NGC 4472 Chandra/HST study

We identify 144 X-ray point sources outside the nuclear region, 72 of which are located within the HST fields. The optical data show 1102 sources, of which 829 have colors consistent with being globular clusters (with only four in the restricted central 10" region).

Thirty matches are found between the two lists - these are likely to be low-mass X-ray binaries (LMXBs) associated with globular clusters, while ~42 of the X-ray sources have no optical counterparts to V<~25 and I<~24, indicating that they are likely to be predominantly LMXBs in the field star population with a small amount of possible contamination from background active galactic nuclei. Thus approximately 40% of the X-ray sources are in globular clusters and 4% of the globular clusters contain X-ray sources.