Speaker
Description
Large-scale structure in the nearby Universe is traditionally traced by galaxies and clusters, but wide-field time-domain surveys now allow Type Ia supernovae (SNe Ia) to serve as an additional probe of the cosmic web. Using the second Type Ia supernova data release from the Zwicky Transient Facility (ZTF), I show that SNe Ia exhibit significant spatial clustering, with overdensities closely tracing known galaxy clusters and large-scale structures at low redshift. These inhomogeneities enable direct tests of environmental dependencies in SN Ia light-curve properties, including correlations in stretch and color, while also introducing additional covariance in cosmological analyses through shared bulk flows and common environments. At the same time, the high concentration of SNe Ia within individual structures provides new opportunities to constrain the mass and dynamics of nearby large-scale structures.