Indication of a Pulsar Wind Nebula in the hard X-ray emission from SN 1987A

TL;DR

This study analyzes archival X-ray data from SN 1987A to identify nonthermal emission, providing evidence that supports the presence of a pulsar wind nebula within the supernova remnant.

Contribution

The paper presents the first strong evidence for a pulsar wind nebula in SN 1987A by combining observational data with advanced magneto-hydrodynamic simulations.

Findings

Detection of nonthermal X-ray emission in 10-20 keV band

Emission likely powered by a pulsar wind nebula rather than shock acceleration

Reconstructed absorption pattern consistent with a PWN embedded in ejecta

Abstract

Since the day of its explosion, SN 1987A (SN87A) was closely monitored with the aim to study its evolution and to detect its central compact relic. The detection of neutrinos from the supernova strongly supports the formation of a neutron star (NS). However, the constant and fruitless search for this object has led to different hypotheses on its nature. Up to date, the detection in the ALMA data of a feature somehow compatible with the emission arising from a proto Pulsar Wind Nebula (PWN) is the only hint of the existence of such elusive compact object. Here we tackle this 33-years old issue by analyzing archived observations of SN87A performed Chandra and NuSTAR in different years. We firmly detect nonthermal emission in the $10-20$ kev energy band, due to synchrotron radiation. The possible physical mechanism powering such emission is twofold: diffusive shock acceleration (DSA) or emission arising from an absorbed PWN. By relating a state-of-the-art magneto-hydrodynamic simulation of SN87A to the actual data, we reconstruct the absorption pattern of the PWN embedded in the remnant and surrounded by cold ejecta. We found that, even though the DSA scenario cannot be firmly excluded, the most likely scenario that well explains the data is the PWN emission.