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[ZOOM강연]25.08.01-Dark Matter under the Gravitational Lens
저자 : 한국천문학회	등록일시 : 2025-07-29 11:42:42
첨부파일 :
Dear all, I am pleased to inform you that there will be an online UST talk on radio interferometry as linked in https://gmc.ust.ac.kr/prog/gmcLctr/global/sub01_08/list.do You are welcome to join the talk to be held on August 1 (Friday) at 3:00 pm as follows: 1. Speaker: Prof. Jeremy Lim    (University of Hong Kong, Hong Kong ) 2. Topic:    Dark Matter under the Gravitational Lens 3. Date/time:     2025-08-01 15:00 ~ 16:30    (KST) 4. Zoom info: Zoom Link:    https://zoom.us/j/97264803376?pwd=y6U9FRsTDlbS1g0qkDJgxdayhAsjqC.1 IID : 972 6480 3376 PW : 1234 5. Abstract  Discovered via its gravity in galaxy clusters nearly a century ago and subsequently confirmed from studies of individual galaxies as well as temperature anisotropies in the Cosmic Microwave Background, Dark Matter (DM) is now known to make up ~85% of all matter in the Universe.   Yet, the particles or objects that make up Dark Matter remain a complete mystery.  There is no candidate for DM among par ticles in the Standard Model of particle physics, making DM the clearest sign that the Standard Model of particle physics is incomplete.  A determination of the nature of DM – e.g., the DM particle mass – will rule out entire classes of hypothetical extensions to the Standard Model, thus pointing the correct path towards New Physics.  As no DM particle has yet been detected in laboratory experiments, astronomical observations remain the only tool for deducing the nature of DM.   In this presentation, I describe how gravitational lensing can differentiate between the two top contenders for DM: ultra-massive (WIMPs) versus ultra-light (Axion or Axion-like) particles, both hypothesized in different theoretical extensions to the Standard Model.  Specifically, I show how DM in the form of ultra-light particles (mass ~10^-22 eV) can resolve a two-decade old problem in gravitational lensing, whereby galaxy DM models based on ultra-massive particles leave discrepancies between the predicted and observed properties of multiply-lensed images.  Separately, I briefly mention our recent work showing how the spatial distribution of lensing transients in galaxy clusters require DM to be in the form of ultra-light rather than ultra-massive particles.   The increasing success of ultra-light DM particles in explaining not just these but other astronomical observations tilt the scale to new physics involving ultra-light DM particles. Best regards, Sang-Sung Lee