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Past Events
Public Seminar of MPhil Candidate:
Geometric Redshifts for Distant Faint Galaxies
| Speaker: | Mr. Ming Yan CHAN |
| Affiliation: | The University of Hong Kong |
| Date: | January 30, 2018 (Tuesday) |
| Time: | 2:30 p.m. |
| Venue: | Rm 518, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract
The formation and evolution of galaxies is one of the major frontiers in contemporary astrophysics. Searches for and studies of distant and therefore young galaxies are necessary for testing and developing theoretical models for their assembly in the early universe. Through gravitational lensing by galaxy clusters, astronomers have been able to probe a few magnitudes deeper than blind surveys. To infer the intrinsic properties of lensed images, the most challenging aspects are to accurately derive the redshifts and magnifications of the lensed images which requires accurate lens models. My thesis addresses these problems by using redshifts derived purely geometrically. In my first project, I derived the geometric redshift of the triply-lensed galaxy MACS0647-JD, which is claimed to be one of the known earliest and most distant galaxies. In my second project, I explore the possibility of using geometric redshifts to refine the lens model for a galaxy cluster. The two projects provide a pioneering study of geometric redshift techniques that I anticipate will be used extensively in the future, towards the launch of JWST when photometric redshifts will be even more unreliable in the infrared regime.
Anyone interested is welcome to attend.