Large Magellanic Cloud Near-Infrared Synoptic Survey. I. Cepheid variables and the calibration of the Leavitt Law

TL;DR

This study provides a comprehensive near-infrared survey of the Large Magellanic Cloud, significantly expanding the sample of Cepheid variables to refine the calibration of the Leavitt Law and improve distance measurements.

Contribution

It presents the largest near-infrared Cepheid sample to date and offers a highly precise calibration of the Leavitt Law, enhancing the accuracy of cosmic distance measurements.

Findings

Expanded Cepheid sample by 9 times with multi-band near-infrared data

Derived a robust calibration of the Leavitt Law with improved slope constraints

Confirmed consistency of Tip of the Red Giant Branch and Red Clump calibrations with previous studies

Abstract

We present observational details and first results of a near-infrared (JHKs) synoptic survey of the central region of the Large Magellanic Cloud using the CPAPIR camera at the CTIO 1.5-m telescope. We covered 18 sq. deg. to a depth of Ks~16.5 mag and obtained an average of 16 epochs in each band at any given location. Our catalog contains more than 3.5x10^6 sources, including 1417 Cepheid variables previously studied at optical wavelengths by the OGLE survey. Our sample of fundamental-mode pulsators represents a 9-fold increase in the number of these variables with time-resolved, multi-band near-infrared photometry. We combine our large Cepheid sample and a recent precise determination of the distance to the LMC to derive a robust absolute calibration of the near-infrared Leavitt Law for fundamental-mode and first-overtone Cepheids with 10x better constraints on the slopes relative to previous work. We also obtain calibrations for the Tip of the Red Giant Branch and the Red Clump based on our ensemble photometry which are in good agreement with previous determinations.