A Gemini/GMOS study of the bright elliptical galaxy NGC 3613 and its globular cluster system

DE BÓRTOLI B.; BASSINO L.; CASO J.P.; ENNIS A.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 492 p. 4313 - 4324

0035-8711

We present the first photometric study of the globular cluster system (GCS) of the Egalaxy NGC 3613 (MV=−21.5, d∼30.1Mpc), as well as the surface photometry of thehost galaxy, based on Gemini/GMOS images. Being considered the central galaxy ofa group, NGC 3613 inhabits a low-density environment although its intrinsic bright-ness is similar to the expected one for galaxies in the centre of clusters. The followingcharacteristics are obtained for this GCS. The colour distribution is bimodal, withmetal-poor globular clusters (GCs) getting slightly bluer with increasing radius. Theradial and azimuthal projected distributions show that metal-rich GCs are more con-centrated towards the host galaxy and trace its light distribution very precisely, whilemetal-poor GCs present a more extended and uniform distribution. The GC luminos-ity function helps validate the adopted distance. The estimated total GC populationofNtot=2075±130leads to a specific frequencySN=5.2±0.7, a value within theexpected range for GCSs with host galaxies of similar luminosity. The surface pho-tometry 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