Zoom-in, a computer-generated simulation of the distribution of dark matter in the universe, also known as the cosmic web. The tiny, spherical blobs of dark matter that appear scattered throughout the image are known by scientists as dark matter haloes, gravitational structures that form galaxies. Image by J. Wang; S. Bose / CFA.
Originally published by the Harvard-Smithsonian Center for Astrophysics on September 2, 2020, headquartered in Cambridge, Massachusetts.
Using the power of supercomputers, an international team of researchers has zoomed in on the tiny huts of dark matter in the virtual universe. Published September 2, 2020, in the peer-reviewed journal Nature, The study showed the lure of dark matter as active regions of the sky, not only with galaxies, but also collisions of radiation-emission that could make it possible to detect this halo in the real sky.
Dark matter – which makes up about 83% of matter in the universe – is a key player in global evolution, including the formation of galaxies, which cool the gas and condense at the center of specific lumps of dark matter. Over time, a halo was formed due to their own tremendous gravity pulling the clusters of some dark matter away from the expansion of the universe. The largest dark matter halos have huge galaxy clusters – a collection of hundreds of galaxies – and while their properties can be inferred by studying the galaxies within them, the smallest dark matter, which usually lacks a single star, remains a mystery. .
Sonak Bose is one of the leading authors on new research at CFA. He said:
One of the things we have learned from our simulations is that gravity leads to ‘clamping’ of dark matter particles in overgrown areas of the universe, which settles in what is known as dark matter. These can be thought of as large gravity wells filled with dark matter particles.
We think that every galaxy in the universe is surrounded by a wide distribution of dark matter, which is more than the luminous content of a galaxy within a factor of 10 to 100, depending on the type of galaxy. Because this dark matter surrounds the entire galaxy in all directions, we call it the ‘halo’.
Sonak Bose is a postdock at the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics (CFA). It uses the largest cosmological structures in our universe – called the cosmic web – and huge numerical simulations to study the evolution of galaxies. Image by CFA.
In the virtual universe simulated by these scientists, researchers were able to zoom in with the precision required to identify fleas on the surface of the full moon – from seven zeros to 10, or up to a power of 10 – and the most anticipated little known virtual dark matter haloes. Bose explained:
Simulations are helpful because they help us to quantify not only the overall distribution of dark matter in the universe, but also the detailed internal structure of these dark matter. The abundance of the full range of dark matter haloes formed in the Cold Dark Matter model and the establishment of the internal structure is interesting as this enables us to calculate how easy it can be to find a dark object in real calculations.
While studying the formation of haloes by their imitation, the researchers found a surprising way: haloes of all dark matter, whether large or small, have very similar internal structures that have a ga ense in the center and spread further and further. Astronomer Ji Wange at the National Astronomical Observatories (NAOC) in Beijing and lead author on the research said:
Some previous studies suggest that the density profiles for super-mini haloes will be quite different from their larger counterparts. Our simulations show that they look alike in a huge set of dark colored haloes and that’s amazing.
Bose added that even in the smallest halo that is not around galaxies:
Our simulations enable us to visualize the so-called ‘cosmic web’. Where the filaments of dark matter intersect, one sees tiny spherical blobs of dark matter, which are haloes themselves, and are so universal in their composition that I can show you a picture of a galaxy cluster with a mass of a billion billion times. The Sun, and the Earth-mass halo, which is a million times smaller than the Sun, and you can’t tell what it is.
Ji Wang, an astronomer at the National Astronomical Observatories in Beijing, is the lead author on the new research. Image by NOAC.
Although images of dark matter haloes from this study are the result of simulations, these simulations are reported by actual observation data. For astronomers, this means that the study can be mimicked against the actual night sky by looking at real technology. Bose said:
The initial conditions that went into our simulation are based on actual observational data from the Planck Satellite’s cosmic microwave background radiation measurements, which tell us what the universe is made of and how much darker matter to place.
During the study, researchers tested a feature of the halo of dark matter that could make it easier to find them in the real night sky: subtle collisions. Current theory suggests that dark matter particles colliding near the center of the halo can explode in a violent explosion of high-radiation gamma radiation and possibly detect a halo of dark matter through ally ga dark-rays and other telescopes. Bose said:
Exactly how the radiation will be detected depends on the specific properties of the dark matter particles. In the case of large particles (WIMP) weakly interacting, which is one of the leading candidates in the standard cold dark matter picture. [currently the most popular theory among scientists to explain the nature of dark matter], Gamma radiation is usually produced in GV [gigaelectronvolt] Series. Fermi data claims to have more galactic centers than gave-scale gamma radiation, which may be due to dark matter or perhaps due to pulsars.
Wang added:
Ground based telescopes such as the Very Energetic Radiation Imaging Telescope Array System (VERITAS) can also be used for this purpose. And, telescopes directed at galaxies other than our own can also help, as this radiation should be generated in the pools of all black matter.
With knowledge of our simulations, we can evaluate many different tools for detecting halo – gamma-ray, gravitational lensing, dynamics. These methods are all promising in the operation to shed light on the nature of dark matter particles.
The results of the study provide a way for both current and future researchers to better understand what is out there, whether we can see it or not. Bose said:
Understanding the nature of dark matter is one of the sacred grails of cosmology. While we know that it dominates the gravity of the universe, we know very little about its basic properties: how heavy individual particles are, what kind of interactions they have, if any, they have with ordinary things, Etc. Through computer simulation, we come to know about its fundamental role in the formation of the structure in our universe. In particular, we have come to realize that without dark matter, our universe would not be what it used to be. There will be no galaxies, no stars, no planets and therefore no life.
This is because the dark matter acts as the formation of the invisible skeleton that holds the visible universe around us.
Zoom in, a computer-generated simulation of the distribution of dark matter in the universe, also known as the cosmic web. Inset: From the highest level of uniqueness small yellow flowers or earth mass dark objects are illuminated as they appear in the universe today. When they exist in the corresponding area of the background, they often appear only after zooming. This is the first time these objects have ever been created in a numerical simulation. J. Image by Wang / S. Bose / CFA.
Bottom line: Researchers in the US and China have used supercomputers to detect dark matter haloes in the virtual universe. This work displays the lure of dark objects as active regions of the sky, not only with constellations, but also with radiation-emitting collisions that can make it possible to detect a halo of dark matter in the real sky.
Source: The universal structure of dark matter is in the mass range of magnitude of 20 orders of magnitude.
By CFA
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