The Swift-BAT hard X-ray sky monitoring unveils the orbital period of the HMXB IGR J16493-4348

Abstract

Abstract IGR J16493−4348 is a supergiant high-mass X-ray binary discovered by INTEGRAL in 2004. The source is detected at a significance level of ∼21 standard deviations in the Swift Burst Alert Telescope survey data collected during the first 54 months of the Swift mission. The timing analysis reveals an orbital period of ∼6.78 d and the presence of a full eclipse of the compact object. The dynamical range (variability up to a factor of ∼20) observed during the BAT monitoring suggests that IGR J16493−4348 is a wind-fed system. The derived semimajor axis of the binary system is ∼55 R⊙ with an orbit eccentricity lower than 0.15.