The Progenitors of Calcium-Strong Transients

Understand

A new class of faint, spectroscopically peculiar transients has emerged in the last decade.

• We term these events "calcium-strong transients" (CaSTs) because of their atypically high calcium-to-oxygen nebular line ratios.
• Previous studies have struggled to deduce the identity of their progenitors due to a combination of their extremely extended radial distributions with respect to their host galaxies and their relatively high rate of occurrence.
• In this work, we find that the CaST radial distribution is consistent with the radial distribution of two populations of stars: old (ages > 5 Gyr), low-metallicity (Z/Zsol < 0.3) stars and globular clusters.