Astro Seminar Series - VIA Zoom

Wednesday, October 6, 2021 11:30 am - 11:30 am EDT (GMT -04:00)

Chen Heinrich
Chen Heinrich is a postdoc in cosmology at California Institute of Technology. She obtained for Ph.D. in 2017 from University of Chicago, where she specialized in the cosmic microwave background (CMB) under the supervision of Prof. Wayne Hu. She quantified the effects of gravitational lensing on measuring compensated isocurvature perturbations with the CMB, and conducted studies of reionization and inflation with Planck. Chen now focuses on developing the cosmological analysis pipeline in SPHEREx for measuring primordial non-Gaussianities; she has also been part of the Nancy Grace Roman Space Telescope since her first postdoc at the Jet Propulsion Laboratory in 2017, preparing for its investigations of dark energy and modified gravity.

Talk Title and Abstract:

RELIKE - Reionization Effective Likelihood from Planck Legacy Data

The Planck legacy data is currently the best full-sky measurement on the cosmic microwave background. To fully take advantage of its superb measurement on large-scale CMB polarization for constraining reionization, we build and release RELIKE — a fast and accurate effective likelihood code, using the technique of reionization principal components. With this code release (https://github.com/chenheinrich/RELIKE), one can now quickly test the likelihood of any reionization model between redshifts 6 < z < 30 in just a few lines of python code. Instead of using the optical depth constraint obtained from an instantaneous reionization model, RELIKE now enables a fast and consistent way of combining Planck constraints with other reionization data sets for which the ionization evolution is important (e.g. line-intensity mapping, luminosity function, star formation history, quasar spectra). In the second part of the talk, I will also give a brief update on ongoing work in the SPHEREx mission. SPHEREx aims to measure primordial non-Gaussianities with unprecedented precision (sigma(fNL) ~ 1) to determine a key property of inflation. To achieve this precision, accurate modeling of the power spectrum and bispectrum are needed. I will describe ongoing work (and challenges) that we face in this area as we prepare for the first time full-sky measurement of large-scale structure with SPHEREx.

Would you like to join this Zoom seminar?  Please email WCA.