画期的な新しい暗黒物質マップは、アインシュタインの一般相対性理論を検証します

Atacama Cosmology Telescope の共同研究は、宇宙の進化を理解する上で大きなブレークスルーをもたらしました。

何千年もの間、人類は宇宙の神秘に魅了されてきました。

宇宙の起源を想像した古代の哲学者とは異なり、現代の宇宙論者は定量的なツールを使用して、宇宙の進化と構造に関する洞察を得ています。 現代の宇宙論は、アルバート アインシュタインの一般相対性理論の発展とともに、20 世紀初頭にまでさかのぼります。

現在、Atacama Cosmology Telescope (ACT) Collaboration の研究者が一連の論文を の[{” attribute=””>Astrophysical Journal featuring a groundbreaking new map of dark matter distributed across a quarter of the sky, extending deep into the cosmos, that confirms Einstein’s theory of how massive structures grow and bend light over the 14-billion-year life span of the universe.

The new map uses light from the cosmic microwave background (CMB) essentially as a backlight to silhouette all the matter between us and the Big Bang.

The Atacama Cosmology Telescope in Northern Chile, supported by the National Science Foundation, operated from 2007-2022. The project is led by Princeton University and the University of Pennsylvania — Director Suzanne Staggs at Princeton, Deputy Director Mark Devlin at Penn — with 160 collaborators at 47 institutions. Credit: Mark Devlin, Deputy Director of the Atacama Cosmology Telescope and the Reese Flower Professor of Astronomy at the University of Pennsylvania

“It’s a bit like silhouetting, but instead of just having black in the silhouette, you have texture and lumps of dark matter, as if the light were streaming through a fabric curtain that had lots of knots and bumps in it,” said Suzanne Staggs, director of ACT and Henry DeWolf Smyth Professor of Physics at Princeton University. “The famous blue and yellow CMB image [from 2003] これは、約 130 億年前のある時代の宇宙のスナップショットであり、それ以降のすべての時代に関する情報を提供してくれます。」

「目に見えないものを見ることができ、目に見える星空の銀河を支えている暗黒物質の足場を明らかにすることはエキサイティングです」と、分析を主導する物理学および天体物理学の教授であるジョー・ダンクリーはACTに語った. 「この新しい画像では、銀河を取り囲み、接続している暗黒物質の目に見えない宇宙網を直接見ることができます。」

「通常、天文学者は光しか測定できないため、銀河が宇宙全体にどのように分布しているかがわかります。これらの観測は質量の分布を明らかにするため、主に暗黒物質が宇宙全体にどのように分布しているかを示しています」と天文学の教授であるデビッド・シュパーゲルは言います。プリンストン大学、チャールズ a. .

Atacama Cosmology Telescope の協力による研究は、全天の 4 分の 1 にまたがり、宇宙の奥深くまで到達する、画期的な新しい暗黒物質のマップで最高潮に達しました。 この結果は、1世紀以上にわたって宇宙論の標準モデルの基礎となってきたアインシュタインの一般相対性理論をさらに支持し、暗黒物質を解明する新しい方法を提供します。 クレジット: Lucy Reading-Ikkanda、シモンズ財団

「私たちは空全体の目に見えない暗黒物質の分布をマッピングしましたが、それはまさに私たちの理論で予測された通りです」と共著者のブレイク・シャーウィン博士、2013年は述べています. プリンストン大学を卒業し、ケンブリッジ大学で宇宙論の教授を務め、ACT 研究者の大規模なグループを率いています。 「これは、何十億年にもわたって私たちの宇宙で構造がどのように形成されたかという話を私たちが理解しているという驚くべき証拠です。[{” attribute=””>Big Bang to today.’

He added: “Remarkably, 80% of the mass in the universe is invisible. By mapping the dark matter distribution across the sky to the largest distances, our ACT lensing measurements allow us to clearly see this invisible world.”

“When we proposed this experiment in 2003, we had no idea the full extent of information that could be extracted from our telescope,” said Mark Devlin, the Reese Flower Professor of Astronomy at the University of Pennsylvania and the deputy director of ACT, who was a Princeton postdoc from 1994-1995. “We owe this to the cleverness of the theorists, the many people who built new instruments to make our telescope more sensitive, and the new analysis techniques our team came up with.” This includes a sophisticated new model of ACT’s instrument noise by Princeton graduate student Zach Atkins.

Research by the Atacama Cosmology Telescope collaboration has culminated in a groundbreaking new map of dark matter distributed across a quarter of the entire sky, reaching deep into the cosmos. Findings provide further support to Einstein’s theory of general relativity, which has been the foundation of the standard model of cosmology for more than a century, and offer new methods to demystify dark matter. Credit: Image courtesy of Debra Kellner

Despite making up most of the universe, dark matter has been hard to detect because it doesn’t interact with light or other forms of electromagnetic radiation. As far as we know, dark matter only interacts with gravity.

To track it down, the more than 160 collaborators who have built and gathered data from the National Science Foundation’s Atacama Cosmology Telescope in the high Chilean Andes observed light emanating following the dawn of the universe’s formation, the Big Bang — when the universe was only 380,000 years old. Cosmologists often refer to this diffuse CMB light that fills our entire universe as the “baby picture of the universe.”

The team tracked how the gravitational pull of massive dark matter structures can warp the CMB on its 14-billion-year journey to us, just as antique, lumpy windows bend and distort what we can see through them.

“We’ve made a new mass map using distortions of light left over from the Big Bang,” said Mathew Madhavacheril, a 2016-2018 Princeton postdoc who is the lead author of one of the papers and an assistant professor in physics and astronomy at the University of Pennsylvania. “Remarkably, it provides measurements that show that both the ‘lumpiness’ of the universe, and the rate at which it is growing after 14 billion years of evolution, are just what you’d expect from our standard model of cosmology based on Einstein’s theory of gravity.”

Sherwin added, “Our results also provide new insights into an ongoing debate some have called ‘The Crisis in Cosmology.’” This “crisis” stems from recent measurements that use a different background light, one emitted from stars in galaxies rather than the CMB. These have produced results that suggest the dark matter was not lumpy enough under the standard model of cosmology and led to concerns that the model may be broken. However, the ACT team’s latest results precisely assessed that the vast lumps seen in this image are the exact right size.

“While earlier studies pointed to cracks in the standard cosmological model, our findings provide new reassurance that our fundamental theory of the universe holds true,” said Frank Qu, lead author of one of the papers and a Cambridge graduate student as well as a former Princeton visiting researcher.

“The CMB is famous already for its unparalleled measurements of the primordial state of the universe, so these lensing maps, describing its subsequent evolution, are almost an embarrassment of riches,” said Staggs, whose team built the detectors that gathered this data over the past five years. “We now have a second, very primordial map of the universe. Instead of a ‘crisis,’ I think we have an extraordinary opportunity to use these different data sets together. Our map includes all of the dark matter, going back to the Big Bang, and the other maps are looking back about 9 billion years, giving us a layer that is much closer to us. We can compare the two to learn about the growth of structures in the universe. I think is going to turn out to be really interesting. That the two approaches are getting different measurements is fascinating.”

ACT, which operated for 15 years, was decommissioned in September 2022. Nevertheless, more papers presenting results from the final set of observations are expected to be submitted soon, and the Simons Observatory will conduct future observations at the same site, with a new telescope slated to begin operations in 2024. This new instrument will be capable of mapping the sky almost 10 times faster than ACT.

Of the co-authors on the ACT team’s series of papers, 56 are or have been Princeton researchers. More than 20 scientists who were junior researchers on ACT while at Princeton are now faculty or staff scientists themselves. Lyman Page, Princeton’s James S. McDonnell Distinguished University Professor in Physics, was the former principal investigator of ACT.

This research will be presented at “Future Science with CMB x LSS,” a conference running from April 10-14 at Yukawa Institute for Theoretical Physics, Kyoto University. The pre-print articles highlighted here will appear on the open-access arXiv.org. They have been submitted to the Astrophysical Journal. This work was supported by the U.S. National Science Foundation (AST-0408698, AST-0965625 and AST-1440226 for the ACT project, as well as awards PHY-0355328, PHY-0855887 and PHY-1214379), Princeton University, the University of Pennsylvania, and a Canada Foundation for Innovation award. Team members at the University of Cambridge were supported by the European Research Council.