| Speaker: | Liang Dai (IAS, Princeton) |
|---|---|
| Title: | New applications of gravitational lensing to probe dark matter substructure |
| Date (JST): | Thu, Jun 28, 2018, 15:30 - 16:30 |
| Place: | Seminar Room B |
| Related File: | 2112.pdf |
| Abstract: | Recent observations have uncovered new types of gravitational lensing phenomena that can be utilized to address fundamental physics questions. In galaxy cluster strong lensing systems, background galaxies straddle the lensing caustic and individual stars near the caustic have been detected by the HST thanks to the extreme magnification. I study how we can use caustic-crossing stars to probe small subhalos or other small-scale granularity in the cluster's halo beyond the reach of existing methods, thus constraining the microscopic nature of the dark matter. For another application, I discuss how small dark matter subhalos can leave lensing-induced wave diffraction imprints in the gravitational wave signals of binary mergers. To search for this effect, I present an agnostic and efficient algorithm based on random processes, which can enable the detection of both lensing-induced diffraction and other general waveform distortions in the gravitational wave data. |
