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

From National Research Council Canada

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DOIResolve DOI: https://doi.org/10.1051/0004-6361/202450389
AuthorSearch for: ORCID identifier: https://orcid.org/0000-0002-7234-844X; Search for: ORCID identifier: https://orcid.org/0000-0001-6839-1421; Search for: ORCID identifier: https://orcid.org/0000-0002-9885-3989; Search for: ORCID identifier: https://orcid.org/0000-0001-5548-3466; Search for: ORCID identifier: https://orcid.org/0000-0002-7496-3796; Search for: ORCID identifier: https://orcid.org/0000-0001-8861-3052; Search for: ORCID identifier: https://orcid.org/0000-0002-3500-6635; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0001-9494-179X; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0001-5975-290X; Search for: ORCID identifier: https://orcid.org/0000-0001-8342-6274; Search for: ORCID identifier: https://orcid.org/0000-0002-8121-2560; Search for: ORCID identifier: https://orcid.org/0000-0002-3321-1432; Search for: 1ORCID identifier: https://orcid.org/0009-0006-7454-3579; Search for: ; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0003-0126-3999; Search for: ORCID identifier: https://orcid.org/0000-0002-5153-5983; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0002-2376-6979; Search for: ORCID identifier: https://orcid.org/0000-0002-1296-6887; Search for: ORCID identifier: https://orcid.org/0009-0004-5311-9301; Search for: ORCID identifier: https://orcid.org/0009-0005-8110-397X; Search for: ORCID identifier: https://orcid.org/0000-0001-8594-8666; Search for: ORCID identifier: https://orcid.org/0000-0003-3939-7167; Search for: ORCID identifier: https://orcid.org/0000-0002-3389-0586; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0002-6099-7565; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0003-1546-6615; Search for: ORCID identifier: https://orcid.org/0000-0001-9834-3439; Search for: ORCID identifier: https://orcid.org/0000-0001-6343-3362; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
Affiliation
  1. National Research Council of Canada. Herzberg Astronomy and Astrophysics
FormatText, Article
Subjectdark energy; distance scale; arge-scale structure of Universe
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.
Publication date
PublisherEDP Sciences
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In
  • Astronomy & Astrophysics 694, A8 (14 February 2025).
LanguageEnglish
Peer reviewedYes
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Record identifier0504ebeb-40cd-4d71-9780-59f55ddf49e8
Record created2025-05-14
Record modified2025-05-14
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