Mon, November 17, 2025
1:00 pm - 2:00 pm
PRB 4138
Alberto Rosado Marín (a final-year grad student) is visiting us from Ohio University to give a talk at the Cosmology group meeting (1-2 pm in PRB 4138)
Title: Imaging Systematics Treatment for DESI ELGs and Constraining Primordial non-Gaussianity from DESI
Abstract: Angular imaging systematics can introduce non-trivial, spurious correlations in the observed target density across the sky. The Dark Energy Spectroscopic Instrument (DESI) survey, like other large-scale structure surveys, has an ongoing effort to identify and mitigate such imaging systematics. The emission line galaxy (ELG) sample is most susceptible to imaging systematics and requires non-linear mitigation approaches such as machine learning. However, these mitigation methods must be employed with care, as overfitting can suppress cosmological signal on large scales, compromising key measurements such as primordial non-Gaussianity (PNG). In this talk, I will present an overview of DESI imaging systematics and their impact on two-point clustering statistics, including Baryon Acoustic Oscillation (BAO) measurements. I will also discuss how robust PNG constraints can be achieved using cross-correlations between ELGs, luminous red galaxies (LRGs), and quasars (QSOs).