Intergalactic globular clusters and the faint end of the galaxy number counts in A1656 (Coma)

Abstract

The existence of an intergalactic globular cluster population in the Coma cluster of galaxies has been tested using surface-brightness fluctuations. The main result is that the intergalactic globular cluster surface density ($N_{\mathrm{IGC}}$) does not correlate with the distance to the center of Coma and hence with the environment. Furthermore, comparing these results with different Coma mass-distribution model predictions, it is suggested that $N_{\mathrm{IGC}}$ must in fact be zero all over Coma. On the other hand, the results for $N_{\mathrm{IGC}}$ and the faint end of the galaxy number counts (beyond $m_R=23.5$) are connected. So $N_{\mathrm{IGC}}=0$ settles the slope of this function, which turns out to be $\gamma =0.36\pm 0.01$ down to $m_R=26.5$. The fact that $N_{\mathrm{IGC}}=0$ all over Coma suggests that globular clusters were formed only, or almost only, from protogalactic clouds. None, or perhaps very few, could have formed in isolated regions. It also seems inappropriate to advocate a relationship between intergalactic globular clusters and dark matter distributions, although it is true that the relationship could still exist but not be strong enough to have been detected. Finally, since our conclusion is that intergalactic globular clusters do not exist in Coma, accretion of intergalactic globular clusters might not be significant in galaxy formation and evolutionary processes in the Coma galaxies.

23 pages, 5 figures, accepted for publication in ApJ

References in corpus (4)

• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• Dynamics of the Globular Cluster System Associated with M87 (NGC 4486). II. Analysis
• Globular cluster systems in elliptical galaxies of Coma
• Galaxy Associations within the Coma Cluster

Cited by in corpus (10)

• The HST/ACS Coma Cluster Survey IV. Intergalactic Globular Clusters and the Massive Globular Cluster System at the Core of the Coma Galaxy Cluster
• Diffuse Optical Light in Galaxy Clusters I: Abell 3888
• Detection of a Large Scale Structure of Intracluster Globular Clusters in the Virgo Cluster
• Virgo's Intracluster Globular Clusters as Seen by the Advanced Camera for Surveys
• A Subaru/Suprime-Cam wide-field survey of globular cluster populations around M87 - II: Colour and spatial distribution
• Spatial variations of the optical galaxy luminosity functions and red sequences in the Coma cluster: clues to its assembly history
• On spatial distributions of old globular clusters in clusters of galaxies
• Formation of intracluster globular clusters
• Triggering the Formation of Halo Globular Clusters with Galaxy Outflows
• Beyond the Hubble Deep Field Limiting Magnitude: Faint Galaxy Number Counts from Surface-Brightness Fluctuations