PSR J1119-6127 and its pulsar wind nebula following the magnetar-like bursts

TL;DR

This study reports on Chandra X-ray observations of PSR J1119-6127 and its pulsar wind nebula following magnetar-like bursts, revealing increased brightness, spectral characteristics, and structural features that suggest additional energy sources beyond rotation.

Contribution

First observation of magnetar-like activity from a rotation-powered pulsar, providing insights into the physical processes differentiating pulsars from magnetars.

Findings

Pulsar's X-ray flux increased by over 160 times post-burst.

The nebula's brightness and structure changed, indicating additional energy input.

The pulsar's spectrum is well described by a powerlaw model with photon index ~2.

Abstract

We present a Chandra Director's Discretionary Time observation of PSR J1119-6127 and its compact X-ray pulsar wind nebula (PWN) obtained on 27 October 2016, three months after the Fermi and Swift detection of millisecond bursts in hard X-rays, accompanied by >160 times increase in flux. This magnetar-like activity, the first observed from a rotation-powered radio pulsar, provides an important probe of the physical processes that differentiate radio pulsars from magnetars. The post-burst X-ray spectrum of the pulsar can be described by a single powerlaw model with a photon index of 2.0\pm0.2 and an unabsorbed flux of 5.7e-12 ergs/cm^2/s in the 0.5-7.0 keV energy range. At the time of Chandra observations, the pulsar was still brighter by a factor of ~22 in comparison with its quiescence. The X-ray images reveal a nebula brighter than in the pre-burst Chandra observations (from 2002 and 2004), with an unabsorbed flux of 2.2e-13 ergs/cm^-2/s. This implies a current X-ray efficiency of ~0.001 at a distance of 8.4 kpc. In addition, a faint torus-like structure is visible along the southeast-northwest direction and a jet-like feature perpendicular to the torus towards the southwest. The PWN is best fitted by an absorbed powerlaw with a photon index of 2.2\pm0.5 (post-burst). While the pulsar can still be energetically powered by rotation, the observed changes in PSR~J1119-6127 and its PWN following the magnetar-like bursts point to an additional source of energy powered by its high-magnetic field.