Near-infrared observations of OGLE classical and type II Cepheid variables in the LMC

TL;DR

This study uses near-infrared observations of Cepheid variables in the LMC to refine Period-Luminosity relations, revealing non-linearity around 10-18 days and improving distance estimates to galaxies and clusters.

Contribution

It provides new non-linear Period-Luminosity and Wesenheit relations for Cepheids using combined optical and near-infrared data, enhancing distance measurement accuracy.

Findings

Fundamental-mode Cepheid PL relations are non-linear around 10-18 days.

Non-linear relations better constrain Cepheid-based distances in SNe Ia host galaxies.

Results have negligible impact on local Hubble constant measurements.

Abstract

We present results from the Large Magellanic Cloud Near-infrared Synoptic Survey (LMCNISS) for classical and type II Cepheid variables that were identified by the Optical Gravitational Lensing Experiment (OGLE-III) catalogue. Multiwavelength time-series data for classical Cepheid variables are used to study light-curve structures as a function of period and wavelength. We exploit a sample of $\sim$1400 classical and $\sim$80 type II Cepheid variables to derive Period--Wesenheit relations that combine both optical and near-infrared data. The new Period--Luminosity and Wesenheit relations are used to estimate distances to several Local Group galaxies (using classical Cepheids) and to Galactic globular clusters (using type II Cepheids). By appealing to a statistical framework, we find that fundamental-mode classical Cepheid Period--Luminosity relations are non-linear around 10--18 days at optical and near-IR wavelengths. We also suggest that a non-linear relation provides a better constraint on the Cepheid Period--Luminosity relation in type Ia Supernovae host galaxies, though it has a negligible effect on the systematic uncertainties affecting the local measurement of the Hubble constant.