Cross-correlating CMB lensing and hydrogen intensity mapping
IFPU
15 – 19 April 2024
This research program explores the cross-correlation signal between the lensing of the Cosmological Microwave Background (CMB) and temperature maps of cosmic neutral Hydrogen obtained through Intensity Mapping (HI IM). HI IM provides a unique perspective on the Large Scale Structure (LSS) of the Universe, offering tomographic characterization of the matter field with unprecedented distance precision across extensive redshift ranges. However, the analysis is challenging due to intense astrophysical foregrounds and entanglement with calibration uncertainties and instrumental systematics. In contrast, CMB lensing serves as a measure of the integrated LSS, complementing HI IM information. The research aims to leverage their cross-correlation signal to address HI IM’s contaminant challenge and enhance the line-of-sight information of CMB lensing. This involves coherent simulation of the two observables, quantification of cross-correlation signals with and without realistic observational effects, and the development of statistical estimators to overcome disparate information content. Ultimately, the program seeks to characterize the cross-correlation signal and provide tools for forecasting and performing this measurement using existing CMB lensing and HI IM datasets.
Organisers:
- Matteo Calabrese (Osservatorio Astronomico della Valle d’Aosta)
- Isabella Paola Carucci (INAF, Trieste)
Participants
- Matteo Calabrese (Osservatorio Astronomico della Valle d’Aosta)
- Isabella Paola Carucci (INAF, Trieste)
- Giulio Fabbian (Cardiff University)
- Caroline Guandalin (The University of Edinburgh)