High resolution Chandra X-ray imaging of the nucleus of M 33

We show with a short Chandra HRC-S exposure that the powerful X-ray source coincident with the nucleus of M 33 is unresolved at the highest spatial resolution available to date (0$\farcs$4). The source flux is variable, doubling during the 5 ks exposure. The combination of properties exhibited by M 33 X-8 establishes the source as the nearest example of the ultra-luminous X-ray sources that have been uncovered in other nearby galaxies. On short timescales, we set limits of 9% rms variability for pulsations in the 0.01–1000 Hz range.