Tackling challenges in cosmological probes from CMB, large-scale-structures to HI intensity maps
29. April 2022 - 11:30
Tianyue Chen (EPFL)
Abstract: We are currently in the era of precision cosmology where CMB measurements have constrained the standard cosmology model with sub-percent accuracy. In the past decade, late-time observations from large-scale-structure (LSS) surveys provide additional constraints on the Dark Energy. Meanwhile, the upcoming 21cm intensity mapping experiments aim to probe the Universe in a wider redshift range in the radio window. However, subtracting scientific signals for cosmology analysis from observed data has always been a common challenge for all cosmological probes. Such challenges include separating bright astrophysical foregrounds from the CMB or 21cm signal, and mitigating instrumental systematics. In this talk, I will firstly present my recent work on understanding the thermal SZ effect as one type of the foreground contaminations in the CMB temperature and lensing maps through the cross-correlation with LSS maps. In the other half of the talk, I will give the update on the latest 21cm detection using the CHIME telescope. I will present a time-redundant calibration algorithm we developed based on the observed CHIME data and a novel component separation technique to simultaneously subtract both foregrounds and systematics from 21cm signals.