The X-ray binary system in the EP era

Searching for X-ray binaries and establishing a large sample are the foundation of answering many scientific problems, such as, how many BH X-ray binaries are there within our Milky Way galaxy? Does there exist a real gap between the mass distribution of neutron stars and black holes? Is there any black hole system within globular clusters? The planned mission Einstein Probe (EP) has a much better sensitivity compared to the past missions, so it is expected to discover many new X-ray binary systems over its operating period, which will play a key role in helping solve the problems above then.