• Physics 15, s148
A proposed research of dwarf galaxies might give perception into whether or not darkish matter particles work together with one another.
ESA, Hubble, and NASA
Dwarf galaxies are a thorn within the aspect of cosmologists, as their central areas don’t match predictions from the chilly darkish matter (CDM) mannequin that’s thought of normal. Theorists have proposed explanations involving both the consequences of supernovae or a modification of the CDM mannequin, however each options have lacked empirical assist. A brand new research suggests a technique to discriminate between them by measuring the distribution of stars within the facilities of dwarf galaxies [1].
The CDM mannequin predicts that each one galaxies ought to have a “cusp”—a pointy density peak on the galactic middle. Nonetheless, some dwarf galaxies have a uniform-density “core” of their central areas. Astrophysicists normally clarify these cores with a supernova-feedback mannequin, through which robust winds from stellar explosions push matter out of the middle. Nonetheless, one other chance is that dark-matter particles scatter off one another, smoothing out the dense areas (see Synopsis: Self-Interacting Darkish Matter Scores Once more). Such interactions would have penalties for efforts to detect darkish matter.
To differentiate between fashions, Jan Burger from the Max Planck Institute for Astrophysics in Germany and colleagues explored potential astronomical signatures of supernova suggestions. They ran detailed pc simulations of a dwarf galaxy experiencing sudden bursts of star formation—a mandatory ingredient to provide sufficiently robust winds. In plots of velocity vs distance, they discovered that stars of comparable age and composition clustered in shells. “Discovering such signatures would get rid of the necessity for extensions of the CDM mannequin,” Burger says. Present telescopes would have issue recognizing the shells, however the workforce expects that the Nancy Grace Roman Area Telescope (at the moment scheduled for a mid-2020s launch) might doubtlessly take a look at whether or not any close by dwarves host star-packed shells.
–Michael Schirber
Michael Schirber is a Corresponding Editor for Physics Journal based mostly in Lyon, France.
References
- J. D. Burger et al., “Kinematic signatures of impulsive supernova suggestions in dwarf galaxies,” Phys. Rev. Lett. 129, 191103 (2022).
