Comment on the recent claims of H0 measurements with the ZTF DR2 SN Ia sample (arXiv:2610.36051)

Mickael Rigault; Brodie Popovic; Ariel Goobar; Suhail Dhawan; Marie Aubert; Marc Betoule; Umut Burgaz; Georgios Dimitriadis; Lluís Galbany; Tomás E. Müller Bravo; Antoine Gilles Lordet; Madeleine Ginolin; Young-Lo Kim; Marek Kowalski; Jakob Nordin; Nicolas Regnault; Mathew Smith; Jesper Sollerman; Jacco H. Terwel; Alice Townsend

arXiv · 2611.07794

Comment on the recent claims of H0 measurements with the ZTF DR2 SN Ia sample (arXiv:2610.36051)

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Abstract

Karchev et al. (2026) derived a value of H0 by combining the ZTF SN Ia DR2 sample with SH0ES calibrator Type Ia supernovae (SNe Ia; Riess et al. 2022), used to anchor the SN Ia absolute luminosity. The ZTF SN Ia DR2 dataset (Rigault et al., 2025) is the largest (O(3000)) SN Ia sample to date obtained with a single telescope. However, as emphasized in the data release, the absolute photometric calibration of the survey has not yet been established to the precision required for cosmological inference. The relative photometric zeropoint offset between the SH0ES and ZTF SN Ia DR2 samples, which is fully degenerate with H0, is therefore unknown and cannot be determined from publicly available data. The photometric corrections introduced in Karchev et al. (2026) do not address this global calibration offset. Consequently, their reported H0 determination is not supported by the available calibration information. We nonetheless share the excitement of pursuing state-of-the-art cosmology with ZTF and are actively working toward the release of a fully calibrated dataset

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Mickael Rigault, Brodie Popovic, Ariel Goobar, Suhail Dhawan, Marie Aubert, Marc Betoule, Umut Burgaz, Georgios Dimitriadis, Lluís Galbany, Tomás E. Müller Bravo, Antoine Gilles Lordet, Madeleine Ginolin, Young-Lo Kim, Marek Kowalski, Jakob Nordin, Nicolas Regnault, Mathew Smith, Jesper Sollerman, Jacco H. Terwel, Alice Townsend. 2026-11-05. Comment on the recent claims of H0 measurements with the ZTF DR2 SN Ia sample (arXiv:2610.36051). https://arxiv.org/abs/2611.07794

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