TY - JOUR
T1 - Modelling the impact of quasar redshift errors on the full-shape analysis of correlations in the Lyman-α forest
AU - Gordon, Calum
AU - Cuceu, Andrei
AU - Font-Ribera, Andreu
AU - Herrera-Alcantar, Hiram K.
AU - Aguilar, Jessica Nicole
AU - Ahlen, Steven
AU - Bianchi, Davide
AU - Brooks, David
AU - Claybaugh, Todd
AU - Cole, Shaun
AU - Macorra, Axel de la
AU - Dey, Biprateep
AU - Doel, Peter
AU - Forero-Romero, Jaime E.
AU - Gaztañaga, Enrique
AU - Gontcho, Satya Gontcho A
AU - Gutierrez, Gaston
AU - Guy, Julien
AU - Honscheid, Klaus
AU - Ishak, Mustapha
AU - Kehoe, Robert
AU - Kirkby, David
AU - Kisner, Theodore
AU - Kremin, Anthony
AU - Landriau, Martin
AU - Guillou, Laurent Le
AU - Levi, Michael
AU - Manera, Marc
AU - Martini, Paul
AU - Miquel, Ramon
AU - Moustakas, John
AU - Nadathur, Seshadri
AU - Niz, Gustavo
AU - Palanque-Delabrouille, Nathalie
AU - Percival, Will
AU - Prada, Francisco
AU - Pérez-Ràfols, Ignasi
AU - Rossi, Graziano
AU - Sanchez, Eusebio
AU - Schlegel, David
AU - Schubnell, Michael
AU - Seo, Hee-Jong
AU - Silber, Joseph Harry
AU - Sprayberry, David
AU - Tarlé, Gregory
AU - Weaver, Benjamin Alan
AU - Zhou, Rongpu
AU - Zou, Hu
N1 - 19 pages, 12 figures
PY - 2026/1/1
Y1 - 2026/1/1
N2 - In preparation for the first cosmological measurements from the full shape of the Lyman- (Ly ) forest from Dark Energy Spectroscopic Instrument (DESI), we must carefully model all relevant systematics that might bias our analysis. It has been shown that random quasar redshift errors produce a smoothing effect on the mean quasar continuum in the Ly forest region. This, in turn, gives rise to spurious features in the Ly autocorrelation and its cross-correlation with quasars. Using synthetic data sets based on the DESI survey, we confirm that the impact on baryon acoustic oscillation measurements is small, but that a bias is introduced to parameters which depend on the full shape of our correlations. We combine a model of this contamination in the cross-correlation with a new model we introduce here for the autocorrelation. These are parametrized by three parameters, which, when included in a joint fit to both correlation functions, successfully eliminate any impact of redshift errors on our full-shape constraints. We also present a strategy for removing this contamination from real data, by removing 0.3 per cent of correlating pairs.
AB - In preparation for the first cosmological measurements from the full shape of the Lyman- (Ly ) forest from Dark Energy Spectroscopic Instrument (DESI), we must carefully model all relevant systematics that might bias our analysis. It has been shown that random quasar redshift errors produce a smoothing effect on the mean quasar continuum in the Ly forest region. This, in turn, gives rise to spurious features in the Ly autocorrelation and its cross-correlation with quasars. Using synthetic data sets based on the DESI survey, we confirm that the impact on baryon acoustic oscillation measurements is small, but that a bias is introduced to parameters which depend on the full shape of our correlations. We combine a model of this contamination in the cross-correlation with a new model we introduce here for the autocorrelation. These are parametrized by three parameters, which, when included in a joint fit to both correlation functions, successfully eliminate any impact of redshift errors on our full-shape constraints. We also present a strategy for removing this contamination from real data, by removing 0.3 per cent of correlating pairs.
KW - astro-ph.CO
KW - dark energy
KW - distance scale
KW - large-scale structure of Universe
U2 - 10.1093/mnras/staf2035
DO - 10.1093/mnras/staf2035
M3 - Article
SN - 0035-8711
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
M1 - staf2035
ER -