学术文献库

This work reports the detection of a multi peaked colour pattern in the integrated colours distribution of globular clusters associated to the giant elliptical galaxy NGC 4486, using Next Generation Virgo Survey data. This feature is imprinted on the well known bimodal colour distribution of these clusters. Remarkably, the pattern is similar to that found in previous works based on photometry from the HST Advanced Camera Virgo Survey, in less massive Virgo galaxies. This characteristic can be traced up to to 45 arcmin (217 Kpc) in galactocentric radius. This suggests that globular cluster formation in Virgo has been regulated, at least partially, by a collective process composed by several discrete events, working on spatial scales comparable to the size of the galaxy cluster. Furthermore, the presence of a similar colour pattern in NGC 5128, at the outskirsts of the Virgo Super-cluster, poses an intriguing question about the spatial scale of the phenomenon. The nature of the process that leads to the colour pattern is unknown. However, energetic events connected with galaxy or sub-galaxy cluster mergers and SMBH activity, in the early Universe, appear as possible candidates to explain an eventual enhancement/quenching of the globular clusters formation, reflected in the modulation of their integrated colours. Such events, presumably, may also have had an impact on the whole star formation history in Virgo galaxies.