Type Ia supernovae with early brightness spikes share a distinct identity

Scanning 1,547 nearby Type Ia supernovae from ZTF's second data release, the team identified 42 events with early-time flux excesses and compared them to 110 clean non-excess events. The excess group stands out sharply: their light curves are broader (SALT2 stretch offset at 7.9σ) and their local host environments are bluer and lower-mass. These correlations suggest early bumps are not random viewing-angle effects but are tied to the underlying explosion physics or progenitor channel, a distinction that will sharpen once larger photometric surveys push sample sizes higher.