Dark Energy Survey (DES) research has confirmed the existence of a supervacuum, an unusually large region with a lower-than-average material density, in the constellation Eridan. Her study may provide new clues to understanding the nature of dark energy. The results were published on December 17, 2021 in the Monthly Notices of the Royal Astronomical Society.
The ability to map the largest structures in the universe has long been the aspiration of astrophysicists. After meticulously mapping our cosmic backyard, recent discoveries have put our place galaxy w Supercluster LaniakeaAs part of the cosmic web of galaxies. However, not much is known about our cosmic neighborhood.
This area is also the site of the so-called cold spot, which is one of the large-scale anomalies microwave background radiation (CMB), a type of fossil radiation from the beginning of the universe. This anomaly corresponds to a structure located over the Southern Hemisphere at a temperature below average.
However, a cold spot the size of a cold spot seems very unlikely, according to Standard Cosmic Model. The DES team had a hypothesis that a supervacuum could, at least in part, explain why this point is so much larger and cooler than expected. In particular, cosmologists can use this huge degree as a unique laboratory to find out what is elusive dark energy.
In terms of energy, the supervacuum is best imagined as a hill that the cosmic background radiation photons must climb on their journey toward our telescopes. As they enter, they must invest energy to pass through the lower densities. However, during their journey, these photons are subject to the action of dark energy responsible for the cosmic expansion. Dark energy acts as a driving force, and is the opposite of gravity, thus slowing down and refreshing the rate of formation of the largest cosmic structures.
So, coming out of the supervacuum, the CMB photons, rather than recovering that energy invested in climbing the hill, lose some of it, because dark energy reduces falls. The resulting energy loss is compensated for by a slight cooling to the temperature of the CMB photons crossing the supervacuum. By studying this effect in detail, cosmologists can make conclusions about the properties of dark energy.
In the case of this cold spot, this hypothesis is already supported by research galaxiesBut the DES data provides key new observational data. The reconstructed map of dark energy distribution provides statistically strong evidence for a loss of about 1.8 billion diameters light years In the constellation Eridanus, which corresponds to the structure prevailing in our cosmic neighborhood.
However, the observed dimensions of the Eridan supervacuum cannot fully explain the profound dip in cold point temperature if we take the standard dark energy model into our calculations. András Kovács of Astrofísica de Canarias (IAC) explains. According to the astrophysicist, a full explanation would require a more powerful component of dark energy, which could cause a faster expansion and a less compact universe in later times.
The possible positive is that hundreds of other supervacuums, discovered in a farther universe, have also shown moderate evidence for stronger-than-expected cold spots, but it is likely that the solution to this long-running controversy in cosmology will come from the next generation of cosmological research That will map to larger sizes – concludes the researcher.
Pictured: the dome of the Blanco Telescope at the Cerro Tololo Pan-American Observatory, where the DES dark energy camera is installed. Source: Reidar Hahn / Fermilab