Optical and Near-Infrared Monitoring of Gamma-ray Binaries Hosting Be Stars

TL;DR

This study presents optical and near-infrared observations of three gamma-ray binaries with Be stars, analyzing how their emissions vary with orbital phase due to interactions between the Be disk and the compact object.

Contribution

It provides multi-band photometry and polarization data for three gamma-ray binaries, highlighting the impact of orbital interactions on observable emissions.

Findings

Variations in Be disk emissions linked to orbital phase.

Interactions with the compact object influence observable properties.

Multi-band monitoring reveals phase-dependent emission changes.

Abstract

Optical and near-infrared observations are compiled for the three gamma-ray binaries hosting Be stars: PSR B1259-63, LSI+61 303, and HESS J0632+057. The emissions from the Be disk are considered to vary according to the changes in its structure, some of which are caused by interactions with the compact object (e.g., tidal forces). Due to the high eccentricity and large orbit of these systems, the interactions -- and, hence the resultant observables -- depend on the orbital phase. To explore such variations, multi-band photometry and linear polarization were monitored for the three considered systems, using two 1.5 m-class telescopes: IRSF at the South African Astronomical Observatory and Kanata at the Higashi-Hiroshima Observatory.