JWST Photometric Time-Delay and Magnification Measurements for the Triply-Imaged Type Ia "Supernova H0pe" at z = 1.78

Supernova (SN) H0pe is a gravitationally lensed, triply-imaged, Type Ia SN (SN Ia) discovered in James Webb Space Telescope imaging of the PLCK G165.7+67.0 cluster of galaxies. Well-observed multiply-imaged SNe provide a rare opportunity to constrain the Hubble constant (H₀), by measuring the relative time delay between the images and modeling the foreground mass distribution. SN H0pe is located at $z=1.783$, and is the first SN Ia with sufficient light curve sampling and long enough time delays for an H₀ inference. Here we present photometric time-delay measurements and SN properties of SN H0pe. Using JWST/NIRCam photometry we measure time delays of Δ tab=-116.6+10.8-9.3 and Δ tcb=-48.6+3.6-4.0 observer-frame days relative to the last image to arrive (image 2b; all uncertainties are 1σ), which corresponds to a ~5.6% uncertainty contribution for H₀ assuming 70 km s⁻¹ Mpc⁻¹. We also constrain the absolute magnification of each image to μₐ=4.3+1.6-1.8, μb=7.6+3.6-2.6, μc=6.4+1.6-1.5 by comparing the observed peak near-IR magnitude of SN H0pe to the non-lensed population of SNe Ia.