Dark matter theory solves 2 astrophysical puzzles at once

Studying dark matter, a hypothetical form that represents about 85% of matter in the universe, is literally the same as working in the dark. After all, unlike ordinary matter, The dark one got this name because it does not absorb, reflect or emit light. This means it cannot be directly observed by optical means, making its detection even more difficult.

This theory, in constant search for something unseen, was published in 2003. This theory, called “self-interacting dark matter” (SIDM), proposes that dark matter particles interact with each other. through a dark force, also invisible, that collide powerfully with each other near the center of the galaxies.

Recently, a team of astronomers led by scientists from the University of California, Riverside, USA, showed in a study published in The Astrophysical Journal Letters that SIDM can simultaneously explain two astrophysical puzzles at opposite ends.

Simulating the workings of self-interactive dark matter theory

To show that SIDM can solve both astrophysical puzzles, the team performed the following: First high-resolution computer simulations to evaluate how this proposition would work in the Universe. In this sense, they focused on strong gravitational lensing halos and ultra-diffuse galaxies.

According to lead researcher Hai-Bo Yu from UC Riverside in the US, “the first [enigma] It is a halo of high-density dark matter in a massive elliptical galaxy.” It may have been detected through strong gravitational lensing, which occurs when light from distant galaxies traveling through space is “bent” around supermassive objects.

The second problem is Dark matter halos in ultra-diffuse galaxies (in very low light). They have low densities and are difficult to explain by cold dark matter theory, which conceptualizes this form as particles moving slowly relative to the speed of light.

A new SIDM model explaining dark matter

According to Ethan Nadler of the University of Southern California, first author of the paper, in both simulated cases “these self-interactions lead to heat transfer in the halo, which varies the halo density in the central regions of the galaxies.”

This means that the central density of some halos is higher and others lower, compared to light dark matter.

Therefore, the current study presents a new speed-dependent SIDM model. Using the N-body computational model, the researchers simulated strong dark matter self-interactions at galaxy group scales. Halos and subhalos have been detected, which can explain both the strong gravitational lensing effect and the effect of extremely diffuse galaxies.

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