Observation by NASA/ Esa Hubble Space Telescope And European Southern Observatory Very large telescope In Chile (VLT) has found that some theory may be missing from how dark matter behaves. This missing component may explain how researchers have uncovered an unexpected discrepancy between dark matter concentrations in theoretical samples of large-scale galaxy clusters and theoretical computer simulations of how dark matter should be distributed across clusters. New findings indicate that some small-scale concentrations of dark matter produce lensing effects that are 10 times stronger than expected.
Dark matter is the invisible glue that holds stars, dust, and gas together in a galaxy. This mysterious substance forms the bulk of the mass of a galaxy and forms the foundation of the massive structure of our universe. Because Dark Matter does not emit, absorb, or reflect light, its presence is known only through its gravitational bridge over a visible matter in space. Astronomers and physicists are still trying to explain what it is.
The Galaxy Cluster, the largest and recently assembled structure in the Universe, has the largest reserves of dark matter. The clusters are made up of individual member galaxies that are largely held together by the gravity of dark matter.
“Galaxy clusters are ideal laboratories in which numerical simulations of the currently available universe can reproduce well what we can get from gravitational lensing,” Enef-Observatory of Astrophysics and Space Science of Bologna Said Massimo Meneggetti of Italy. Lead author of the study.
The video begins with an image of the giant galaxy cluster MACSJ 1206 from the NASA / ESA Hubble Space Telescope. Embedded within the cluster are distorted images of distant background galaxies, seen as arcs and smear features. These distortions are caused by dark matter in the cluster, whose gravity bends and magnifies the light farther away from the galaxies, which results in gravitational lensing. This phenomenon allows astronomers to study distant galaxies that would otherwise be too faint to see.
The video then shows an artist the impression of small-scale concentrations of dark matter (shown in this video in blue). Dark matter is an invisible glue that binds stars together inside a galaxy and creates heaps of this substance in the universe. These blue hollows demonstrate how the new results from the Hubble Space Telescope show that the dark matter of the galaxy cluster is distributed. This was accomplished by a team of astronomers to measure the amount of gravitational lensing.
Credit: NASA, ESA, G. Caminha (University of Groningen), m. Menegetti (Observatory and Astronomy of Astronomy), p. Natarajan (Yale University), The CLASH team, and M. Cornmeser (ESA / Hubble)
“We have tested the data a lot in this study, and we are sure that this mismatch is an indication that some physical components are missing from either simulation or our understanding of nature,” Menegetti said.
One of the senior theorists on the team, Priyamvada Natarajan of Yale University in Connecticut, USA, said, “There is a feature of the real universe that we are not capturing in our current theoretical model.” “This may indicate a difference in our current understanding of the nature of dark matter and its properties, as these exquisite figures have allowed us to examine the broadest distribution of dark matter on the smallest scale.”
This video shows the phenomenon of gravitational lensing of an artist.
Credit: ESA / Hubble and M. Cornmeasers
The distribution of dark matter in bunches is mapped by measuring the bending of light – the gravitational lensing effect – that they produce. The gravity of dark matter concentrated in bunches increases and heats the light from distant background objects. This effect produces distortions in the shape of background galaxies that appear in the images of clusters. Gravitational lensing can often produce multiple images of the same distant galaxy.
The higher the concentration of dark matter in a cluster, the more dramatically it has a light-bending effect. The presence of small-scale clumps of dark matter associated with individual cluster galaxies increases the level of deformations. In some sense, the galaxy cluster acts as a large-scale lens with several small lenses embedded within it.
Hubble’s crisp images were taken for survey by Telescope’s Wide Field Camera 3 and Advanced Camera. Coupled with spectra from the European Southern Observatory’s Very Large Telescope (VLT), the team produced an accurate, high-fidelity, dark-matter map. By measuring lensing distortions, astronomers can detect the volume and distribution of dark matter. The three major galaxy clusters, MACS J1206.2-0847, MACS J0416.1-2403, and Abel S1063, were part of two Hubble surveys: the Cluster Lining and Superbova survey with Frontier Fields and Hubble (CLASH) programs.
To the team’s surprise, in addition to the dramatic arcs and elongated features of distant galaxies created by the gravitational lensing of each cluster, the Hubble images also revealed an unexpected number of unexpected small-sized arcs and distorted images near the core of each cluster, Where galaxies reside on the largest scale. Researchers believe that nested lenses are formed by gravity of dense concentrations of matter inside individual cluster galaxies. Subsequent spectroscopic observations measured the velocity of stars, orbiting inside multiple galaxies to pin their mass.
“The data from Hubble and VLT provided excellent synergy,” shared Pierro Rosati, a team member of the Università deli Studi di Ferrara in Italy, who led the spectroscopic campaign. “We were able to connect galaxies with each cluster and estimate their distances.”
“The motion of the stars gave us an estimate of the mass of each individual galaxy, including the amount of dark matter,” said Pietro Bergamini, a member of the Astro-Observatory and Astronomy team in Bologna, Italy.
By combining Hubble imaging and VLT spectroscopy, astronomers were able to identify dozens of multiply, lensed, background galaxies. This allowed them to assemble a well-calibrated, high-resolution map of the mass distribution of dark matter in each cluster.
The team compared Dark Matter maps with samples of equally spaced simulated galaxy clusters with similar mass. Clusters in the computer model did not show any level of similar level of dark-matter concentration at the smallest levels – scales associated with individual cluster galaxies.
“The results of these analyzes further demonstrate how observations and numerical simulations go hand in hand”, said team member Elena Rasia of the IAAF-Astronomical Observatory Trieste, Italy.
“With advanced cosmological simulations, we can match the quality of the observations analyzed in our paper, like never before,” said Stefano Borgany of the Université deli Studi de Trieste, Italy.
Astronomers, of this team, look forward to continuing to investigate the dark matter and its mysteries so that its nature may eventually be undermined.
Read Hubble’s Shocking Dark Matter Discovery: Observations suggest a missing ingredient in the cosmic recipe for more on this discovery.
References: “Massimo Menegetti, Guido Davoli, Pietro Bergamini, Piero Rosati, Priyamvanda Natarajan, Carlo Giocoli, Gabriel B. Caminha, R. Benton Metcalfe, Elena Rasia, Stefano Borgano,” An additional number of small-scale gravitational lenses of galaxy groups. Is seen in , Francesco Calura, Claudio Grillo, Amata Mercurio and Eros Vanzella, 11 September 2020, Science.
DOI: 10.1126 / science .ax 5164
The Hubble Space Telescope is a project of international collaboration between ESA and NASA.
In this study M. in the International Team of Astronomers. Menegatti, G. Davoli, p. Bergamini, p. Rosati, p. Natarajan, c. Giacoli, GB Caminha, RB Metcalf, E. Rasiya, s. Borgani, f. Calura, c. Grillo, a. Mercurio, and E. Wangela