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Simply excellent: Dark Matter

Andreea Font does not work for, consult, own shares in or receive funding from any company or https://amazonia.fiocruz.br/scdp/blog/purdue-owl-research-paper/poverty-of-the-united-states.php that would benefit from this article, and has disclosed no relevant affiliations beyond their Dark Matter appointment. The search for dark matter — an unknown and invisible substance thought to make up the Matteg majority of matter in the universe — is at a crossroads. Although it was proposed nearly 70 years ago and has been searched for intensely - with large particle colliders, detectors deep underground and even instruments in space — it is still nowhere to be found. The idea is to extract information from astrophysical objects that may have Dark Matter chunks of it as they were passing by.

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Physicists believe that Dark Matter matter has a propensity to structure itself into a hierarchy of haloes and subhaloes, via gravity. The masses of these clumps fall on a spectrum, with lower mass ones expected to be more numerous. Is there a limit to how light they Mather be? It depends on the nature of the dark matter particles. Dark matter cannot be seen directly. We know it exists because we can see the gravitational effects it has on surrounding matter.

Warm versus cold

There are different theories about what dark matter may actually be. The standard model suggests it is cold, meaning it moves very slowly and only interacts Mather other matter through the force of gravity. Another theory, however, suggests it is warm, meaning it moves at higher speeds. One such particle candidate is the sterile neutrino. If dark matter is cold, a Milky Way-type galaxy could harbour one or two subhaloes weighing as much as 10 10 Suns, and most likely hundreds with masses of around 10 8 Suns.

If dark matter Dark Matter warm, haloes lighter than around 10 8 Suns cannot form easily. So tallying light mass dark haloes can tell us something about the nature of dark matter. We believe that the existence of lower mass haloes can be revealed by carefully planned observations. Astronomers have already got pretty Dark Matter at this game click to see more hide and seek with Dark Matter matter haloes and have devised observations to pick up the damage they leave behind.

To date, observations have targeted mostly the changes in the distribution of stars in the Milky Way. For example, the Large Magellanic Cloud, a smaller galaxy orbiting ours, seems to have a dark matter halo which is massive enough to trigger an enormous wake — driving the Dark Matter from across vast regions to move in unison. A few of the smaller dark matter haloes thought to be whizzing inside the Milky Way may occasionally pierce through large stellar features, such as globular clusters spherical Dagk of starsleaving tell-tale gaps in them. Darj matter haloes can also affect how light bends around astrophysical objects in a process called gravitational lensing.

Another way to probe the effect of haloes is by looking at the galactic gas it affects. Galaxies have plenty of hot gas with a temperature of around 10 6 degrees Kelvin which extends out to their edge, providing a wide net for catching these dark matter haloes.

Using a combination of analytical calculations and computer simulations, we have shown that dark haloes heavier than 10 8 solar masses can compress the hot gas through which they are moving. These will create local spikes in the density of the gas, Darm can be picked up by X-ray telescopes. These are predicted to be minute, of the order of a few per cent, but they will be within the reach of the upcoming Lynx and Athena telescopes. Our models also predict that the spikes in the density of the cooler galactic gas with temperature of around 10 5 K will be even more significant.

This means that the cooler Dark Matter can record the passage of Matrer matter haloes even more sensitively than the hot gas. Another promising way of observing the dark-matter-induced fluctuations in the gas is via the photons light particles from the cosmic microwave background — the light left over from here Big Bang. This light scatters off the highly energetic electrons in the hot gas Dark Matter a way that we can detect, providing a complementary approach to the other studies. Over the next few years, this new method can be used to test models of dark matter. Regardless of whether dark matter haloes below 10 8 solar masses are found in the numbers predicted or Dark Matter, we will learn something useful.]