The 1–50 keV spectral and timing analysis of IGR J18027-2016: an eclipsing, high mass X-ray binary

A. B. Hill, R. Walter, C. Knigge, A. Bazzano, G. Bélanger, A. J. Bird, A. J. Dean, J. L. Galache, A. Malizia, M. Renaud, J. Stephen, P. Ubertini
2005 Astronomy and Astrophysics  
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 0.55 counts s^-1 ( 6.1 mCrab) in the 20-40 keV band. Timing analysis performed on the ISGRI data identifies an orbital period of 4.5696 +/- 0.0009 days and gives an ephemeris of mid-eclipse as, Tmid = 52931.37 +/- 0.04 MJD. Re-analysis of archival
more » ... oSAX data has provided a mass function for the donor star, f(m) = 16 +/- 1 Msun and a projected semimajor axis of axsini = 68 +/- 1 lt-s. We conclude that the donor is an OB-supergiant with a mass of 18.8-29.3 Msun and a radius of 15.0-23.4 Rsun. Spectra obtained by XMM-Newton and ISGRI indicate a high hydrogen column density of NH = 6.8 x 10^22 cm^-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.
doi:10.1051/0004-6361:20052937 fatcat:be4x6zhg4ze3vf6hj2uklinxje