The VMC Survey - XLII. Near-infrared period-luminosity relations for RR Lyrae stars and the structure of the Large Magellanic Cloud
Abstract
We present results from an analysis of ~29 000 RR Lyrae stars located in the Large Magellanic Cloud (LMC). For these objects, near-infrared time-series photometry from the VISTA survey of the Magellanic Clouds system (VMC) and optical data from the Optical Gravitational Lensing Experiment (OGLE) IV survey and the Gaia Data Release 2 catalogue of confirmed RR Lyrae stars were exploited. Using VMC and OGLE IV magnitudes we derived period-luminosity (PL), period-luminosity-metallicity (PLZ), period-Wesenheit (PW), and period-Wesenheit-metallicity (PWZ) relations in all available bands. More that 7000 RR Lyrae were discarded from the analysis because they appear to be overluminous with respect to the PL relations. The $PL_{K_{\mathrm{s}}}$ relation was used to derive individual distance to ${\sim}22\, 000$ RR Lyrae stars, and study the three-dimensional structure of the LMC. The distribution of the LMC RR Lyrae stars is ellipsoidal with the three axis S1 = 6.5 kpc, S2 = 4.6 kpc, and S3 = 3.7 kpc, inclination i = 22 ± 4° relative to the plane of the sky and position angle of the line of nodes θ = 167 ± 7° (measured from north to east). The north-eastern part of the ellipsoid is closer to us and no particular associated substructures are detected and neither any metallicity gradient.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2021
- DOI:
- 10.1093/mnras/stab901
- arXiv:
- arXiv:2103.15492
- Bibcode:
- 2021MNRAS.504....1C
- Keywords:
-
- stars: variables: RR Lyrae;
- galaxies: distances and redshifts;
- Magellanic Clouds;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- accepted for publication in MNRAS