Year: 2025
Type: article
Abstract: ABSTRACT Optical galaxy cluster identification algorithms such as redMaPPer promise to enable an array of astrophysical and cosmological studies, but suffer from biases whereby galaxies in front of and behind a galaxy cluster are mistakenly associated with the primary cluster halo. These projection effects caused by irreducible photometric redshift uncertainty must be quantified to facilitate the use of optical cluster catalogues. We present measurements of galaxy cluster projection effects and velocity dispersion using spectroscopy from the Dark Energy Spectroscopic Instrument. Our findings are as follows: we confirm that the fraction of redMaPPer putative member galaxies mistakenly associated with cluster haloes is richness dependent, being more than twice as large at low richness than high richness; we present the first spectroscopic evidence of an increase in projection effects with increasing redshift, by as much as 25 per cent from $z\sim 0.1$ to $z\sim 0.2$; moreover, we find qualitative evidence for luminosity dependence in projection effects, with fainter galaxies being more commonly far behind clusters than their bright counterparts; finally, we fit the scaling relation between measured mean spectroscopic richness and velocity dispersion, finding an implied linear scaling between spectroscopic richness and halo mass. We discuss further directions for the application of spectroscopic data sets to improve use of optically selected clusters to test cosmological models.
Authors: J Myles, D Gruen, T Jeltema, A Mantz, S Allen, S Fu, A Kremin, J Aguilar, S Ahlen, D Bianchi, D Brooks, F J Castander, T Claybaugh, A de la Macorra, Arjun Dey, P Doel, S Ferraro, J E Forero-Romero, E Gaztañaga, S Gontcho A Gontcho, G Gutierrez, K Honscheid, M Ishak, R Kehoe, D Kirkby, T Kisner, O Lahav, M Landriau, L Le Guillou, M Manera, A Meisner, R Miquel, J Moustakas, S Nadathur, J A Newman, N Palanque-Delabrouille, F Prada, I Pérez-Ràfols, G Rossi, E Sanchez, D Schlegel, M Schubnell, J Silber, D Sprayberry, G Tarlé, B A Weaver, R Zhou
Institutions: Princeton University, Excellence Cluster Origins, Ludwig-Maximilians-Universität München, University of California, Santa Cruz, SLAC National Accelerator Laboratory, Stanford University, Lawrence Berkeley National Laboratory, Boston University, University of Milan, Brera Astronomical Observatory, National Institute for Astrophysics, University College London, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Universitat Politècnica de Catalunya, Universidad Nacional Autónoma de México, NSF NOIRLab, University of California, Berkeley, Universidad de Los Andes, University of Portsmouth, University of Virginia, Fermi National Accelerator Laboratory, The Ohio State University, The University of Texas at Dallas, Southern Methodist University, University of California, Irvine, Centre National de la Recherche Scientifique, Sorbonne Université, Laboratoire de Physique Nucléaire et de Hautes Énergies, Institut National de Physique Nucléaire et de Physique des Particules, Universitat Autònoma de Barcelona, Institute for High Energy Physics, Barcelona Institute of Science and Technology, Institució Catalana de Recerca i Estudis Avançats, Siena College, University of Pittsburgh, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, CEA Paris-Saclay - Etablissement de Saclay, Institut de Recherche sur les Lois Fondamentales de l'Univers, Instituto de Astrofísica de Andalucía, Sejong University, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, University of Michigan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funders: National Science Foundation, U.S. Department of Energy, Alfred P. Sloan Foundation, Gordon and Betty Moore Foundation, Brinson Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, New York University, Ohio State University, University of Utah, University of Washington, Johns Hopkins University, University of Arizona, Carnegie Mellon University, University of Notre Dame, University of Virginia, University of Portsmouth, New Mexico State University, National Energy Research Scientific Computing Center, York University, University of Oxford, Ministério da Ciência, Tecnologia e Inovação, University of Tokyo, Ministerio de Ciencia e Innovación, Universidad Nacional Autónoma de México, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Office of Science, University of Colorado Boulder, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, Leibniz-Gemeinschaft, Division of Astronomical Sciences, Lawrence Berkeley National Laboratory
Awards: G1044631029, G1079818582, G1143651532, G122673668, G1286236842, G1677143136, G1813527838, G1863003419, G419881185, G42916606, G4501827968, G498139845, G5004724115, G5076365615, G6652958823, G6876926712, G7146827954, Management and Operations of the National Optical Astronomy Observatory, G7354628648
OpenAlex ID: W4411339685