Globular cluster systems of massive elliptical galaxies in low-density environments with GMOS data

BASSINO, LILIA P; ENNIS, ANA I; DE BÓRTOLI, BRUNO J; CASO, JUAN PABLO

San Francisco

Workshop; Science and Evolution of Gemini Observatory; 2018

Observatorio Gemini

The aim of the present work is to disentangle the evolutionary history of massive elliptical galaxies located in low-density environments, through the characterization of their globular cluster systems (GCSs). In particular, we focus on bright ellipticals, typical of cluster environments rather than of the poor groups they inhabit, which might show signs of interaction with their neighbors. We present two photometric studies corresponding to the GCSs of NGC 6876 and NGC 3613, based on GMOS g', r', i' images obtained with Gemini South and North, respectively. Both GCSs show bimodal color distributions, i.e. with metal-poor and metal-rich globular clusters (GCs). Their most distinctive properties are:i) in NGC 6876, the GCS turned out to be more extended and much more populated (~8100 GCs) than expected, being the metal-rich GCs clearly more concentrated towards the host galaxy than metal-poor ones.ii) in NGC 3613, the projected distribution of metal-rich GCs traces the host galaxy surface-brightness distribution (i.e. its stellar population), both describing ellipses with similar eccentricity and position angle.The differences between these two systems show the important role played by the evolutionary history of galaxies in the constitution of their GCSs.