We present the first photometric study of the globular cluster system ( GCS ) of the E galaxy NGC 3613 ( M _ { V } = -21.5 , d \sim 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 N _ { tot } = 2075 \pm 130 leads to a specific frequency S _ { N } = 5.2 \pm 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 .