Using innovative area telescopes and data sets, researchers concluded that dark energy, representing about 76% of deep spaces energy density, is evenly spread out throughout area and stays constant over time.
An initial study of dark energy utilizing eROSITA suggests that it is evenly distributed across both space and time.
Edwin Hubbles observation of remote galaxies in the 1920s led to the groundbreaking conclusion that our universe is in a state of expansion. It wasnt till 1998, however, when researchers studying Type Ia supernovae came to a stunning revelation. They discovered that the universe was not only growing, however its expansion was speeding up.
” To describe this velocity, we need a source,” says Joe Mohr, an astrophysicist at LMU. “And we describe this source as dark energy, which provides a sort of anti-gravity to speed up cosmic growth.”
Clinically, the presence of dark energy and cosmic velocity is a surprise, and this suggests that our present understanding of physics is either insufficient or incorrect. When its originators received the Nobel Prize in Physics, the significance of the accelerating expansion was underscored in 2011.
” Meanwhile, the nature of dark energy has ended up being the next Nobel Prize-winning problem,” states Mohr.
Now I-Non Chiu from National Cheng Kung University in Taiwan, operating in cooperation with LMU astrophysicists Matthias Klein, Sebastian Bocquet, and Joe Mohr, has actually released the first research study of dark energy utilizing the eROSITA X-ray telescope, which concentrates on galaxy clusters.
The anti-gravity possibly brought on by dark energy presses objects far from each other and reduces the development of big cosmic things that would otherwise form due to the appealing force of gravity. Dark energy affects where and how the largest things in the universe type– particularly, galaxy clusters with total masses varying from 1013 to 1015 solar masses.
” We can learn a terrific offer about the nature of dark energy by counting the variety of galaxy clusters formed in the universe as a function of time– or in the observational world as a function of redshift,” describes Klein.
Galaxy clusters are incredibly uncommon and tough to discover, needing surveys of a large part of the sky using the most sensitive telescopes in the world. To this end, the eROSITA X-ray space telescope– a job led by the Max Planck Institute for Extraterrestrial Physics (MPE) in Munich– was released in 2019 to perform an all-sky study to look for galaxy clusters.
In the eROSITA Final Equatorial-Depth Survey (eFEDS), a mini-survey designed for performance confirmation of the subsequent all-sky survey, about 500 galaxy clusters were found. This represents one of the largest samples of low-mass galaxy clusters to date and covers the past 10 billion years of cosmic development.
For their research study, Chiu and his coworkers utilized an additional dataset on top of the eFEDS data– optical data from the Hyper Suprime-Cam Subaru Strategic Program, which is led by the huge communities of Japan and Taiwan, and Princeton University.
The former LMU doctoral researcher I-Non Chiu and his LMU coworkers utilized this data to define the galaxy clusters in eFEDS and measure their masses using the procedure of weak gravitational lensing. The mix of the 2 datasets enabled the very first cosmological research study using galaxy clusters found by eROSITA.
Their outcomes show that, through comparison between the data and theoretical predictions, dark energy comprises around 76% of the overall energy density in the universe. Moreover, the estimations showed that the energy density of dark energy seems uniform in area and constant in time.
” Our results likewise agree well with other independent approaches, such as previous galaxy cluster studies as well as those utilizing weak gravitational lensing and the cosmic microwave background,” says Bocquet. Up until now, all pieces of observational proof, including the current outcomes from eFEDS, suggest that dark energy can be described by a basic continuous, generally referred to as the cosmological constant.
” Although the present mistakes on the dark energy restraints are still bigger than we would want, this research utilizes a sample from eFEDS that after all inhabits a location less than 1% of the full sky,” says Mohr. This first analysis has hence laid a solid foundation for future studies of the full-sky eROSITA sample as well as other cluster samples.
Recommendation: “Cosmological constraints from galaxy clusters and groups in the eROSITA last equatorial depth study” by I-Non Chiu, Matthias Klein, Joseph Mohr and Sebastian Bocquet, 21 April 2023, Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/ mnras/stad957.
