The Swift-BAT survey reveals the orbital period of three high-mass X-ray binaries

Aims. A growing number of previously hidden Galactic X-ray sources are now detected with recent surveys performed by the INTEGRAL and Swift satellites. Most of these new sources eluded past surveys due to their large local X-ray extinction and consequent low soft X-ray flux. The Swift-BAT performs daily monitoring of the sky in an energy band (15–150 keV) which is only marginally affected by X-ray extinction, thus allowing for the search of long periodicities in the light curve and identification of the nature of the X-ray sources. Methods. We performed a period search using the folding technique in the Swift-BAT light curves of three INTEGRAL sources: IGR J05007−704