PIRSA:25110113

Constraining primordial non gaussianity from DESI DR1 quasars sample and Planck PR4 CMB lensing

Chiarenza, S. (2025). Constraining primordial non gaussianity from DESI DR1 quasars sample and Planck PR4 CMB lensing. Perimeter Institute. https://pirsa.org/25110113

Chiarenza, Sofia. Constraining primordial non gaussianity from DESI DR1 quasars sample and Planck PR4 CMB lensing. Perimeter Institute, Nov. 17, 2025, https://pirsa.org/25110113 

          @misc{ pirsa_PIRSA:25110113,
            doi = {10.48660/25110113},
            url = {https://pirsa.org/25110113},
            author = {Chiarenza, Sofia},
            keywords = {Other},
            language = {en},
            title = {Constraining primordial non gaussianity from DESI DR1 quasars sample and Planck PR4 CMB lensing},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {nov},
            note = {PIRSA:25110113 see, \url{https://pirsa.org}}
          }

Sofia Chiarenza

Talk numberPIRSA:25110113
DOI10.48660/25110113
Collection
Talk Type Scientific Series
Subject

Abstract

We present the first measurement of primordial non-Gaussianity from the cross-correlation between 1.2 million spectroscopically confirmed quasars from the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI) and the Planck PR4 CMB lensing maps. The analysis is performed in three tomographic redshift bins covering 0.8 < z < 3.5, covering a sky fraction of ~20%. We adopt a catalog-based pseudo-C_l estimator and apply linear imaging weights validated on noiseless mocks. Compared to previous analyses using photometric quasar samples, our results benefit from the high purity of the DESI spectroscopic sample, the reduced noise of PR4 lensing, and the absence of excess large-scale power in the spectroscopic quasar auto-correlation. Fitting simultaneously for the non-Gaussianity parameter f_NL and the linear bias amplitude in each redshift bin, we obtain f_NL} = 2^{+28}_{-34} for a response parameter p=1.6, and f_NL = 6^{+20}_{-24} for p=1.0. These results improve the constraints on f_NL by $\sim 35\%$ compared to the previous analysis based on the Legacy Imaging Survey DR9. Moreover, despite relying solely on cross-correlations over a smaller sky area, our constraints are competitive with the best current limits from photometric quasar catalogs, coming from an analysis performed with the \emph{Quaia} sample. Our results demonstrate the statistical power of DESI quasars for probing inflationary physics, and highlight the promise of future DESI data releases.