Speaker
Description
The kinetic Sunyaev--Zel'dovich (kSZ) effect is the dominant small-scale CMB blackbody anisotropy, and is sensitive to the electron density field as well as the large scale velocity field of the Universe. It has recently become possible to measure at high significance over a wide sky area with the Atacama Cosmology Telescope (ACT) data, and will be an even more significant signal in Simons Observatory (SO). In combination with a galaxy survey, we can use this signal to measure directly the velocity field of the high-redshift Universe for the first time through a process known as kSZ velocity reconstruction. One exciting application of this method is primordial non-Gaussianity constraints; the fNL constraints from kSZ velocity reconstruction with SO may be the tightest available.
I will present and discuss the first and most recent kSZ velocity measurements with the ACT DR6 data combined with the DESI Legacy galaxies, whereby we measure the velocity field of our Universe at high significance and use the measurement constrain primordial non-Gaussianity. I will present foreground removal techniques for this measurement, particularly relevant for future measurements with photometric surveys like LSST and Euclid. Finally, I will look to the near future and briefly present forecasts on the constraining power we will have on the non-Gaussianity parameter $f_{NL}$ with Simons Observatory