The glow within the cluster is the soft luminosity of stars that have been stripped from their galaxy amidst the layers of galaxy clusters.
Abell 3667 is depicted in this Decam image. Image credits: CTIO/NOIRLAB/NSF/AURA/ANTHONY ENGLERT, Brown University/TA Rector, Noirlab/M. Zamani & D of University of Alaska Anchorage & NSF. De Martin, NSF’s Noirlab.
Galaxy clusters comprise thousands of galaxies, varying widely in age, shape, and size.
Typically, they have a mass about 10 billion times that of the Sun.
Historically, galactic clusters were regarded as the largest structures in the universe, spanning hundreds of millions of light-years and including numerous galactic clusters and groups, until superclusters were discovered in the 1980s.
Nonetheless, galaxy clusters still hold the title of the largest gravitationally bound structure in the universe.
“The study of galaxy clusters not only informs us about the formation of the universe, but it also places constraints on the characteristics of dark matter,” stated Brown University astronomer Anthony Englat and his team.
One significant clue astronomers seek to grasp the history of galactic clusters is the light within the cluster. This faint glow is emitted by stars that have been stripped from their original galaxy due to the immense gravitational forces of the forming galaxy cluster.
These stars provide evidence of past galactic interactions, although most current telescopes and cameras face challenges in detecting them.
The subtle intra-cluster light from the galaxy cluster Abel 3667 shines vividly in new images created from a total of 28 hours of observation at 570 megapixels using the Dark Energy Camera (Decam) at NSF’s M. Blanco 4-M Telescope, a program of NSF’s Noirlab at Cerro Tololo Inter-American Observatory.
“Abell 3667 is located over 700 million light-years away from us,” the astronomer mentioned.
“Most of the faint light sources in this image are distant galaxies, not foreground stars from our own Milky Way.”
“In Abell 3667, two small galaxy clusters are currently merging, as evidenced by the luminous bridge (yellow) of stars extending toward the center of this image.”
“This bridge is formed from material stripped off from the merging galaxies, forming one massive conglomerate known as the brightest cluster galaxy.”
“Not only does this sparkling sky encompass distant galaxies, but it also highlights faint foreground features due to the prolonged exposure.”
“The Milky Way’s hair follicles, or integrated flux nebula, consist of faint clouds of interstellar dust that appear as soft bluish chains crossing the image.”
“These structures are patches of dust that are illuminated by the light of the stars within our own galaxy.”
“They present as diffuse, filamentous formations that can span extensive areas of the sky.”
Survey results will be published in the Astrophysics Journal Letter.
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Anthony M. Engrat et al. 2025. Announcing optical bridges in Abel 3667 in-cluster light: LSST precursor data. apjl 989, L2; doi: 10.3847/2041-8213/ade8f1
Source: www.sci.news
