LARGE MAGELLANIC CLOUD NEAR-INFRARED SYNOPTIC SURVEY. II. THE WESENHEIT RELATIONS AND THEIR APPLICATION TO THE DISTANCE SCALE

Abstract

ABSTRACT We present new near-infrared (NIR) Cepheid period–Wesenheit (P–W) relations in the LMC using time-series observations from the Large Magellanic Cloud NIR Synoptic Survey. We also derive optical+NIR P–W relations using V and I magnitudes from the Optical Gravitational Lensing Experiment. We employ our new JHK s data to determine an independent distance to the LMC of &mgr; LMC = 18.47 ± 0.07 ?> (statistical) mag, using an absolute calibration of the Galactic relations based on several distance determination methods and accounting for the intrinsic scatter of each technique. We also derive new NIR period–luminosity and Wesenheit relations for Cepheids in M31 using observations from the Panchromatic Hubble Andromeda Treasury survey. We use the absolute calibrations of the Galactic and LMC W J , H ?> relations to determine the distance modulus of M31, &mgr; M31 = 24.46 ± 0.20 ?> mag. We apply a simultaneous fit to Cepheids in several Local Group galaxies covering a range of metallicities ( 7.7 < 12 + log [ O / H ] < 8.6 ?> dex) to determine a global slope of −3.244 ± 0.016 mag dex−1 for the W J , K s ?> relation and obtain robust distance estimates. Our distances are in good agreement with recent TRGB based distance estimates and we do not find any evidence for a metallicity dependence in the NIR P–W relations.