
- 2012
We use distant blue horizontal branch stars with Galactocentric distances 16 < r < 48 kpc as kinematic tracers of the Milky Way dark halo. We model the tracer density as an oblate, power law embedded…
The Milky Way’s Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from the Kinematics of ~2400 SDSS Blue Horizontal-Branch Stars
- Physics
- 2008
We derive new constraints on the mass of the Milky Way’s dark matter halo, based on 2401 rigorously selected blue horizontal-branch halo stars from SDSS DR6. This sample enables construction of the…
THE MILKY WAY TOMOGRAPHY WITH SDSS. III. STELLAR KINEMATICS
- Physics
- 2010
We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r < 20 and proper-motion measurements derived from Sloan Digital Sky Survey (SDSS) and POSS astrometry, including…
The Accretion Origin of the Milky Way’s Stellar Halo
- Physics
- 2008
We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using ~4 million color-selected…
MAPPING THE GALACTIC HALO WITH BLUE HORIZONTAL BRANCH STARS FROM THE TWO-DEGREE FIELD QUASAR REDSHIFT SURVEY
- Physics
- 2010
We use 666 blue horizontal branch stars from the 2Qz Redshift Survey to map the Galactic halo in four dimensions (position, distance, and velocity). We find that the halo extends to at least 100 kpc…
STRUCTURE AND KINEMATICS OF THE STELLAR HALOS AND THICK DISKS OF THE MILKY WAY BASED ON CALIBRATION STARS FROM SLOAN DIGITAL SKY SURVEY DR7
- Physics
- 2009
The structure and kinematics of the recognized stellar components of the Milky Way are explored, based on well-determined atmospheric parameters and kinematic quantities for 32360 “calibration stars”…