2005A&A...439..255H

We report the association of the INTEGRAL source IGR J18027-2016 with the BeppoSAX source SAX J1802.7-2017. IGR J18027-2016 is seen to be a weak, persistent source by the IBIS/ISGRI instrument on board INTEGRAL with an average source count rate of 0.58-counts/s (∼6.4mCrab) in the 20-40keV band. Timing analysis performed on the ISGRI data identifies an orbital period of of 4.5696±0.0009 days and gives an ephemeris of mid-eclipse as, T_mid=52931.37±0.04MJD. Re-analysis of archival BeppoSAX data has provided a mass function for the donor star, f(m)=16±1M_☉ and a projected semimajor axis of a_xsini=68±1 lt-s. We conclude that the donor is an OB-supergiant with a mass of 18.8-29.3M_☉ and a radius of 15.0-23.4R_☉. Spectra obtained by XMM-Newton and ISGRI indicate a high hydrogen column density of N_H=6.8x10²²cm^–2, which suggests intrinsic absorption. The source appears to be a high mass X-ray binary with the neutron star emitting X-rays through wind-fed accretion while in an eclipsing orbit around an OB-supergiant.