Evidence for Two Distinct Populations of Type Ia Supernovae

Understand

Type Ia supernovae (SNe Ia) have been used as excellent standardizable candles for measuring cosmic expansion, but their progenitors are still elusive.

• Here we report that the spectral diversity of SNe Ia is tied to their birthplace environments.
• We find that those with high-velocity ejecta are substantially more concentrated in the inner and brighter regions of their host galaxies than are normal-velocity SNe Ia.
• Furthermore, the former tend to inhabit larger and more-luminous hosts.