The JWST Discovery of the Triply-imaged Type Ia "Supernova H0pe" and Observations of the Galaxy Cluster PLCK G165.7+67.0

Understand

A Type Ia supernova (SN) at $z=1.78$ was discovered in James Webb Space Telescope Near Infrared Camera imaging of the galaxy cluster PLCK G165.7+67.0 (G165; $z = 0.35$).

• The SN is situated 1.5-2 kpc from the host-galaxy nucleus and appears in three different locations as a result of gravitational lensing by G165.
• These data can yield a value for Hubble's constant using time delays from this multiply-imaged SN Ia that we call "SN H0pe." Over the cluster, we identified 21 image multiplicities, confirmed five of them using the Near-Infrared Spectrograph, and constructed a new lens model that gives a total mass within 600 kpc of ($2.6 \pm 0.3) \times 10^{14}$ $M_{\odot}$.
• The photometry uncovered a galaxy overdensity coincident with the SN host galaxy.