PIRSA:25100109 Scientific Series Cosmology

DOI10.48660/25100109

Series: Cosmology and Gravitation

Anil Kumar, N. (2025). Cosmology from Cross-Correlations: The Kinetic Sunyaev–Zel’dovich Effect & Galaxy Surveys. Perimeter Institute. https://pirsa.org/25100109

Anil Kumar, Neha. Cosmology from Cross-Correlations: The Kinetic Sunyaev–Zel’dovich Effect & Galaxy Surveys. Perimeter Institute, Oct. 16, 2025, https://pirsa.org/25100109 

@misc{ pirsa_PIRSA:25100109,
  doi = {10.48660/25100109},
  url = {https://pirsa.org/25100109},
  author = {Anil Kumar, Neha},
  keywords = {Cosmology},
  language = {en},
  title = {Cosmology from Cross-Correlations: The Kinetic Sunyaev{\textendash}Zel{\textquoteright}dovich Effect \& Galaxy Surveys},
  publisher = {Perimeter Institute},
  year = {2025},
  month = {oct},
  note = {PIRSA:25100109 see, \url{https://pirsa.org}}
}

Abstract

With increasingly precise measurements of the small-scale cosmic microwave background (CMB), the kinetic Sunyaev–Zel’dovich (kSZ) effect has emerged as a powerful probe of cosmology and astrophysics through cross-correlations with galaxy surveys. In this talk, I will review established applications, focusing on large-scale velocity reconstruction and its ability to test signatures of the early universe, such as primordial non-Gaussianity and compensated isocurvature perturbations. I will then introduce a new way to combine these data sets, which provides unique constraints on the distribution of ‘missing baryons’ at low redshifts, thereby opening a new window on baryonic feedback and cosmological inferences from the small-scale distribution of matter. Finally, I will explore the sensitivity of this statistic to the epoch of helium reionization, and compare its prospects to other proposed probes such as optical-depth fluctuations in the observed CMB.

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