The eclipsing X-ray pulsar X-7 in M33
arXiv:astro-ph/9810050 · doi:10.1046/j.1365-8711.1999.02158.x
Abstract
Using our extensive ROSAT X-ray observations of M33, we confirm a 3.45 day eclipse period for the Einstein source X-7 (Larson & Schulman, 1997) and discover evidence for a 0.31-s pulse period. The orbital period, pulse period and observed X-ray luminosity are remarkably similar to SMC X-1. We therefore suggest M33 X-7 is a neutron star high mass X-ray binary with a 15-40 Msol O/B companion and a binary separation of 25-33 Rsol if the companion is almost filling its Roche lobe.
accepted for publication in MNRAS