SZ Effect and Cosmology

Our research is centered on the study of the Sunyaev-Zeldovich (SZ) effect from galaxy clusters, which is a tiny modification of the intensity of the cosmic microwave background (CMB) radiation, caused by inverse Compton scattering off the energetic electrons in the intracluster plasma. The SZ effect is a powerful tool in the study of galaxy cluster astrophysics and cosmology, providing information on topics as divers as the accelerated expansion of the universe and cosmic ray composition within AGN jets.

For over one decade we have been involved in the APEX-SZ cluster survey, using one of the world's first multi-pixel TES bolometer cameras, mounted on the APEX telescope in Chile. The data products from APEX-SZ are still being analyzed, while our research has moved onto multi-wavelength follow-up of galaxy clusters,  particularly in X-rays and at radio wavelengths. Another focus of our SZ research had been the analysis of all-sky data from the Planck satellite, which we are using to gain expertise on SZ spectral measurements and prepare for future multi-wavelength CMB/SZ surveys.

At the moment, much of our scientific activities are centered on the CCAT-prime telescope, which will undertake one of the most sensitive and most wide-spectrum surveys of galaxy clusters. This survey will start collecting data as early as 2021, and our team in Bonn is heavily involved in all the relevant aspects of scientific and instrumental planning. The list of Bachelor's/Master's and PhD thesis topics on the right will give some idea on the breadth of our research.

To get a more general understanding of the many different aspects of the SZ effect and their impact on cosmological research, please have a look at the two recent papers listed below. One was prepared for the Astro 2020 Decadal Survey in the US, the other was prepared for the ESA Voyage 2050 call for their long-term scientific planning. 

  1. "SZ spectroscopy" in the coming decade: Galaxy cluster cosmology and astrophysics in the submillimeter (arXiv:1903.04944)
  2. A Space Mission to Map the Entire Observable Universe using the CMB as a Backlight (arXiv:1909.01592)


For any question regarding SZ science, its future prospects, or the research opportunities in this group, please contact Dr. Kaustuv Basu or write him an Email.