Variability of VHE $\gamma$-ray emission from the binary PSR B1259-63/LS 2883

TL;DR

This paper analyzes gamma-ray emission variability from the binary system PSR B1259-63/LS 2883 during periastron passages, revealing intrinsic source activity changes using a straightforward photon count method.

Contribution

It introduces a simple method to detect gamma-ray variability using high-energy photon counts, applicable to existing observational data.

Findings

Detected significant intrinsic gamma-ray activity variations.

Method effectively identifies source variability despite detection uncertainties.

Results support dynamic emission behavior around periastron passages.

Abstract

We examine changes of the $\gamma$-ray intensity observed from the direction of the binary system PSR B1259-63/LS 2883 during campaigns around its three periastron passages. A simple and straightforward method is applied to the published data obtained with the Imaging Atmospheric Cherenkov Technique. Regardless of many issues of the detection process, the method works only with numbers of very high energetic photons registered in the specified regions. Within the realm of this scheme, we recognized changes attributable to the variations of the intrinsic source activity at high levels of significance.