SIMILARITIES IN NEUTRON-STAR AND BLACK-HOLE ACCRETION

In this paper, I compare the X-ray properties of accreting low magnetic field neutron stars and accreting stellar mass black hole candidates. Rather than looking for signatures that are unique to black holes, I use the similarities in the observed properties of accreting neutron stars and black hole candidates in order to see whether it is possible to find a common pattern of phenomenology across the two groups. Following this purely phenomenological approach, I propose as a working hypothesis that three different states are common to the accretion process onto low magnetic field neutron stars and black holes. In a given source, the instantaneous accretion rate determines the state; between sources, other parameters, such as compact object mass and magnetic field strength, may also play a role.