# XMM-Newton and Chandra observations of the unidentified Fermi-LAT source 3FGL J1016.5-6034: A Young Pulsar with a Nebula?

## TL;DR

This paper reports the discovery of a young pulsar with a nebula associated with an unidentified Fermi-LAT source, based on X-ray and gamma-ray observations revealing a point source, surrounding nebula, and extended emission.

## Contribution

The study presents the first identification of a young pulsar with a nebula linked to 3FGL J1016.5-6034, combining X-ray spectral analysis and gamma-ray localization.

## Key findings

- Detection of a point X-ray source with a surrounding nebula.
- Spectral properties consistent with a young pulsar and pulsar wind nebula.
- Gamma-ray localization aligns with the X-ray source position.

## Abstract

We report the discovery of a bright X-ray source in the XMM-Newton and Chandra X-ray Observatory (CXO) images of the unidentified Fermi-LAT source 3FGL J1016.5-6034. The XMM-Newton spectrum of the source is well fit by an absorbed blackbody+power-law model with a temperature, $kT=0.20\pm0.02$ keV, and photon index $\Gamma=1.8\pm0.1$. The CXO resolves the same source into a point source (CXOU J101546.0-602939) and a surrounding compact nebula seen up to about $30''$ from the point source. The CXO spectrum of the nebula can be described by an absorbed power-law with $\Gamma=1.7\pm0.3$ and is partly responsible for the non-thermal emission observed in the XMM-Newton spectrum. The XMM-Newton images also reveal faint extended emission on arcminute scales. These properties strongly suggest that the X-ray source and the accompanying extended emission are a newly discovered young pulsar with a pulsar wind nebula. We also analyze $\sim10$ years of Fermi-LAT data and find that the improved LAT source localization is consistent with the position of CXOU J101546.0-602939.