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arXiv · 2609.34508

Field-level inference of growth rate from DESI BGS galaxy and ZTF supernova simulations

Abstract

Galaxy peculiar velocities are a powerful probe of the growth rate of structure $f$ at low redshifts ($z < 0.2$), measured through the combination $fσ_8$. These constraints are improved by combining peculiar velocities with redshift space distortion measurements from the galaxy density field. We create a dedicated simulation to test growth rate measurement from the combination of Type Ia supernova peculiar velocities from the Zwicky Transient Facility (ZTF) with the Bright Galaxy Survey (BGS) of the Dark Energy Spectroscopic Instrument (DESI), using projections for 6 years of ZTF data and the Data Release 3 (DR3) of DESI. We apply a wide-angle likelihood-based field-level inference to combine ZTF velocity and DESI BGS density fields simultaneously. This procedure is performed while varying the different density and velocity field configurations. Adding DESI galaxy density information to the ZTF supernovae improves the constraint on nuisance parameters and yields up to a 50 \% reduction in the growth-rate uncertainty without introducing bias. If we consider the conservatively best DESI density configuration, the mean error bar achievable by a DESI ZTF measurement is $σ_{fσ_8} = {}^{+0.047}_{-0.048}$ corresponding to a 10 \% error. These measurements will play a critical role for testing modified gravity theories.

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Corentin Ravoux, Bastien Carreres, Julian Bautista, Damiano Rosselli, Jessica Aguilar, Steven Ahlen, Melissa Amenouche, Uendert Andrade, Eric Armengaud, Alejandro Aviles, Florian Beutler, Davide Bianchi, David Brooks, Umut Burgaz, Aurelio Carnero Rosell, Edmond Chaussidon, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Georgios Dimitriadis, Andreu Font-Ribera, Daniel Felipe Forero Sánchez, Jaime E. Forero-Romero, Enrique Gaztañaga, Satya Gontcho A Gontcho, Ariel Goobar, Gaston Gutierrez, Hiram K. Herrera-Alcantar, Cullan Howlett, Mustapha Ishak, Joel Johansson, Stephanie Juneau, Ofer Lahav, Martin Landriau, Laurent Le Guillou, Alexie Leauthaud, Marc Manera, Ramon Miquel, Seshadri Nadathur, Jakob Nordin, Hernan Enrique Noriega, Enrique Paillas, Nathalie Palanque-Delabrouille, Will Percival, Francisco Prada, Ignasi Pérez-Ràfols, Mickael Rigault, Antoine Rocher, Philippe Rosnet, Graziano Rossi, Rossana Ruggeri, Lado Samushia, Eusebio Sanchez, Christoph Saulder, David Schlegel, Michael Schubnell, Hee-Jong Seo, Joseph Silber, Małgorzata Siudek, Mathew Smith, Gregory Tarlé, Benjamin A. Weaver, Pauline Zarrouk. 2026-09-28. Field-level inference of growth rate from DESI BGS galaxy and ZTF supernova simulations. https://arxiv.org/abs/2609.34508

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