Scientists using data from the Atacama Cosmology telescope in Chile have drawn up a detailed map of the distribution of dark matter over a quarter of the sky.
The map shows regions whose mass distribution extends essentially as far as we can see in time; he uses the cosmic background of microwaves as a backdrop for the portrait of dark matter. The team’s research will be presented at Future Science with CMB x LSS conference in Kyoto, Japan.
“We’ve mapped invisible dark matter across the sky to the greatest distances, and clearly see features of this invisible world that span hundreds of millions of light-years,” said cosmologist Blake Sherwin. Cambridge University, at Princeton University release. “It looks like what our theories predict.”
Dark matter is a catch-all term for what makes up about 27% of the universe, but it is not directly observable. We only know that it is there, whatever it is, because of its gravitational effects.
People probe dark matter through two main approaches: ground-based experiments and deep observations of the cosmos. There is many experiments that attempt to identify dark matter amid a sea of proposed dark matter candidates, which include axions and weakly interacting massive particles (WIMP).
But the only way to observe dark matter is indirectly, in the way its gravitational effects are observed at large scales. Enter the Atacama Cosmology Telescope, which more precisely dated the universe in 2021. The telescope map is based on a matter map of the universe released earlier this year, which was produced using data from the Dark Energy Survey and the South Pole Telescope. This map confirmed previous estimates of the ratio of ordinary matter to dark matter and revealed that the distribution of matter was less clumped than previously thought.
The new map addresses a lingering concern from Einstein’s general relativity: how the most massive objects in the universe, like supermassive black holes, bend light from more distant sources. One of these sources is the cosmic microwave backgroundoldest detectable light, which radiates in the aftermath of the Big Bang.
The researchers effectively used the background as a backlight, to illuminate the higher density regions of the universe.
“It’s kind of like a silhouette, but instead of just having black in the silhouette, you have texture and bits of dark matter, like light coming through a fabric curtain that had a lot of knots in it. and bumps,” said Suzanne Staggs. , director of the Atacama Cosmology Telescope and physicist at Princeton, in the university statement.
“The famous blue and yellow CMB image is a snapshot of what the universe looked like at a single epoch, around 13 billion years ago, and now it gives us information about all epochs since,” said added Staggs.
The recent analysis suggests dark matter was lumpy enough to fit the Standard Model of cosmology, which is based on Einstein’s theory of gravity.
Eric Baxter, an astronomer at the University of Hawaii and co-author of the research that resulted in February’s dark matter map, told Gizmodo in an email that his team’s map was sensitive to lows. redshifts (i.e. nearby, in the newer universe). On the other hand, the new map focuses exclusively on the lens of the cosmic microwave background, which means higher redshifts and a larger scale.
“In other words, our measurements and the new ACT measurements are probing somewhat different (and complementary) aspects of the distribution of matter,” Baxter said. “So rather than contradicting our previous results, the new results may provide an important new piece of the puzzle about possible discrepancies with our standard cosmological model.”
“Perhaps the Universe is less lumpy than expected on small scales and in recent times (i.e. the regime probed by our analysis), but is consistent with expectations at earlier and larger times. scale,” Baxter added.
New instruments should help unravel the distribution of matter in the universe. An upcoming telescope at the Simons Observatory in the Atacama is expected to begin operations in 2024 and will map the sky nearly 10 times faster than the Atacama Cosmological Telescope, according to the Exit from Princeton.
With the the greatest digital camera ever built which is to be installed at the Vera Rubin Observatory, also in the Atacama, this is an exciting time for terrestrial observatories.
More: New Dark Matter Theory Says a ‘Black Big Bang’ Created the Hidden Universe
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