Spectral variability in the orbital profiles of TeV Binary LSI + 61o 303 in X-Ray window using XMM - Newton Observations

Abstract

LSI + 61o 303 is a high-mass X-ray binary consisting of a low-mass [M (1 - 4)M ] compact object orbiting around an early type B0 Ve star along an eccentric e = 0:7 orbit. It along with LS5039 are the only two known gamma-ray binary detected in the TeV band. Despite extensive observations the nature of this source, particularly whether it is a pulsar or a black hole (microquasar) system, is not clear. The mechanisms that lead to the multi-wavelength behavior are also uncertain. Recent approach to the study of LSI + 61o 303 has been to focus on possible correlated variability. There was an early indication that there is a correlation between the X-ray and TeV emission at the time where the latter was measurable. In a more recent observation, however, such a feature has not been found. In this work, we study the spectral variability of LSI + 61o 303 using four observations between 2001 to 2007 of XMM - Newton available from NASA archive and examine the correlation between low energy range and high energy part.