Tuesday, November 15, 2022

Shape Matters In Fuzzy Dark Matter Models

One way to conceptualize self-interacting gravitational fields in a quantum gravity context (in which the shape of the matter distribution is a major driver of non-Abelian gravitational effects) is to view gravitons as an ultra low mass-energy bosonic dark matter particle. 

So, it isn't too surprising that the share of the matter distribution matters in fuzzy dark matter models, which are among the stronger dark matter particle candidates.
A plausible dark matter candidate is an ultralight bosonic particle referred to as fuzzy dark matter. The equivalent mass-energy of the fuzzy dark matter boson is ∼10^−22eV and has a corresponding de Broglie wavelength of kiloparsec scale, thus exhibiting wave behaviour in scales comparable to a galactic core, which could not appear in conventional cold dark matter models. The presence of fuzzy dark matter in galactic clusters will impact the motion of their members through dynamical friction. 
In this work, we present simulations of the dynamical friction on satellites traversing an initially uniform fuzzy dark matter halo. We focus on the satellites whose shapes are beyond spherical symmetry described by ellipsoidal and logarithmic potentials. We find that the wakes created on the fuzzy dark matter halo due to the passage of such satellites are qualitatively different from those generated by spherically symmetric ones. Furthermore, we quantify the dynamical friction coefficient for such systems, finding that the same satellite may experience a drag differing by a factor of 5 depending on its ellipticity and the direction of motion. Finally, we find that the dynamical friction time-scale is close to Hubble time, assuming a satellite of 10^11M⊙ traversing at 10^3km/s a FDM halo whose mean density is ∼10^6M⊙kpc−3.
Andreas Vitsos, Konstantinos N. Gourgouliatos, "Dynamical Friction due to fuzzy dark matter on satellites described by axisymmetric logarthmic potentials" arXiv:2211.06752 (November 12, 2022).

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