Measuring local primordial non-Gaussianity from the clustering of DESI DR1 LRGs and QSOs

Abstract

We report the first measurement of primordial non-Gaussianity (PNG), parameterized by $f_{\mathrm{NL}}$, in the configuration space two-point correlation function (2pcf). We employ simulation based modeling and a novel approach for the mitigation of imaging systematics. We apply this method to samples of luminous red galaxies (LRG) and quasars (QSO) observed by the Dark Energy Spectroscopic Instrument (DESI) during the first year of its observations (DR1). The observed 68\% CL interval on $f_{\mathrm{NL}}$ is $-3_{-21}^{+22}$ using LRGs, and $0_{-16}^{+17}$ using QSOs. The joint measurement yields $f_{\mathrm{NL}}=-3_{-12}^{+12}$ at $[68\%]$ CL. Our pipeline imposes a Gaussian prior on the value of $p$ (which defines the PNG bias via the Universality relation), with $p_{\mathrm{LRG}}=1.0\pm 0.1$ and $p_{\mathrm{QSO}}=1.6\pm 0.1$. The observed constraining power of DESI tracers significantly exceeds that of previous large-scale structure (LSS) surveys, and encouragingly, approaches the sensitivity of CMB probes of PNG.