Abstract
There are over 400 very luminous (Lx ~ 1e38-1e40 erg/s) globular cluster X-ray sources in nearby galaxies. None are present in our Galaxy, and their nature is unknown. They may be accreting black holes, however, this is quite controversial and it is contrary to theoretical expectations. The distance is too large to make accurate studies of any of them that could reveal their nature. Luckily, there is one such very luminous source, Bo375, in a globular cluster in M31. We propose to perform ten 10 ksec observations of Bo375 and we expect that we will be able to determine the nature of this object.