Modelling the impact of quasar redshift errors on the full-shape analysis of correlations in the Lyman-α forest
ABSTRACT In preparation for the first cosmological measurements from the full shape of the Lyman-$\alpha$ (Ly $\alpha$) 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 $\alpha$ forest region. This, in turn, gives rise to spurious features in the Ly $\alpha$ 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 $\sim$0.3 per cent of correlating pairs.
Authors
- D. Kirkby (ORCID: https://orcid.org/0000-0002-8828-5463)
- Will J. Percival (ORCID: https://orcid.org/0000-0002-0644-5727)
- Rongpu Zhou (ORCID: https://orcid.org/0000-0001-5381-4372)
- Paul Martini (ORCID: https://orcid.org/0000-0002-4279-4182)
- Michael S. Schubnell (ORCID: https://orcid.org/0000-0001-9504-2059)
- Graziano Rossi (ORCID: https://orcid.org/0000-0002-5102-5019)
- N. Palanque‐Delabrouille (ORCID: https://orcid.org/0000-0003-3188-784X)
- S. Nadathur (ORCID: https://orcid.org/0000-0001-9070-3102)
- H. K. Herrera-Alcantar (ORCID: https://orcid.org/0000-0002-9136-9609)
- Gregory Tarlé (ORCID: https://orcid.org/0000-0003-1704-0781)
- Andreu Font-Ribera (ORCID: https://orcid.org/0000-0002-3033-7312)
- Laurent Le Guillou (ORCID: https://orcid.org/0000-0001-7178-8868)
- David Sprayberry (ORCID: https://orcid.org/0000-0001-7583-6441)
- Gustavo Niz (ORCID: https://orcid.org/0000-0002-1544-8946)
- D. Bianchi (ORCID: https://orcid.org/0000-0001-9712-0006)
- David J. Schlegel (ORCID: https://orcid.org/0000-0002-5042-5088)
- Ignasi Pérez-Ràfols (ORCID: https://orcid.org/0000-0001-6979-0125)
- Axel de la Macorra (ORCID: https://orcid.org/0000-0002-1769-1640)
- Martin Landriau (ORCID: https://orcid.org/0000-0003-1838-8528)
- Shaun Cole (ORCID: https://orcid.org/0000-0002-5954-7903)
- M. E. Levi (ORCID: https://orcid.org/0000-0003-1887-1018)
- Gaston Gutierrez (ORCID: https://orcid.org/0000-0003-0825-0517)
- Eusebio Sanchez (ORCID: https://orcid.org/0000-0002-9646-8198)
- Satya Gontcho A Gontcho (ORCID: https://orcid.org/0000-0003-3142-233X)
- ENRIQUE GAZTAÑAGA (ORCID: https://orcid.org/0000-0001-9632-0815)
- Andrei Cuceu (ORCID: https://orcid.org/0000-0002-2169-0595)
- Joseph Harry Silber (ORCID: https://orcid.org/0000-0002-3461-0320)
- J. E. Forero-Romero (ORCID: https://orcid.org/0000-0002-2890-3725)
- R. Miquel (ORCID: https://orcid.org/0000-0002-6610-4836)
- Theodore S. Kisner (ORCID: https://orcid.org/0000-0003-3510-7134)
- Biprateep Dey (ORCID: https://orcid.org/0000-0002-5665-7912)
- David H. Brooks (ORCID: https://orcid.org/0000-0002-2189-9313)
- John Moustakas (ORCID: https://orcid.org/0000-0002-2733-4559)
- Mustapha Ishak (ORCID: https://orcid.org/0000-0002-6024-466X)
- Hee‐Jong Seo (ORCID: https://orcid.org/0000-0002-6588-3508)
- Peter Doel
- Hu Zou (ORCID: https://orcid.org/0000-0002-6684-3997)
- T. Claybaugh (ORCID: https://orcid.org/0000-0002-5024-6987)
- Julien Guy
- Marc Manera
- Benjamin A. Weaver
- R. Kehoe
- Klaus Honscheid
- F. Prada (ORCID: https://orcid.org/0000-0001-7145-8674)
- Jessica Nicole Aguilar Steven Ahlen
- C. Gordon (ORCID: https://orcid.org/0000-0003-2561-5733)
Institutions
- Boston University (US)
- Institució Catalana de Recerca i Estudis Avançats (ES)
- Universidad Complutense de Madrid (ES)
- Universitat Autònoma de Barcelona (ES)
- Centre National de la Recherche Scientifique (FR)
- Universidad de Guanajuato (MX)
- Fermi National Accelerator Laboratory (US)
- Institute of Space Sciences (ES)
- Lawrence Berkeley National Laboratory (US)
- University of Waterloo (CA)
- State Street (United States) (US)
- Universidad de Los Andes (CO)
- The University of Texas at Dallas (US)
- University of Pittsburgh (US)
- Southern Methodist University (US)
- Perimeter Institute (CA)
- Institute for High Energy Physics (ES)
- University of Milan (IT)
- Durham University (GB)
- Chinese Academy of Sciences (CN)
- University of California, Irvine (US)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Université Paris-Saclay (FR)
- University of Michigan (US)
- Institut d'Astrophysique de Paris (FR)
- Brera Astronomical Observatory (IT)
- Sejong University (KR)
- Sorbonne Université (FR)
- Institut d'Estudis Espacials de Catalunya (ES)
- Laboratoire de Physique Nucléaire et de Hautes Énergies (FR)
- Ohio University (US)
- Canadian Institute for Theoretical Astrophysics (CA)
- CEA Paris-Saclay (FR)
- Institut National de Physique Nucléaire et de Physique des Particules (FR)
- Community Science and Data Center (US)
- Istituto Nazionale di Fisica Nucleare, Sezione di Milano (IT)
- Centro de Investigación en Materiales Avanzados (MX)
- NSF NOIRLab (US)
- Universidad de Los Andes (BO)
- Instituto de Astrofísica de Andalucía (ES)
- National Astronomical Observatories (CN)
- Institut de Recherche sur les Lois Fondamentales de l'Univers (FR)
- Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES)
- University College London (GB)
- The Ohio State University (US)
- University of Portsmouth (GB)
- Universidad Nacional Autónoma de México (MX)
- Siena College (US)
- Universitat Politècnica de Catalunya (ES)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2025-11-22
- DOI
- https://doi.org/10.1093/mnras/staf2035
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00