RR Lyrae star distance scale and kinematics from inner bulge to 50 kpc
1 Sternberg Astronomical Institute, M.V.Lomonosov Moscow State University, Universitetskii pr. 13, Moscow, 119992 Russia
2 Astronomy and Astrophysics Research division, Entoto Observatory and Research Center, P.O. Box 8412, Addis Ababa, Ethiopia
3 Astronomisches Rechen-Institut Zentrum für Astronomie der Universität Heidelberg, Germany
4 South African Astronomical Observatory, P.O. Box 9, Observatory, Cape Town, 7935, South Africa
5 Southern African Large Telescope, P.O. Box 9, Observatory, Cape Town, 7935, South Africa
6 Special Astrophysical Observatory of RAS, Nizhnij Arkhyz, Karachai-Circassia 369167, Russia
Published online: 8 September 2017
We use the currently most complete sample of ∼ 3500 type ab RR Lyraes in our Galaxy with available radial-velocity and [Fe/H] measurements to perform a statisticalparallax analysis for a subsample of ∼ 600 type ab RR Lyraes located within 5 kpc from the Sun to refine the parameters of optical and WISE W1-band period-metallicityluminosity relations and adjust our preliminary distances. The new zero point implies the rescaled estimates for the solar Galactocentric distance (RG = 7.99 ± 0.37 kpc) and the LMC distance modulus (DMLMC = 18.39 ±0.09). We use the kinematic data for the entire sample to explore the dependence of the halo and thick-disk RR Lyrae velocity ellipsoids on Galactocentric distance from the inner bulge out to R ∼ 50 kpc.
© The Authors, published by EDP Sciences, 2017
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