3D Correlations in the Lyman-$\alpha$ Forest from Early DESI Data

• Main Authors: Gordon, Calum, Cuceu, Andrei, Chaves-Montero, Jonás, Font-Ribera, Andreu, González-Morales, Alma Xochitl, Aguilar, J, Ahlen, S, Armengaud, E, Bailey, S, Bault, A, Brodzeller, A, Brooks, D, Claybaugh, T, de la Cruz, R, Dawson, K, Doel, P, Forero-Romero, J. E, Gontcho, S. Gontcho A, Guy, J, Herrera-Alcantar, H. K, Iršič, V, Karaçaylı, N. G, Kirkby, D, Landriau, M, Guillou, L. Le, Levi, M. E, de la Macorra, A, Manera, M, Martini, P, Meisner, A, Miquel, R, Montero-Camacho, P, Muñoz-Gutiérrez, A, Napolitano, L, Nie, J, Niz, G, Palanque-Delabrouille, N, Percival, W. J, Pieri, M, Poppett, C, Prada, F, Pérez-Ràfols, I, Ramírez-Pérez, C, Ravoux, C, Rezaie, M, Ross, A. J, Rossi, G, Sanchez, E, Schlegel, D, Schubnell, M, Seo, H, Sinigaglia, F, Tan, T, Tarlé, G, Walther, M, Weaver, B. A, Yèche, C, Zhou, Z, Zou, H
• Format: Journal Article
• Language: English
• Published: 21.08.2023
• Subjects: Physics - Cosmology and Nongalactic Astrophysics
• DOI: 10.48550/arxiv.2308.10950

We present the first measurements of Lyman-$\alpha$ (Ly$\alpha$) forest correlations using early data from the Dark Energy Spectroscopic Instrument (DESI). We measure the auto-correlation of Ly$\alpha$ absorption using 88,509 quasars at $z>2$, and its cross-correlation with quasars using a further 147,899 tracer quasars at $z\gtrsim1.77$. Then, we fit these correlations using a 13-parameter model based on linear perturbation theory and find that it provides a good description of the data across a broad range of scales. We detect the BAO peak with a signal-to-noise ratio of $3.8\sigma$, and show that our measurements of the auto- and cross-correlations are fully-consistent with previous measurements by the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). Even though we only use here a small fraction of the final DESI dataset, our uncertainties are only a factor of 1.7 larger than those from the final eBOSS measurement. We validate the existing analysis methods of Ly$\alpha$ correlations in preparation for making a robust measurement of the BAO scale with the first year of DESI data.