Suspected globular clusters in the Fornax I cluster of galaxies

Abstract

HERE we report the existence of a significant clustering of faint objects around three galaxies in the Fornax I cluster of galaxies. The nature of these objects is uncertain, although on the scant evidence available, we believe at least some of them to be unresolved globular clusters. We base our claim on the examination of a single, direct photographic plate taken by Dr R. D. Cannon at the prime focus of the Anglo–Australian telescope on the night of January 18, 1975. The plate, AAT609, is an unsensitised IIaO, exposed for 20 min through a GG 385 filter, and covers an area of 1° × 1° centred on RA 3 h 36 min, dec. −35.5° (1950.0). The smallest images on the plate are slightly elliptical, owing to slight trailing in RA, and have dimensions 1.5″ × 2.0″. In the course of assigning morphological types to the brightest galaxies in the field, we found a noticeable increase in the number of faint objects in the vicinity of the galaxies NGC1374, NGC1379 and NGC1399. These three galaxies are all elliptical and are among the nine brightest on the plate. Of the remaining six bright galaxies, two (NGC1389 and NGC1404) are elliptical and four (NGC1375, NGC1380, NGC1381 and NGC1387) are lenticular; none of these six galaxies exhibits any significant enhancement in the number of adjacent field objects.