ZTF SN Ia DR2: Peculiar velocities’ impact on the Hubble diagram

Year: 2025

Type: article

Abstract: Type Ia supernovae (SNe Ia) are used to determine the distance-redshift relation and build the Hubble diagram. Neglecting their host-galaxy peculiar velocities (PVs) may bias the measurement of cosmological parameters. The smaller the redshift, the larger the effect is. We used realistic simulations of SNe Ia observed by the Zwicky Transient Facility (ZTF) to investigate the effect of different methods of taking PVs into account. We studied the impact of neglecting galaxy PVs and their correlations in an analysis of the SNe Ia Hubble diagram. We find that it is necessary to use the PV full covariance matrix computed from the velocity power spectrum to take the sample variance into account. Considering the results we have obtained using simulations, we determine the PV systematic effects in the context of the ZTF SN Ia DR2 sample. We determine the PV impact on the intercept of the Hubble diagram, aB, which is directly linked to the measurement of H0. We show that not taking into account PVs and their correlations results in a shift in the H0 value of about 1.0 km s−1 Mpc−1 and a slight underestimation of the H0 error bar.

Source: Springer Link (Chiba Institute of Technology)

DOI: 10.1051/0004-6361/202450389/pdf

Authors: B. Carreres, D. Rosselli, J. E. Bautista, F. Feinstein, D. Fouchez, B. Racine, C. Ravoux, B. Sanchez, G. Dimitriadis, A. Goobar, J. Johansson, J. Nordin, M. Rigault, M. Smith, M. Amenouche, M. Aubert, C. Barjou-Delayre, U. Burgaz, W. D’Arcy Kenworthy, T. De Jaeger, S. Dhawan, L. Galbany, M. Ginolin, D. Kuhn, M. Kowalski, T. E. Müller-Bravo, P. E. Nugent, B. Popovic, P. Rosnet, F. Ruppin, J. Sollerman, J. H. Terwel, A. Townsend, S. L. Groom, S. R. Kulkarni, J. Purdum, B. Rusholme, N. Sravan

Institutions: Centre National de la Recherche Scientifique, Duke University, Aix-Marseille Université, Centre de physique des particules de Marseille, Institut National de Physique Nucléaire et de Physique des Particules, Université Clermont Auvergne, Laboratoire de Physique de Clermont Auvergne, Trinity College Dublin, Stockholm University, Humboldt-Universität zu Berlin, Lyon 1 Université, Institut de Physique des 2 Infinis de Lyon, Lancaster University, Herzberg Institute of Astrophysics, National Research Council Canada, Laboratoire de Physique Nucléaire et de Hautes Énergies, Institute of Astronomy, Institute of Space Sciences, Deutsches Elektronen-Synchrotron DESY, Lawrence Berkeley National Laboratory, University of California, Berkeley, Nordic Optical Telescope, California Institute of Technology, Infrared Processing and Analysis Center, University of Cambridge, Drexel University

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Awards: Charting new physics with time-domain astronomy, G1855990336, The SED Machine: an Efficient Transient Classifier, G2018370741, G2064873908, G2262748287, G2309174360, G2601397997, Exploring & Exploiting the Dynamic Optical Sky, G2849891921, G3005324705, G300979063, G3010527862, G3439265645, G3480869486, ZWICKY TRANSIENT FACILITY, G3518538256, G3681454997, G4042783231, G425668148, G430777504, Type Ia supernovae: from explosions to cosmology, G4881091899, G5077476177, G5080475149, G5421974903, Understanding Type Ia SuperNovae for Accurate Cosmology, G5805502524, G6159765138, G617610489, G6513613686, G6853635150, G7099350353, G7137047011, G7169023097, G7476612352, GREAT: Gravitational Radiation and Electromagnetic Astrophysical Transients, G8324017279, DEEP Learning For Large Deep Imaging Programs, G8511709958, G8775481269, A golden nearby SN sample from the Zwicky Transient Facility-II Survey (ZTF-II), G8924351487, G917015191

OpenAlex ID: W6959572480