Abstract
Abstract We present H-band light curves of Milky Way classical Cepheids observed as part of the Dark Energy, H 0, and peculiar Velocities using Infrared Light from Supernovae 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 mmag.
Highlights
For over a hundred years, classical Cepheid variables have been known to follow Period–Luminosity relations (PLRs; Leavitt 1908; Leavitt & Pickering 1912)
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
Hubble Space Telescope (HST) observations of Milky Way (MW) Cepheids can play a critical role in local H0 measurements, as they can be simultaneously used to determine the Gaia parallax offset for Cepheids and reduce the zeropoint errors that arise while comparing MW Cepheids to extragalactic variables
Summary
For over a hundred years, classical Cepheid variables (hereafter Cepheids) have been known to follow Period–Luminosity relations (PLRs; Leavitt 1908; Leavitt & Pickering 1912). Hubble Space Telescope (HST) observations of MW Cepheids can play a critical role in local H0 measurements, as they can be simultaneously used to determine the Gaia parallax offset for Cepheids and reduce the zeropoint errors that arise while comparing MW Cepheids to extragalactic variables Such observations were obtained for 29/40 targets during HST Cycle 27 (prop #15879, PI Riess). Riess et al (2021) presented results based on all observations obtained for this program through the end of 2020 (25/29 targets), relying on VI data for phase corrections They obtained H0 = 73.2 ± 1.3 km/s/Mpc, a 1.8% measurement that exceeds the Planck CMB+ΛCDM expectation by 4.2σ. The Cepheid light curves and compares the derived phase corrections to HST observations to similar corrections based on V I light curves, and §5 provides a summary of this work
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