ALMA and NOEMA constraints on synchrotron nebular emission from embryonic superluminous supernova remnants and radio-gamma-ray connection

TL;DR

This study uses ALMA and NOEMA radio observations to constrain the synchrotron emission from nascent pulsar wind nebulae in superluminous supernovae, challenging existing models and proposing new scenarios for nebular magnetization.

Contribution

It provides the first high-frequency radio constraints on PWN models in SLSNe and introduces a detailed theoretical framework to interpret these emissions.

Findings

ALMA data disfavor Crab-like PWN models for some SLSNe

High or low nebular magnetization can reconcile observations with models

Future gamma-ray telescopes can test these PWN scenarios

Abstract

Fast-rotating pulsars and magnetars have been suggested as the central engines of super-luminous supernovae (SLSNe) and fast radio bursts, and this scenario naturally predicts non-thermal synchrotron emission from their nascent pulsar wind nebulae (PWNe). We report results of high-frequency radio observations with ALMA and NOEMA for three SLSNe (SN 2015bn, SN 2016ard, and SN 2017egm), and present a detailed theoretical model to calculate non-thermal emission from PWNe with an age of about 1-3 yr. We find that the ALMA data disfavors a PWN model motivated by the Crab nebula for SN 2015bn and SN 2017egm, and argue that this tension can be resolved if the nebular magnetization is very high or very low. Such models can be tested by future MeV-GeV gamma-ray telescopes such as AMEGO.