To celebrate a new year, the NASA/THIS The Hubble Space Telescope released a montage of six stunning galaxy mergers. Each of these fusion systems was studied as part of the recent HiPEEC investigation to study the rate of new star formation in these systems. These interactions are a key aspect of the evolution of galaxies and are among the most spectacular events in the life of a galaxy.
It is during rare fusion events that galaxies undergo dramatic changes in their appearance and stellar content. These systems are excellent laboratories for tracking the formation of star clusters under extreme physical conditions.
the Milky Way generally forms star clusters whose masses are 10 thousand times the mass of our Sun. It doesn’t compare to the masses of star clusters that form in colliding galaxies, which can be millions of times the mass of our Sun.
These dense star systems are also very bright. Even after the collision, when the resulting galactic system begins to merge into a calmer phase, these very massive star clusters will shine throughout their host galaxy, as enduring witnesses to past fusion events.
By studying the six galaxy mergers presented here, the Hubble Imaging Probe of Extreme Environments and Clusters (HiPEEC) survey investigated how star clusters are affected in collisions by the rapid changes that dramatically increase the rate at which new stars form in these galaxies.
Hubble’s capabilities have made it possible to resolve large star-forming “nodes” into many young, compact star clusters. Hubble’s ultraviolet and near infrared observations from these systems were used to derive the ages, masses and extinctions of star clusters and to analyze the rate of star formation in these six molten galaxies.
The HiPEEC study reveals that the populations of star clusters undergo large and rapid variations in their properties, the most massive clusters being formed towards the end of the fusion phase.
Each of the fusion systems shown here has already been released by Hubble, as early as 2008 and as recently as October 2020. To celebrate its 18th anniversary in 2008, the Hubble Space Telescope released a collection of 59 images of molten galaxies, which can be explored here.
Reference: “Star Cluster Formation in the Most Extreme Environments: Insights from the HiPEEC Survey” by A Adamo, K Hollyhead, M Messa, JE Ryon, V Bajaj, A Runnholm, S Aalto, D Calzetti, JS Gallagher, MJ Hayes, JMD Kruijssen, S König, SS Larsen, J Melinder, E Sabbi, LJ Smith and G Östlin, September 3, 2020, Monthly notices from the Royal Astronomical Society.
DOI: 10.1093 / mnras / staa2380
The Hubble Space Telescope is an international cooperation project between ESA and NASA.
The HiPEEC survey was carried out as part of the Hubble GO 14066 space telescope program (PI: A. Adamo). A repository containing the final data and the study catalogs is available here in the MAST archives.
The international team of astronomers for this study consists of A. Adamo, K. Hollyhead, M. Messa, JE Ryon, V. Bajaj, A. Runholm, A. Aalto, D. Calzeti, JS Gallagher, MJ Hayes, JMD Kruijssen, S. König, SS Larsen, J. Melinder, E. Sabbi, LJ Smith and G. Östlin.