Gap Transients Interacting with Circumstellar Medium

Understand

In the last 20 years, modern wide-field surveys discovered a new class of peculiar transients, which lie in the luminosity gap between standard supernovae and classical novae.

• These transients are often called 'intermediate luminosity optical transients' or 'gap transients'.
• They are usually distinguished in subgroups based on their phenomenology, such as supernova impostors, intermediate luminosity red transients, and luminous red novae.
• In this review, we present a brief overview of their observational features and possible physical scenarios to date, in the attempt to understand their nature.