Are compact groups hostile towards faint galaxies?

ZANDIVAREZ, ARIEL; DIAZ GIMENEZ, EUGENIA; MENDES DE OLIVEIRA, CLAUDIA; GUBOLIN, HENRIQUE

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2014 vol. 572

0004-6361

Aims. The goal of this work is to understand whether the extreme environment of CGs can affect the distribution and abundance offaint galaxies around them.Methods. We performed an analysis of the faint galaxy population in the vicinity of compact and normal groups. We built a light-conemock galaxy catalogue constructed from the Millennium Run Simulation II plus a semi-analytical model of galaxy formation. Weidentified a sample of CGs in the mock catalogue as well as a control sample of normal galaxy groups and computed the projectednumber density profiles of faint galaxies around the first and the second ranked galaxies.We also compared the profiles obtained fromthe semi-analytical galaxies in CGs with those obtained from observational data. In addition, we investigated whether the ranking or the luminosity of a galaxy is the most important parameter in the determination of the centre around which the clustering of faintgalaxies occurs.Results. There is no particular influence of the extreme CG environment on the number of faint galaxies in such groups compared to control groups. When selecting normal groups with separations between the first and second ranked galaxies similar to what is observed in CGs, the faint galaxy projected number density profiles in CGs and normal groups are similar in shape and height. Weobserved a similar behaviour of the population of faint galaxies in observations and simulations in the regions closer to the first andsecond ranked galaxies. Finally, we find that the projected density of faint galaxies is higher around luminous galaxies, regardless ofthe ranking in the CG.Conclusions. The semi-analytical approach shows that CGs and their surroundings do not represent a hostile enough environment tomake faint galaxies behave differently than in normal groups.