Webb identifies the earliest strands of the cosmic web (annotated)

Galaxies are not scattered randomly across the universe. They gather together not only into clusters, but into vast interconnected filamentary structures with gigantic barren voids in between. This “cosmic web” started out tenuous and became more distinct over time as gravity drew matter together.

Astronomers for the ASPIRE program using the NASA/ESA/CSA James Webb Space Telescope have discovered a thread-like arrangement of 10 galaxies that existed just 830 million years after the Big Bang. This deep galaxy field from Webb’s NIRCam (Near-Infrared Camera) shows an arrangement of these 10 distant galaxies marked by eight white circles in a diagonal, thread-like line. (Two of the circles contain more than one galaxy.) This 3 million light-year-long filament is anchored by a very distant and luminous quasar – a galaxy with an active, supermassive black hole at its core. The quasar, called J0305-3150, appears in the middle of the cluster of three circles on the right side of the image. Its brightness outshines its host galaxy. The 10 marked galaxies existed just 830 million years after the big bang. The team believes the filament will eventually evolve into a massive cluster of galaxies.

These results were published in two papers in The Astrophysical Journal Letters on 29 June 2023.

[Image description: Hundreds of tiny galaxies appear across the black expanse of space. The galaxy colours vary. Most galaxies are so distant they appear as single points of light. Ten galaxies are denoted with eight white circles in a diagonal, thread-like line. This line is anchored by a bright quasar, called J0305-3150, whose brightness outshines its host galaxy.]

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