"Supernovae Ia Twins" in the Hubble Flow, and the Determination of H<SUB>0</SUB>

Ruiz-Lapuente, P.; Quintana-Estellés, A.; González Hernández, J. I.; Pastorello, A.
Bibliographical reference

The Astrophysical Journal

Advertised on:
7
2026
Number of authors
4
IAC number of authors
1
Citations
1
Refereed citations
0
Description
We have applied our approach of using "supernovae (SNe) Ia twins" in the Hubble flow to obtain distances to SNe Ia at z > 0.015 and derive H0. Our results, taking a single step between the low-z domain and the Hubble flow, validate the three-rung classical method. We find, however, that the full compilation of distances, both in Pantheon+ and in the Carnegie-Chicago Hubble Program (CCHP), contains some inaccurate values in the colors due to an underestimate of reddening by dust, or due to the adoption of not well-defined light curve declines. This produces odd individual values for H0 from single SNe Ia. On average, those erroneous estimates do not affect the mean value of H0, which is characterized by the bulk of well-modeled SNe Ia. Our sample of carefully addressed SNe Ia in the Hubble flow contains a dozen SNe, for which the distances are determined with high accuracy. Three of these SNe Ia are of the broad-line subtype and can be compared with SN 1989B in M66, a host galaxy with a unique convergence of the Cepheid distance determination and the tip of the red giant branch stars determination by the CCHP group. There is also a very good agreement on the distances to NGC 7250 and NGC 5643 between those derived with Cepheids by SH0ES and those derived with the use of J-asymptotic giant branch (JAGB) stars by the CCHP, which makes them very good anchors. The sample of 12 SNe Ia gives a value of H0 = 72.56 ± 1.54 (stat) ± 1.33 (sys) km s−1 Mpc −1, when anchored in Cepheids, and of H0 = 72.20 ± 1.53 (stat) ± 1.33 (sys) km s−1 Mpc −1, when anchored in JAGB stars by the CCHP. We take a mean of the two values of H0 as derived by the Cepheids and by JAGB stars (from the CCHP) and obtain H0 = 72.38 ± 1.54 (stat) ± 1.33 (sys) km s−1 Mpc −1. Our findings confirm that the Hubble tension is real.