Defining Photometric Peculiar Type Ia Supernovae

TL;DR

This paper introduces a new photometric method to identify peculiar Type Ia supernovae, including 91bg-like, SNe Iax, and super-Chandrasekhar types, facilitating their study in large surveys.

Contribution

A novel photometric classification technique that distinguishes peculiar SNe Ia sub-types from normal ones based on light-curve features.

Findings

The method effectively identifies 91bg-like SNe Ia.

It also classifies SNe Iax and super-Chandrasekhar SNe Ia.

Peculiar and normal SNe Ia share similar photometric traits.

Abstract

We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e. objects with light-curve characteristics such as later primary maxima and absence of secondary peak in redder filters. This method is capable of selecting out this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have similar photometric characteristics as 91bg-like SNe Ia, namely the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large up-coming wide field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.