Researchers have assembled hundreds of astronomical observations into a high-definition image of the cosmic filament, part of the megastructure that underlies the matter of the Universe.
The filament connects two galaxies that date back to when the Universe was 2 billion years old (it is now about 13.77 billion years old). It demonstrates how a huge but hidden part of the Universe affects the shape of the structures we see, such as ancient galaxies. The team’s study describing the image was published late last month in the journal Nature Astronomy.
“By capturing the faint light emitted by this filament, which traveled to Earth in just under 12 billion years, we were able to characterize its shape precisely,” said Davide Tornotti, a doctoral student at the University of Milano-Bicocca and lead author of the study, in a release from the Max Planck Institute for Astrophysics. “For the first time, we have been able to trace the boundary between the gas found in galaxies and the matter found in the cosmic web using direct measurements.”
The distribution of matter in the early Universe was much more uniform than today, when dense clusters of matter are interspersed in space in the form of black holes, galaxies, etc. Over time, this uniform distribution of matter shifted to regions of higher density, stretching across the universe like daisy chains – cosmic threads connecting these clusters of galaxies. Some cosmic filaments are even larger than the 3 million light-year-long structure that the recent team explored; for example, the Hubble Space Telescope previously spotted a 13 million light-year-long filament.
The researchers took the image using the Multi-Unit Spectroscopic Explorer, or MUSE, spectrograph mounted on the Very Large Telescope of the European Southern Observatory. The Very Large Telescope is located at ESO’s Paranal Observatory in Chile’s Atacama Desert and is currently under threat (somewhat ironically) due to plans to build a green energy project in the desert. Scientists and ESO administrators are lamenting this plan, which they say will seriously pollute one of the world’s cleanest skies for ground-based astronomy.
The data collection for the latest image took hundreds of hours, providing a detailed view of the filament morphology and density of the structures, as predicted by the leading model of the Universe’s dark matter.
The Cosmic Web is the ultra-scale structure of the Universe; it encompasses everything from the shape and orientation of galaxies to the way mass is distributed in the Universe. This mass necessarily includes Dark Matter, or approximately 27% of the matter in the Universe, which scientists know exists but cannot observe directly because it has little or no interaction with ordinary matter. Dark matter can only be observed indirectly through its gravitational interaction with matter.
The structure of the cosmic web will become clearer thanks to the data from the Euclid space telescope. Euclid’s mission is to decipher the secrets of dark matter and dark energy and to assemble an atlas of space – the largest 3D map of our Universe in history. In October, ESA scientists released the first part of this atlas, a 208-gigapixel image covering 14 million galaxies.
“As they say in Bavaria: “Eine ist keine” – one doesn’t count,” said Fabrizio Arrigoni Battaglia, a researcher at the Planck Institute, in the same release. “We are therefore collecting additional data to detect more of these structures, with the ultimate goal of gaining a complete picture of how gas is distributed and flows in the cosmic web.”
Indeed, if more images are as detailed and provide as much information about the nature of space, not only scientists but also the space-loving public will benefit.
