The bright arcs between 12 and 3 o'clock are the Sunburst Galaxy. A fainter counter-image is seen between 7 o'clock and 9 o'clock.[1] Credit:ESA/Hubble, NASA, Rivera-Thorsen et al.
The Sunburst galaxy is a strongly magnified galaxy at redshift z=2.38 (10.9 billion light years) behind the galaxy cluster PSZ1 G311.65-18.48.[2]
The cluster acts as a power magnifier thanks to the gravitational lensing effect. The galaxy cluster distorts the space around it creating different paths for the photons coming from the Sunburst galaxy. This lensing creates four arc segment roughly following a circle around the foreground lensing cluster. Chance alignments of the Sunburst Galaxy and galaxies in the lensing cluster breaks up some of the arc segments into multiple smaller images, creating a total of 12 full or partial images of the galaxy along the arc; some of these images are magnified by very large factors.[1][3] In one of these strongly magnified images of the Sunburst galaxy, astronomers have identified the most luminous star known to date, Godzilla.[3][4] However, another study suggests that Godzilla is a young massive star cluster consists of thousands of bright stars[5].
The Sunburst galaxy hosts a massive star cluster that is only 2--4 Myr[6][7] after formation. The star cluster is very compact, weighing tens of millions of solar masses while having a radius no larger than 10 parsecs[8][7]. The star cluster is seen to be leaking ionizing radiation into the intergalactic space[2]. In its vicinity, the star cluster excites a dense nebula that is enriched with nitrogen and is likely to have condensed from massive star wind material[7].
^Pascale, M.; Dai, L. (2024). "A Young Super Star Cluster Powering a Nebula of Retained Massive Star Ejecta". arXiv:2404.10755 [astro-ph.GA].
^Chisholm, J.; Rigby, J.; Bayliss, M.; Berg, D.A.; Dahle, H.; Gladders, M.; Sharon, K. (2019). "Constraining the Metallicities, Ages, Star Formation Histories, and Ionizing Continua of Extragalactic Massive Star Populations". Astrophysical Journal. 882: 31. arXiv:1905.04314. Bibcode:2019ApJ...882..182C. doi:10.3847/1538-4357/ab3104.{{cite journal}}: CS1 maint: unflagged free DOI (link)
