Title: Detection of the Stellar Intracluster Medium in Perseus (Abell 426),
Abstract: Hubble Space Telescope photometry from the ACS/WFC and WFPC2 cameras is used
to detect and measure globular clusters (GCs) in the central region of the rich
Perseus cluster of galaxies. A detectable population of Intragalactic GCs is
found extending out to at least 500 kpc from the cluster center. These objects
display luminosity and color (metallicity) distributions that are entirely
normal for GC populations. Extrapolating from the limited spatial coverage of
the HST fields, we estimate very roughly that the entire Perseus cluster should
contain ~50000 or more IGCs, but a targetted wide-field survey will be needed
for a more definitive answer. Separate brief results are presented for the rich
GC systems in NGC 1272 and NGC 1275, the two largest Perseus ellipticals. For
NGC 1272 we find a specific frequency S_N = 8, while for the central giant NGC
1275, S_N ~ 12. In both these giant galaxies, the GC colors are well matched by
bimodal distributions, with the majority in the blue (metal-poor) component.
This preliminary study suggests that Perseus is a prime target for a more
comprehensive deep imaging survey of Intragalactic GCs.