A montage of six stunning galaxy mergers has been released by the NASA/ESA Hubble Space Telescope to celebrate the New Year.
As part of the recent HiPEEC survey, each of these merging systems was studied to determine the rate of new star formation within such systems.
Such interactions are a central feature of the evolution of galaxies and are among the most dramatic events in a galaxy’s existence.
Galaxies undergo drastic shifts in their appearance and stellar material during unusual merger events.
These structures are excellent laboratories for following the development, under intense physical conditions, of star clusters.
Usually, the Milky Way forms star clusters with masses tens of thousands of times our Sun’s.
There is no contrast to the masses of clusters of stars forming in colliding galaxies, which can exceed the mass of our Sun millions of times over.
Such dense star systems are very luminous as well.
When the resulting galactic system enters a quieter period, even after the collision, these very large star clusters shine as long-lasting witnesses to past merger events in their host galaxy.
The Hubble Imaging Probe of Extreme Environments and Clusters (HiPEEC) survey investigated how star clusters are influenced during collisions by the rapid changes that significantly increase the rate at which new stars are produced in these galaxies by observing the six galaxy mergers shown here.
Hubble’s capabilities have made it possible to resolve large star-forming “knots” into multiple compact young star clusters. These systems have been used by Hubble’s ultraviolet and near-infrared observations to infer the age, mass, and extinction of star clusters and to examine the rate of star formation within these six merging galaxies.
The HiPEEC study shows that star cluster populations, with the most massive clusters forming towards the end of the merger process, are subject to broad and rapid variations in their properties.
Hubble has previously published each of the fusion systems seen here, as far back as 2008 and as recently as October 2020.
The Hubble Space Telescope published a series of 59 photographs of merging galaxies to mark its 18th anniversary in 2008, 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, J E Ryon, V Bajaj, A Runnholm, S Aalto, D Calzetti, J S Gallagher, M J Hayes, J M D Kruijssen, S König, S S Larsen, J Melinder, E Sabbi, L J Smith, and G Östlin, September 3, 2020, Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staa2380
The Hubble Space Telescope is a project of international collaboration between ESA and NASA.
The HiPEEC survey was performed as part of the Hubble Space Telescope program GO 14066 (PI: A.
A repository of the final data and catalogs from the survey is available in the MAST archive here.
The international team of astronomers in this study consists of A.
Adamo, K. Hollyhead, M. Messa, J.
E. Ryon, V.
Bajaj, A. Runholm, A.
Calzeti, J. S. Gallagher, M. J. Hayes, J. M.
D. Kruijssen, S. König, S. S. Larsen, J. Melinder, E. Sabbi, L. J. Smith, and G. Östlin.