The PSR J1124-5916 wind nebula in the near-infrared

TL;DR

This study identifies the near-infrared counterpart of the pulsar wind nebula associated with PSR J1124-5916, revealing complex spectral features and multiple relativistic particle populations through deep adaptive optics observations.

Contribution

First near-infrared detection of the pulsar wind nebula in PSR J1124-5916, showing spectral breaks and suggesting multiple particle populations responsible for synchrotron emission.

Findings

Detected faint extended elliptical object consistent with the nebula in H and Ks bands.

Observed a complex unabsorbed power law spectrum with multiple spectral breaks.

Placed upper limits on the pulsar's near-infrared brightness, indicating a minor contribution to the total flux.

Abstract

The young radio pulsar J1124-5916 is associated with a Cas A like supernova remnant G292.0+1.8. It powers a compact torus-like pulsar wind nebula with a jet first detected in X-rays and then identified in the optical and mid-infrared. We carried out deep near-infrared observations of the pulsar field to identify the pulsar and its nebula in this range. The direct imaging mode of the NACO adaptive optics instrument at the ESO VLT in the H and Ks bands was used. In both bands we detected a faint, H=21.30(10) and Ks=20.45(10), extended elliptical object, whose center position is consistent with the X-ray position of the pulsar. The morphology of the object and the orientation of its major axis are in a good agreement with those observed for the pulsar torus-like nebula in the mid-infrared, optical, and X-rays. This suggests that it is the near-infrared counterpart of the nebula. The measured fluxes compiled with the data in other ranges show a complicated unabsorbed power law spectrum of the torus-like nebula with several steep breaks between the near-infrared and mid-infrared, the optical and X-rays, and possibly in the mid-infrared. This implies a multiple relativistic particle population responsible for the synchrotron emission of the nebula in different spectral ranges. We have not resolved the pulsar counterpart from its nebula and place only upper limits on its brightness, H >= 23.9$ and Ks >= 22.7. Based on that, its contribution to the total near-infrared flux of the pulsar+nebula system is <= 10%, which is comparable with the expected contribution in the optical.