How Dark Matter Influences the Rhythm of Cosmic Collisions ⚡ экспресс
The nature of dark matter is unknown, but two models stand out: cold (CDM) and self-interacting (SIDM) with a constant cross-section of 1 cm²/g, introduced to resolve discrepancies in central density profiles. Simulations show that SIDM delays mergers of massive black holes (MBHs) when the halo profile is flattened. Using simulated gravitational-wave observations of two galactic histories, the ability of LISA to probe dark matter was assessed: distinguishing CDM from SIDM (p ≤ 0.05) is possible with ~70 detected mergers with SNR >10. The sample is small, so conclusions are preliminary; models with variable cross-sections were not considered. The work illustrates the potential of LISA as a tool for investigating the microphysics of dark matter and justifies the need for larger-scale simulations.
Particles of dark matter can behave like molasses: in one model they don't interfere with each other; in another, they gently jostle, creating viscosity. This determines how quickly giant black holes at the centers of galaxies fall into each other and merge.
The LISA space observatory will catch gravitational waves from such mergers. If about 70 signals are registered, their frequency will reveal whether dark matter was viscous. This method is reminiscent of how, by the thud of falling apples, you can tell whether they landed on grass or in syrup. Remarkably, LISA is designed much like the human auditory system: three detectors, spaced millions of kilometers apart, act like our ears, picking up the tremors of spacetime.
🎯 Fritz Zwicky suspected dark matter's existence in 1933, and Vera Rubin proved it in the 1970s: galaxies rotate as if held by an invisible framework. Today it's clear—there's five times more dark matter than ordinary matter.