We present a study of the globular cluster systems of two edge–on spiral galaxies , NGC 4565 and NGC 5907 , from WFPC2 images in the F450W and F814W filters .
The globular cluster systems of both galaxies appear to be similar to the Galactic globular cluster system .
In particular , we derive total numbers of globular clusters of N _ { GC } ( 4565 ) = 204 \pm 38 ^ { +87 } _ { -53 } and N _ { GC } ( 5907 ) = 170 \pm 41 ^ { +47 } _ { -72 } ( where the first are statistical , the second potential systematic errors ) for NGC 4565 and NGC 5907 , respectively .
This determination is based on a comparison to the Milky Way system , for which we adopt a total number of globular clusters of 180 \pm 20 .
The specific frequency of both galaxies is S _ { N } \simeq 0.6 : indistinguishable from the value for the Milky Way .
The similarity in the globular cluster systems of the two galaxies is noteworthy since they have significantly different thick disks and bulge-to-disk ratios .
This would suggest that these two components do not play a major role in the building up of a globular cluster system around late–type galaxies .