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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.
We report optical spectroscopic observations of the Be/gamma-ray binaries LSI+61303, MWC 148 and MWC 656. The peak separation and equivalent widths of prominent emission lines (H-alpha, H-beta, H-gamma, HeI, and FeII) are measured. We estimated the c
Using TESS photometry and Rozhen spectra of the Be/gamma-ray binaries MWC 148 and MWC 656, we estimate the projected rotational velocity ($ {v} sin i$), the rotational period (P$_{rm rot}$), radius (R$_{rm 1}$), and inclination ($i$) of the mass dono
We present results obtained from an extensive near-infrared spectroscopic and photometric observations of the Be/X-ray binary A0535+262/HDE 245770 at different phases of its ~111 day orbital period. This observation campaign is a part of the monitori
During normal Type I outbursts, the pulse profiles of Be/X-ray binary pulsars are found to be complex in soft X-ray energy ranges. The profiles in soft X-ray energy ranges are characterized by the presence of narrow absorption dips or dip-like featur
We present an optical and X-ray study of four Be/X-ray binaries located in the Small Magellanic Cloud (SMC). OGLE I-band data of up to 11 years of semi-continuous monitoring has been analysed for SMC X-2, SXP172 and SXP202B, providing both a measurem