Globular Cluster Candidates in NGC 891
  We use deep images taken with the Advanced Camera for Surveys on board the
Hubble Space Telescope of the disk galaxy NGC 891, to search for globular
cluster candidates. This galaxy has long been considered to be a close analog
in size and structure to the Milky Way and is nearly edge-on, facilitating
studies of its halo population. These extraplanar ACS images, originally
intended to study the halo field-star populations, reach deep enough to reveal
even the faintest globular clusters that would be similar to those in the Milky
Way. From the three pointings we have identified a total of 43 candidates after
culling by object morphology, magnitude, and colour. We present (V,I)
photometry for all of these, along with measurements of their effective radius
and ellipticity. The 16 highest-rank candidates within the whole sample are
found to fall in very much the same regions of parameter space occupied by the
classic Milky Way globular clusters. Our provisional conclusion from this
survey is that the total globular cluster population in NGC 891 as a whole may
be almost as large as that of the Milky Way.
