Gamma-ray flare activity from PSR B1259-63 during 2014 periastron passage and comparison to its 2010 passage

TL;DR

This paper reports on gamma-ray observations of PSR B1259-63 during its 2014 periastron, compares it with the 2010 event, and discusses the recurrent GeV flares and their phenomenology.

Contribution

It provides the first detailed comparison of gamma-ray activity during two periastron passages of PSR B1259-63, highlighting recurrent flares and their characteristics.

Findings

Recurrent GeV flares observed in both 2010 and 2014 periastron passages.

Similarities and differences in gamma-ray phenomenology between the two events.

Insights into the emission mechanisms of gamma-ray binaries.

Abstract

PSR B1259-63/LS 2883 is a gamma-ray binary system containing a radio pulsar in a highly elliptical ~3.4-year orbit around a Be star. In its 2010 periastron passage, multiwavelength emission from radio to TeV was observed, as well as an unexpected GeV flare measured by the Fermi Large Area Telescope (LAT). Here, we report the results of LAT monitoring of PSR B1259-63 during its most recent 2014 periastron passage. We compare the gamma-ray behavior in this periastron with the former in 2010 and find that PSR B1259-63 shows a recurrent GeV flare. The similarities and differences in the phenomenology of both periastron passages are discussed.