Free Astronomy Magazine May-June 2021

49 MAY-JUNE 2021 ASTRO PUBLISHING star clusters will shine throughout their host galaxy, as long-lasting wit- nesses of past merging events. By studying the six galaxy mergers shown here, the Hubble imaging Probe of Extreme Environments and Clusters (HiPEEC) survey has investi- gated how star clusters are affected during collisions by the rapid changes that drastically increase the rate at which new stars are formed in these galaxies. Hubble’s capabilities have made it possible to resolve large star-forming “knots” into numerous compact young star clusters. Hub- ble’s ultraviolet and near-infrared observations of these systems have been used to derive star cluster ages, masses, and extinctions and to an- alyse the star formation rate within these six merging galaxies. The HiPEEC study reveals that the star cluster populations undergo large and rapid variations in their properties, with the most massive clusters formed towards the end of the merger phase. NGC 34 NGC 4194 [NASA & ESA] !