Astronomers studying a rare Einstein cross stumbled in an impossible “fifth image” which should not exist – and it revealed something extraordinary.
A careful analysis has shown that the strange pattern of light could only be explained by the presence of a vast halo hidden of dark matter by folding the glow of the galaxy.
Discovery of a cosmic anomaly
When Rutgers’ theoretical astrophysicist, Charles Keeton, first saw an unusual image shared by his colleague, he was intrigued.
“Have you ever seen an Einstein cross with an image in the middle?” His colleague Andrew Baker asked, referring to a cosmic configuration rarely seen.
Keeton hadn’t done it. The implications were enormous.
“I said, well, it is not supposed to happen,” said Keeton, vice-prevôr for experiential learning at Rutgers-New Brunswick University. “You cannot get a fifth image in the center unless something unusual is happening with the mass that folds light.”
The mystery of Einstein Cross
An “Einstein cross” is a cosmic configuration rarely seen in which the light of a distant galaxy is folded by the gravity of the galaxies in front of it, creating four images. But the additional image of this Einstein cross stressed “something unusual”, which turned out to be a massive and hidden halo of dark matter. The existence of this invisible structure can only be deducted by careful IT modeling and analysis.
Halo of revealed dark matter
The discovery, made by an international team which includes Keeton, Baker and the student graduate of Rutgers, Lana Eid, is now published in THE Astrophysical Journal.
The dark matter constitutes the majority of matter in the universe, but we cannot see directly. “We know that this is because of how it affects the things we can see, as the way he bends the light of distant galaxies,” said Baker, a distinguished professor in the department of physics and astronomy at the school of arts and science and co-author of the study. “This discovery gives us a rare chance to study this invisible structure in detail.”
First clues of France
The first step towards this discovery was taken in France.
“We said to ourselves,” What is the Devil? ” “” Said Pierre Cox, French astronomer, research director at the French National Center for Scientific Research and Principal Author of the Study, who first spotted the data anomaly of the North Millimeters of the North (Noema) of radio stations in the French Alps.
“It looked like a cross, and there was this image in the center,” said Cox. “I knew I had never seen that before.”
Destroy the fifth image
The team studied a distant and dusty galaxy called Hers-3. Using the Noema and the large millimeter / submillimeter Atacama network (Alma) In Chile, they saw that the light of his own-3 is divided into five rather than four images. At first, they thought it could be a problem in the data. But the fifth image would not disappear.
“We tried to get rid of it,” said Cox. “We thought it was a problem with the instrument. But it was real.”
IT models expose the invisible
The computer modeling of the gravitational lens by Keeton and EID showed that the four visible leading galaxies causing gravitational flexion could not explain the details of the model with five images. It is only with the addition of a large invisible mass, in this case, a halo of dark matter, that the model could correspond to the observations.
“We have tried all the reasonable configurations using only visible galaxies, and none of them worked,” said Keeton, also a professor in the department of physics and astronomy and co-author of the study. “The only way to make the training of calculations and physics was to add a halo of dark matter. This is the power of modeling. This helps to reveal what you cannot see.”
A natural cosmic laboratory
The unusual configuration does not only look cool: scientists said it was scientifically precious. The lens effect amplifies the background galaxy, allowing astronomers to study its structure in more detail than usual. It also offers a rare chance to find out about the dark matter surrounding the leading galaxies.
“This system is like a natural laboratory,” said Cox. “We can study both the distant galaxy and the invisible matter that folds its light.”
EID, a student graduate of Rutgers continuing her doctorate and co-author of the study, said that her involvement in the research project was exciting from start to finish.
“I was delighted to join this project as a graduate student, especially since it involved a fascinating lens system which has become more intriguing as our models have evolved,” said Eid. “Collaboration on continents and time zones taught me the value of the expertise and diverse research styles to fully understand a new discovery.”
Predictions and future tests
The team even predicted that more characteristics, such as overflowing gas from the galaxy, could be visible in future observations. If these predictions are confirmed, it would be a powerful validation of their models. Otherwise, it would always teach them something new.
“This is a falsifiable prediction,” said Keeton. “If we look at and do not see it, we will have to return to the drawing board. This is how science works.”
Baker said the discovery had been criticized by international collaboration and American federal support for science. “Alma in Chile and the very large painting (VLA) in New Mexico are supported by the National Science Foundation, and the Foundation Hubble space telescope is supported by Nasa; All have played essential roles in this work, “he said.” We hope they will continue to allow such discoveries to the future. “”
Reference: “Hers-3: an exceptional cross from Einstein reveals Massive Halo of dark matter” by P. Cox, Km Butler, CR Keeton, L. Eid, E. Horso, TJLC Bakx, R. Neri, BM Jones, AJ Baker, AJ Baker, AJ Baker, A. Corsini, L. Marchetti, A. Omont, A. Beelen, D. Ismail, RJ Ivison, M. Krips, MD Lehnert, H. Messiah, D. Riechers, C. Vlahas, A. Weiss, P. Van Derf and C. September, The astrophysical newspaper.
Two: 10.3847 / 1538-4357 / ADF204
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