A NuSTAR and Chandra Investigation of the Misaligned Outflow of PSR J1101-6101 and the Lighthouse Pulsar Wind Nebula

TL;DR

This study uses NuSTAR and Chandra observations to analyze the misaligned outflow of PSR J1101-6101, revealing spectral cooling, particle properties, and the outflow's structure, advancing understanding of pulsar wind nebulae.

Contribution

First NuSTAR observation of the misaligned outflow above 10 keV, resolving its spectral evolution and providing insights into its physical properties and structure.

Findings

Detected the outflow up to 25 keV with spectral cooling evidence.

Resolved the spectral evolution and inferred particle and magnetic field properties.

Confirmed pulsations up to 20 keV and analyzed the pulsar's phase-resolved spectrum.

Abstract

PSR J1101-6101 is an energetic young pulsar which powers the remarkable Lighthouse pulsar wind nebula (PWN). The pulsar belongs to the rare type of radio- and gamma-ray-quiet pulsars which are bright in hard X-rays. Moreover, the Lighthouse PWN is remarkable for its misaligned outflow (which gave rise to the PWN's nickname). Also known as "pulsar filaments", these collimated parsec-scale X-ray structures have been recently discovered in the vicinity of a handful of fast-moving pulsars, and appear unaffected by the ram pressure which confines pulsar tails. We report on NuSTAR observations of PSR J1101-6101 and its misaligned outflow -- the first observation of such a structure above ~10 keV. We detect the outflow up to 25 keV, spatially resolve its spectral evolution with distance from the pulsar, find unambiguous evidence of spectral cooling with distance from the pulsar, and infer physical properties of the particles and magnetic field in the outflow. We also reanalzye archival Chandra data and discuss the outflow's small-scale structure. We detect pulsations from PSR J1101-6101 up to 20 keV, present the X-ray pulse profile, confirm its period derivative, and perform phase-resolved spectroscopy. Lastly, we discuss the X-ray source 2CXO J110158.4-605649 = 2XMM J110158.5--605651 (a serendipitously observed blazar) and suggest it may be the X-ray counterpart to the GeV source 4FGL J1102.0--6054.