A Gemini/GMOS study of the bright elliptical galaxy NGC 3613 and its
  globular cluster system
  We present the first photometric study of the globular cluster system (GCS)
of the E galaxy NGC 3613 (Mv = -21.5, d = 30.1 Mpc), as well as the surface
photometry of the host galaxy, based on Gemini/GMOS images. Being considered
the central galaxy of a group, NGC 3613 inhabits a low-density environment
although its intrinsic brightness is similar to the expected one for galaxies
in the centre of clusters. The following characteristics are obtained for this
GCS. The colour distribution is bimodal, with metal-poor globular clusters
(GCs) getting slightly bluer with increasing radius. The radial and azimuthal
projected distributions show that metal-rich GCs are more concentrated towards
the host galaxy and trace its light distribution very precisely, while
metal-poor GCs present a more extended and uniform distribution. The GC
luminosity function helps validate the adopted distance. The estimated total GC
population of Ntot= 2075 +/- 130 leads to a specific frequency Sn=5.2 +/- 0.7,
a value within the expected range for GCSs with host galaxies of similar
luminosity. The surface photometry of NGC 3613 reveals a three-component
profile and a noticeable substructure. Finally, a small sample of ultra-compact
dwarf (UCD) candidates are identified in the surroundings of the host galaxy.
