Cluster AgeS Experiment (CASE): RR Lyrae stars from the globular cluster Omega Centauri as standard candles

Abstract

New photometry of RRab and RRc stars in Omega Cen is used to calibrate their absolute magnitudes M_V as a function of: a) metallicity; and b) the Fourier parameters of light curves in the V band. The zero point of both calibrations relies on the distance modulus to the cluster derived earlier by the CASE project based on observations of the detached eclipsing binary OGLE GC17. For RRab variables we obtained a relation of M_V=(0.26\pm 0.08)[Fe/H]+(0.91\pm 0.13). A dereddened distance modulus to the LMC based on that formula is ${\mu }_0=18.56\pm 0.14$ mag. The second calibration of M_V, which is based on Fourier coefficients of decomposed light curves, results in the LMC distance of ${\mu }_0=18.51\pm 0.07$ mag.

arXiv commentaccepted for publication in MNRAS, 13 pages, 8 figures

References in corpus (18)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Ages of Globular Clusters from Hipparcos Parallaxes of Local Subdwarfs
• Cluster AgeS Experiment: The Age and Distance of the Globular Cluster omega Centauri Determined from Observations of the Eclipsing Binary OGLEGC17
• The \mv vs \fe Calibration: I. HST Color-Magnitude Diagrams of 8 Globular Clusters in M 31
• Pulsational M_V versus [Fe/H] relation(s) for globular cluster RR Lyrae variables
• Systematics of RR Lyrae Statistical Parallax III: Apparent Magnitudes and Extinctions
• The Optical Gravitational Lensing Experiment. Red Clump Stars as a Distance Indicator
• K-Band Red Clump Distance to the Large Magellanic Cloud
• Globular Cluster Distance Determinations
• Empirical relations for cluster RR Lyrae stars revisited
• CCD Photometry of the Globular Cluster Omega Centauri. I. Metallicity of RR Lyrae Stars from Caby Photometry
• The ARAUCARIA project: Deep near-infrared survey of nearby galaxies. I. The distance to the Large Magellanic Cloud from K-band photometry of red clump stars
• On the Light Curve - Luminosity Relation of RR Lyrae Stars
• Background galaxies as reddening probes throughout the Magellanic Clouds
• The Optical Gravitational Lensing Experiment. Variable Stars in Globular Clusters - II. Fields 5139D-F in Omega Centauri
• K-Band Red Clump Distances to the LMC Clusters Hodge 4 and NGC 1651
• The LMC eclipsing binary HV 2274 revisited
• The Distance to the Magellanic Clouds

Cited by in corpus (9)

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• A multi-color and Fourier study of RR Lyrae variables in the globular cluster NGC 5272 (M3)
• The calibration of the RGB Tip as a Standard Candle: Extension to Near Infrared colors and higher metallicity
• Distance Scale Zero-Points from Galactic RR Lyrae Star Parallaxes
• [Fe/H] relations for c-type RR Lyrae Variables based upon Fourier Coefficients
• The distance to the LMC cluster Reticulum from the K-band Period-Luminosity-Metallicity relation of RR Lyrae stars
• Properties of RR Lyrae stars in the Inner Regions of the Large Magellanic Cloud
• Cluster AgeS Experiment. Catalog of Variable Stars in the Globular Cluster Omega Centauri
• Metallicity Analysis of MACHO Galactic Bulge RR0 Lyrae stars from their Lightcurves