The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs

Understand

We take advantage of more than 10 years of monitoring of the eclipsing HMXB systems LMC X-4, Cen X-3, 4U 1700-377, 4U 1538-522, SMC X-1, IGR J18027-2016, Vela X-1, IGR J17252-3616, XTE J1855-026, and OAO 1657-415 with the ASM on-board RXTE and ISGRI on-board INTEGRAL to update their ephemeris.

• These results are used to refine previous measurements of the orbital period decay of all sources (where available) and provide the first accurate values of the apsidal advance in Vela X-1 and 4U 1538-522.
• Updated values for the masses of the neutron stars hosted in the ten HMXBs are also provided, as well as the long-term lightcurves folded on the sources best determined orbital parameters.
• These lightcurves reveal complex eclipse ingresses and egresses, that are understood mostly as being due to the presence of accretion wakes.