This paper presents results from photometric and statistical-parallax analysis of a sample of 850 field RR Lyrae (RRL) variables. The photometric and spectroscopic data for our sample of RRLs are obtained from (1) our new spectroscopic observations (for 448 RRLs) carried out with the Southern African Large Telescope (SALT); (2) our photometric observations using the 1.0-m telescope of the South African Astronomical Observatory (SAAO), and (3) literature. These are combined with accurate proper motion data from the second data release of the Gaia mission (DR2). This study primarily determines the velocity distribution of solar neighborhood RRLs, and it also calibrates the zero points of the RRLs’ visual V-band luminosity-metallicity (LZ or MV −[Fe/H]) relation and their period-luminosity-metallicity (PLZ) relations in the WISE W1 − and 2MASS Ks −band. We find the bulk velocity of the halo RRLs relative to the Sun to be (U0, V0, W0)Halo =( − 16 ± 7, −219 ± 7, −6 ± 5) km s−1 in the direction of Galactic center, Galactic rotation, and North Galactic pole, respectively, with velocity-dispersion ellipsoids (σVR, σVφ, σVθ)Halo = (153 ± 7, 106 ± 4, 101 ± 4) km s−1. The corresponding parameters for the disk component are found to be (U0, V0, W0)Disk = ( − 19 ± 5, −46 ± 5, −14 ± 3) km s−1 and (σVR, σVφ, σVθ)Disk =(49 ± 4, 38 ± 4, 25 ± 3) km s−1. The calibrated PLZ in W1 −, Ks −band, and V-band LZ relations are 〈 MW1〉 = −0.824 + 0.124[Fe/H] − 2.381log PF, 〈MKs〉 = −0.804 + 0.101[Fe/H] − 2.33log PF and 〈 MV〉 = 1.041 + 0.232[Fe/H], respectively. The calibrated PLZ and LZ relations are used to estimate the Galactic Center distance and the distance modulus of the Large Magellanic Cloud (LMC), which are found to be 7.99±0.49 kpc and 18.46±0.09 mag, respectively. All our results are in excellent agreement with available literature based on statistical parallax analysis, but are considerably more accurate and precise. Moreover, the zero-points of our calibrated PLZ and LZ relations are quite consistent with current results found by other techniques and yield a LMC distance modulus that is within 0.04 mag of the current most precise estimate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.