Study using X-Ray telescope indicates that dark energy is uniformly distributed in space and time

When Edwin Hubble noticed distant galaxies within the Twenties, he made the groundbreaking discovery that the universe is increasing. It was not till 1998, nonetheless, that scientists observing Sort Ia supernovae additional found that the universe isn’t just increasing however has begun a phase of accelerating enlargement. “To clarify this acceleration, we’d like a supply,” says Joseph Mohr, astrophysicist at LMU. “And we check with this supply as ‘darkish vitality,’ which gives a kind of ‘anti-gravity’ to hurry up cosmic enlargement.”

Scientifically, the existence of dark energy and cosmic acceleration are a shock, and this means that our present understanding of physics is both incomplete or incorrect. The importance of the accelerating enlargement was underscored in 2011 when its discoverers acquired the Nobel Prize in Physics. “In the meantime, the character of darkish vitality has grow to be the following Nobel Prize profitable downside,” says Mohr.

Now I-Non Chiu from Nationwide Cheng Kung College in Taiwan, working in collaboration with LMU astrophysicists Matthias Klein, Sebastian Bocquet, and Joe Mohr, has revealed a primary research of darkish vitality utilizing the eROSITA X-ray telescope, which focuses on galaxy clusters. The work is revealed within the journal Month-to-month Notices of the Royal Astronomical Society.

The anti-gravity presumably brought on by darkish vitality pushes objects away from one another and suppresses the formation of huge cosmic objects that may in any other case type because of the enticing pressure of gravity. As such, darkish vitality impacts the place and the way the most important objects within the universe type—particularly, galaxy clusters with total lots starting from 10¹³ to 10¹⁵ solar lots. “We are able to study a fantastic deal concerning the nature of darkish vitality by counting the variety of galaxy clusters fashioned within the universe as a perform of time—or within the observational world as a perform of redshift,” explains Klein.

Nonetheless, galaxy clusters are extraordinarily uncommon and exhausting to seek out, requiring surveys of a big portion of the sky utilizing probably the most delicate telescopes on the planet. To this finish, the eROSITA X-ray space telescope—a challenge led by the Max Planck Institute for Extraterrestrial Physics (MPE) in Munich—was launched in 2019 to hold out an all-sky survey to seek for galaxy clusters. Within the eROSITA Ultimate Equatorial-Depth Survey (eFEDS), a mini-survey designed for efficiency verification of the following all-sky survey, about 500 galaxy clusters have been discovered. This represents one of many largest samples of low-mass galaxy clusters thus far and spans the previous 10 billion years of cosmic evolution.

Power density of darkish vitality seems to be uniform in space and fixed in time

For his or her research, Chiu and his colleagues used a further dataset on prime of the eFEDS information—optical information from the Hyper Suprime-Cam Subaru Strategic Program, which is led by the astronomical communities of Japan and Taiwan, and Princeton College. The previous LMU doctoral researcher I-Non Chiu and his LMU colleagues used this information to characterize the galaxy clusters in eFEDS and measure their lots utilizing the method of weak gravitational lensing. The mixture of the 2 datasets enabled the primary cosmological research utilizing galaxy clusters detected by eROSITA.

Their outcomes present that, by means of comparability between the info and theoretical predictions, darkish vitality makes up round 76% of total vitality density within the universe. Furthermore, the calculations indicated that the vitality density of darkish vitality seems to be uniform in space and fixed in time.

“Our outcomes additionally agree effectively with different impartial approaches, akin to earlier galaxy cluster research in addition to these utilizing weak gravitational lensing and the cosmic microwave background,” says Bocquet. “To date, all items of observational proof, together with the newest outcomes from eFEDS, counsel that darkish vitality could be described by a easy fixed, normally known as the ‘cosmological fixed.'”

“Though the present errors on the darkish vitality constraints are nonetheless bigger than we would want, this analysis employs a pattern from eFEDS that in spite of everything occupies an space lower than 1% of the complete sky,” says Mohr. This primary evaluation has thus laid a strong basis for future research of the full-sky eROSITA pattern in addition to different cluster samples.