Multi-wavelength View of the Type IIn Zoo: Optical to X-ray Emission Model of Interaction-Powered Supernovae

TL;DR

This paper presents a comprehensive model for the multi-wavelength emission of interaction-powered supernovae, successfully explaining observations from optical to X-ray wavelengths and predicting highly X-ray luminous transients detectable by surveys.

Contribution

The authors develop a time-dependent emission model for interaction-powered supernovae, incorporating plasma physics and radiation transfer, and validate it against observed Type IIn supernovae data.

Findings

Model explains optical and X-ray light curves of SN 2010jl with asymmetric CSM.

Successfully reproduces X-ray bremsstrahlung and Hα emission in SN 2014C.

Predicts extremely X-ray bright supernovae detectable by all-sky surveys.

Abstract

Transients powered by interaction with the circumstellar medium (CSM) are often observed in wavelengths other than optical, and multi-wavelength modelling can be important when inferring the properties of the explosion and CSM, or for distinguishing from other powering mechanisms. We develop a model calculating time dependent emission spectrum of interaction-powered transients. We solve energy equations of electron-proton plasma in the shocked SN ejecta and CSM and a radiation transfer equation out to the outer edge of the CSM, incorporating the collisional relaxation and the comptonization of the bremsstrahlung radiation. We compare our model to observations of Type IIn supernovae covering frequency ranges from optical to X-rays. For SN 2010jl the observed optical and X-ray light curves can be consistently explained if clumpy or asymmetric structure in the CSM is assumed, in agreement with previous studies. For SN 2014C our model successfully reproduces the X-ray bremsstrahlung component and the emergence of H$\alpha$ emission at 400 days after explosion. Finally we find a parameter space where the supernova is extremely X-ray bright, reaching $10^{43}$-$10^{44}\ {\rm erg\ s^{-1}}$ for up to $100$ days. Such X-ray transients are likely detectable with all-sky surveys by e.g. eROSITA.