A Normal Abundance of Faint Satellites in the Fossil Group NGC 6482

Abstract

Fossil groups are considered the end product in a galaxy group's evolution -- a massive central galaxy that dominates the luminosity budget of the group, as the outcome of efficient merging between intermediate-luminosity members. Little is however known about the faint satellite systems of fossil groups. Here we present a SUBARU/Suprime-Cam wide-field, deep imaging study in the B- and R-band of the nearest fossil group NGC 6482 (M_{tot}\sim4\times10^{12}M_{\sun}), covering the virial radius out to 310 kpc. We perform detailed completeness estimations and select group member candidates by a combination of automated object detection and visual inspection. A fiducial sample of 48 member candidates down to M_R -10.5 mag is detected, making this study the deepest of a fossil group up to now. We investigate the photometric scaling relations, the colour-magnitude relation, and the luminosity function of our galaxy sample. We find evidence of recent and ongoing merger events among bright group galaxies. The colour-magnitude relation is comparable to that of nearby galaxy clusters, and exhibits significant scatter at the faintest luminosities. The completeness-corrected luminosity function is dominated by early-type dwarfs and is characterized by a faint end slope α=-1.32\pm0.05. We conclude that the NGC 6482 fossil group shows photometric properties consistent with those of regular galaxy clusters and groups, including a normal abundance of faint satellites.

15 pages, 14 figures, A&A accepted

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Cited by in corpus (10)

• The Next Generation Virgo Cluster Survey (NGVS). XIII. The Luminosity and Mass Function of Galaxies in the Core of the Virgo Cluster and the Contribution from Disrupted Satellites
• Ultimate age-dating method for galaxy groups; clues from the Millennium Simulations
• Fossil group origins V. The dependence of the luminosity function on the magnitude gap
• Fossil Group Origins VII. Galaxy substructures in fossil systems
• Fossil groups in the Millennium simulation. From the brightest to the faintest galaxies during the past 8 Gyr
• Fossil group origins IX. Probing the formation of fossil galaxy groups with stellar population gradients of their central galaxies
• The Unusually High Halo Concentration of the Fossil Group NGC 6482: Evidence for Weak Adiabatic Contraction
• Using Strong Gravitational Lensing to Identify Fossil Group Progenitors
• Fossil group origins XII. Large-scale environment around fossil systems
• Fossil group origins: VIII RXJ075243.6+455653 a transitionary fossil group