Cosmology with 3D maps of the Universe

Events Calendar

 Time:  Thursday, December 29, 2022, 09:00am
 Title:  Cosmology with 3D maps of the Universe
 Speaker:  Dr. Cheng Zhao (EPFL)
 Location:  S727 & Online via Zoom


The spatial clustering of large-scale structures (LSS) offers insights into the expansion history of the Universe and the growth of structures, and are foreseen to tackle the mysteries of the dark energy and dark matter. Precise cosmological constraints with clustering measurements require the 3-D positions (2-D angular position and redshift) of numerous tracers, and a large sample volume. To this end, the SDSS project collected ~3 million spectra in the past 15 years, and provided an uninterrupted view of the cosmos over the last 11 billion years. The ongoing Dark Energy Spectroscopic Instrument (DESI) project aims at increasing the number of redshifts by another order of magnitude.

In this talk, the speaker will review the state-of-art techniques for converting the redshift measurements into cosmological constraints, including theoretical modelling, simulations, and data analysis methods. In addition, the speaker will proposal future developments towards increasing both the precision and reliability, and discuss possibilities of joint cosmological constraints with the upcoming large-scale spectroscopic survey, wide-field imaging survey, and Hydrogen mapping data.


Cheng Zhao (赵成) received his BSc (2012) and PhD in astrophysics (2018) from Tsinghua University. Then he spent 4 years in Switzerland as a postdoctoral fellow at EPFL.

His research interests focus on revealing the nature of dark matter and dark energy through a multi-probe and multi-tracer manner. His research experience include data processing, simulation, theoretical modelling, and cosmological analyses with the large-scale distributions of galaxies, quasars, and voids.  

Since 2014, he has been participating in or leading key projects of the state-of-art large-scale spectroscopic surveys, including the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), SDSS-IV Extended BOSS (eBOSS), and the ongoing Dark Energy Spectroscopic Instrument (DESI).

Host: Hui Li