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We obtained U_330 and B band images of the M31 nucleus using the HighResolution Camera of the Advanced Camera for Surveys on board the Hubble SpaceTelescope (HST). The spatial resolution in the U_330-band, 0.03" FWHM, or 0.1pc at M31, is sufficient to resolve the outskirts of the compact cluster (P3)of UV-bright stars surrounding the M31 black hole. The center of the cluster ismarked by an extended source that is both brighter and redder than the otherpoint sources within P3; it is likely to be a blend of several bright stars. Wehypothesize that it marks the location of the M31 black hole. Both stellarphotometry and a surface brightness fluctuation analysis, show that the P3stellar population is consistent with early-type main sequence stars formed ina ~100 - ~200 Myr old starburst population. Evolutionary tracks of post earlyasymptotic giant-branch stars, associated with late-stage evolution of an oldpopulation, also traverse the U and U-B domain occupied by the P3 stars; but weargue that only a few stars could be accounted for that way. PEAGB evolution isvery rapid, and there is no progenitor population of red giants associated withP3. The result that P3 comprises young stars is consistent with inferences fromearlier HST observations of the integrated light of the cluster. Like the MilkyWay, M31 harbors a black hole closely surrounded by apparently young stars.

The Cluster of Blue Stars Surrounding the M31 Nuclear Black Hole