Astronomy & Space

Dark energy is uniformly spread in space and time, according to research utilizing an X-ray telescope.

At the point when Edwin Hubble noticed far-off cosmic systems during the 1920s, he made the historic revelation that the universe was growing. However, it wasn’t until 1998 that researchers who were observing Type Ia supernovae made further discoveries, which revealed that the universe is not only expanding but has also begun a phase of expanding at a faster rate. To make sense of this speed increase, we want a source,” says Joseph Mohr, an astrophysicist at LMU. “What’s more, we allude to this source as ‘dull energy,’ which gives a kind of ‘repulsive force’ to accelerate vast extension.”

Dark energy and cosmic acceleration are scientifically surprising, indicating that our current understanding of physics is either incorrect or incomplete. The meaning of speeding up development was highlighted in 2011 when its pioneers won the Nobel Prize in Material Science. “In the interim, the idea of dull energy has turned into the following Nobel Prize-winning issue,” says Mohr.

Presently, I-Non Chiu from Public Cheng Kung College in Taiwan, working as a team with LMU astrophysicists Matthias Klein, Sebastian Bocquet, and Joe Mohr, has distributed a first investigation of dull energy utilizing the eROSITA X-beam telescope, which centers around system bunches. The work has been published in the Royal Astronomical Society journal Monthly Notices.

“We need a source to explain this acceleration. And we call this source ‘dark energy’ because it acts as a type of ‘anti-gravity,’ accelerating cosmic expansion.”

Joseph Mohr, astrophysicist at LMU.

Large cosmic objects that would otherwise form due to the attraction of gravity are prevented from forming due to anti-gravity, which may be caused by dark energy. In that capacity, dull energy influences where and how the biggest articles known to mankind structure — specifically, system groups with absolute masses going from 1013 to 1015 sun-based masses. ” “Counting the number of galaxy clusters formed in the universe as a function of time or in the observational world as a function of redshift can reveal a lot about the nature of dark energy,” says Klein.

Galaxy clusters, on the other hand, are extremely uncommon and difficult to locate, necessitating extensive sky surveys with the world’s most sensitive telescopes. To this end, the eROSITA X-beam space telescope — an undertaking driven by the Maximum Planck Establishment for Extraterrestrial Physical Science (MPE) in Munich — was sent off in 2019 to do an all-sky overview to look for system groups. About 500 galaxy clusters were discovered in the eROSITA Final Equatorial-Depth Survey (eFEDS), a mini-survey meant to check the all-sky survey’s performance. This covers the past 10 billion years of cosmic evolution and is one of the largest samples of low-mass galaxy clusters ever collected.

In addition to the eFEDS data, Chiu and his colleagues used optical data from the Hyper Suprime-Cam Subaru Strategic Program, which is led by the astronomical communities of Japan, Taiwan, and Princeton University. The energy density of dark energy appears to be uniform across space and constant over time. This data was used by I-Non Chiu, a former doctoral researcher at LMU, and his colleagues at LMU to characterize the galaxy clusters in eFEDS and measure their masses using weak gravitational lensing. The first cosmological study that made use of eROSITA-detected galaxy clusters was made possible by combining the two datasets.

Through comparison of the data and theoretical predictions, their findings demonstrate that dark energy accounts for approximately 76% of the universe’s total energy density. Additionally, the calculations suggested that the energy density of dark energy appears to be constant throughout time and space.

Bocquet states, “Our results also agree well with other independent approaches, like previous galaxy cluster studies, those using weak gravitational lensing, and the cosmic microwave background.” “Dark energy can be described by a simple constant, commonly referred to as the ‘cosmological constant,’ according to all observational evidence to this point, including the most recent eFEDS findings.”

“This research employs a sample from eFEDS that, after all, occupies an area less than 1% of the full sky,” states Mohr, “even though the current errors on the dark energy constraints are still larger than we would wish.” As a result, this initial analysis provides a solid foundation for subsequent research on the full-sky eROSITA sample and other cluster samples.

More information: I-Non Chiu et al, Cosmological constraints from galaxy clusters and groups in the eROSITA final equatorial depth survey, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad957

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