|Title:||NIR monitoring observations of the TeV gamma-ray binaries|
|Date:||Thursday, 30 March 2017|
|Time:||11:00 - 12:00|
Five binary systems have been confirmed to emit TeV gamma-rays modulating with orbital phase. All of them are high-mass X-ray binaries and emit the high-energy radiations by the interaction of the accelerated outflow of the compact star with the stellar wind (and/or) the gas disc of the massive star. But the parameters of the binaries are rich in variety and any common model for orbital variability is difficult to be derived. We have performed the NIR photometric monitoring observations of 4 binaries using the IRSF/SAAO in order to study the parameters of the massive stars and perturbations caused by the binary interactions. Regular brightenings at the periastron have been observed for the pulsar-Be star binary, PSR B1259-63 and a hint of periastron flare was detected for another Be-star system, HESSJ0632+057. Since the variability detected/expected is very small, we have tried to improve the observation methods for higher photometric precision. The summary of the observations and results are presented.