Properties of RR Lyrae stars in the Inner Regions of the Large Magellanic Cloud

Abstract

We present the radial velocities, metallicities and the K-band magnitudes of 74 RR Lyrae stars in the inner regions of the LMC. The intermediate resolution spectra and infrared images were obtained with FORS1 at the ESO VLT and with the SOFI infrared imager at the ESO NTT. The best 43 RR Lyrae with measured velocities yield an observed velocity dispersion of 61+-7 km/s. We obtain a true LMC RR Lyrae velocity dispersion of 53 km/s, which is higher than the velocity dispersion of any other LMC population previously measured. This is the first empirical evidence for a kinematically hot, metal-poor halo in the LMC as discussed in Minniti et al. (2003). Using Layden's (1994) modification of the Delta S method we measured the metallicity for 23 of our stars. The mean value is [Fe/H] =-1.46+-0.09 dex. The absolute magnitudes M_V and M_K of RR Lyrae stars are linear functions of metallicity. In the V band, our data agree with the Olech et al. (2003) relation, in the K band the slope is flatter. The average apparent V luminosity of 70 RR Lyrae stars is <V> = 19.45+-0.04 and the average K luminosity of 37 RR Lyrae stars is <K>=18.20+-0.06. There is no obvious relation between apparent V magnitude and LogP, while the RR Lyrae K band magnitudes show a well defined linear trend with LogP. Using the Bono et al. (2001) and Bono et al. (2003) theoretical Near-Infrared Period-Luminosity-Metallicity relations we calculate the LMC distance modulus 18.48+-0.08.

13 pages, 16 figures, A&A in press

References in corpus (19)

• Abundances for Globular Cluster Giants: I. Homogeneous Metallicities for 24 Clusters
• New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics
• Variable Stars in Galactic Globular Clusters
• A pulsational approach to near infrared and visual magnitudes of RR Lyrae stars
• The MACHO Project LMC Variable Star Inventory. IX. Frequency Analysis of the First Overtone RR Lyrae Stars and the Indication for Nonradial Pulsations
• Towards the absolute planes: a new calibration of the Bolometric Corrections and Temperature scales for Population II Giants
• The MACHO Project Large Magellanic Cloud variable star inventory. XI. Frequency analysis of the fundamental mode RR Lyrae stars
• The Rotation Curve of the Large Magellanic Cloud and the Implications for Microlensing
• Theoretical insights into the RR Lyrae K-band Period-Luminosity relation
• Self-Lensing Models of the LMC
• K-Band Red Clump Distance to the Large Magellanic Cloud
• Kinematic Evidence for an Old Stellar Halo in the Large Magellanic Cloud
• CCD Photometry of the Globular Cluster Omega Centauri. I. Metallicity of RR Lyrae Stars from Caby Photometry
• Metal Rich RR Lyrae Variables: I. The Evolutionary Scenario
• The MACHO Project Large Magellanic Cloud Variable Star Inventory. XIII. Fourier Parameters for the First Overtone RR Lyrae Variables and the LMC Distance
• The Optical Gravitational Lensing Experiment. Variable Stars in Globular Clusters - II. Fields 5139D-F in Omega Centauri
• Distances to Local Group Galaxies
• Spatial metallicity asymmetry in $\omega$ Centauri
• Cluster AgeS Experiment (CASE): RR Lyrae stars from the globular cluster Omega Centauri as standard candles

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