Public Seminar of RPg Student:- Perturbations by Wave Dark Matter on Gravitationally Lensed Galaxy Velocity
The ΛCDM paradigm has been successful in reproducing the large-scale structure of the universe and the matter power spectrum. However, the main challenges of CDM lie in the small-scale, most notably the cusp-core problem and the missing satellite problem. As opposed to resorting to baryonic physics such as supernova feedback and tidal disruption, wave or fuzzy dark matter(ψDM) might provide viable explanations to the small-scale anomalies. ψDM consists of ultra-light bosons of ∼10−22eV in a Bose-Einstein condensate, such mass entails the bosons to possess de Broglie/Jeans length in galactic scale. ψDM simulations show DM halos are permeated by density fluctuations on the de Broglie scale, manifesting as a granular pattern because of the quantum interference of the bosons. This granularity is of particular interest to strong gravitational lensing because of its potential to perturb the lensed image’s position and magnification. In a galaxy-galaxy lensing scenario, the observed velocity field of the background galaxy could be significantly perturbed by the granulation. The speaker and his team work aims to simulate the observed velocity fields of real galaxy samples and quantify the effects of different parameters of the foreground galaxy as well as the source-lens alignment.
地點：香港大學 莊月明物理樓522室 (網上講授)經ZoomID: 933-6317-6017
講者：Chun Hei YEUNG(香港大學)