The Milky Way's circular velocity curve and its constraint on the Galactic mass with RR Lyrae stars

Abstract

We present a sample of 1148 ab-type RR Lyrae (RRLab) variables identified from Catalina Surveys Data Release 1, combined with SDSS DR8 and LAMOST DR4 spectral data. We firstly use a large sample of 860 Galactic halo RRLab stars and derive the circular velocity distributions for the stellar halo. With the precise distances and carefully determined radial velocities (the center-of-mass radial velocities) by considering the pulsation of the RRLab stars in our sample, we can obtain a reliable and comparable stellar halo circular velocity curve. We take two different prescriptions for the velocity anisotropy parameter β in the Jeans equation to study the circular velocity curve and mass profile. We test two different solar peculiar motions in our calculation. Our best result with the adopted solar peculiar motion 1 of (U, V, W) = (11.1, 12, 7.2) km/s is that the enclosed mass of the Milky Way within 50 kpc is (3.75 +/- 1.33) *10^11Msun based on β= 0 and the circular velocity 180 +/- 31.92 (km/s) at 50 kpc. This result is consistent with dynamical model results, and it is also comparable to the previous similar works.

20 pages, 8 figures, accepted by ApJ

References in corpus (7)

• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• The RAVE Survey: Constraining the Local Galactic Escape Speed
• The accretion origin of the Milky Way's stellar halo
• On the Shoulders of Giants: Properties of the Stellar Halo and the Milky Way Mass Distribution
• Kinematics of the stellar halo and the mass distribution of the Milky Way using BHB stars
• The Mass Profile of the Galaxy to 80 kpc
• RR Lyrae in XSTPS: The halo density profile in the North Galactic Cap

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• The Milky Way Revealed by Variable Stars I: Sample Selection of RR Lyrae stars, and Evidence for the Merger History
• A Pristine-UNIONS view on the Galaxy: Kinematics of the distant spur feature of the Sagittarius stream traced by Blue Horizontal Branch stars
• Identifications of RR Lyrae stars and Quasars from the simulated data of Mephisto-W Survey
• Kinematics of the Milky way from the statistical analysis of the Gaia Data Release 3