H-band light curves of Milky Way Cepheids via Difference Imaging

TL;DR

This paper presents H-band light curves of Milky Way Cepheids obtained through difference imaging, achieving high photometric precision and providing phase corrections for HST observations, thereby improving distance measurements.

Contribution

It introduces a modified difference-imaging pipeline for crowded fields and demonstrates its effectiveness in deriving accurate Cepheid light curves in the H-band.

Findings

Achieved 0.01 mag photometric precision for 8 <= H <= 11 mag.

Derived phase corrections consistent with previous VI-based corrections.

Provided improved H-band light curves for Milky Way Cepheids.

Abstract

We present H-band light curves of Milky Way Classical Cepheids observed as part of the DEHVILS survey with the Wide-Field Infrared Camera on the United Kingdom InfraRed Telescope. Due to the crowded nature of these fields caused by defocusing the Camera, we performed difference-imaging photometry by modifying a pipeline originally developed to analyze images from the Transiting Exoplanet Survey Satellite. We achieved a photometric precision in line with expectations from photon statistics, reaching 0.01 mag for 8 <= H <= 11 mag. We used the resulting Cepheid light curves to derive corrections to "mean light" for random-phase Hubble Space Telescope observations in F160W. We find good agreement with previous phase corrections based on VI light curves from the literature, with a mean difference of -1 +/- 6 millimag.