The masses of the neutron and donor star in the high-mass X-ray binary IGR J18027-2016

A.B.M. acknowledges support from an STFC studentship. J.S.C. acknowledges support from an RCUK fellowship. This research is partially supported by grants AYA2008-06166-C03-03 and Consolider-GTC CSD-2006-00070 from the Spanish Ministerio de Ciencia e Innovacion (MICINN).