Back to Search
Start Over
Consistent extinction model for type Ia supernovae in Cepheid-based calibration galaxies and its impact on H0.
- Source :
-
Monthly Notices of the Royal Astronomical Society . Sep2024, Vol. 533 Issue 2, p2319-2334. 16p. - Publication Year :
- 2024
-
Abstract
- The most recent SH0ES measurement of the Hubble constant employs corrections of type Ia supernova magnitudes due to extinction in their host galaxies. These corrections are estimated using a probabilistic model which is trained on Hubble flow (|$z\gt 0.03$|) supernovae and extrapolated to the calibration galaxies (those with observed Cepheids), despite the fact that the latter are selected based on criteria favouring discy and dust-rich systems. We show that this standard approach underestimates the brightness of reddened supernovae in the high stellar-mass (|$M_{\star }\gt 10^{10}\, \mathrm{M}_{\odot }$|) calibration galaxies. This can be traced back to the fact that for these galaxies, a low total-to-selective extinction coefficient (|$R_{\rm B}\sim 3$|) is assumed, while for the low stellar-mass analogues a more standard |$R_{\rm B}\sim 4$| is adopted. We propose a minimalistic modification of the extinction model in the calibration galaxies in order to alleviate this systematic effect. The modification is twofold and it involves: (i) the same, Milky Way-like distribution of |$R_{\rm B}$| (with mean |$R_{\rm B}$| of 4.3 – consistent with the extinction curve used for colour corrections of the Cepheids – and scatter 0.4) and (ii) a modified shape of the |$E(B-V)$| reddening distribution while keeping the same effective slope of the supernova peak magnitude–colour relation and the same mean |$E(B-V)$| reddening as measured for supernovae in the Hubble flow. We show that this new approach yields a significantly better fit (|$\Delta \mathrm{ BIC}=-11$|) to the calibration data and results in a lower value of |$H_{0}$|. Our result is |$H_{0}=70.5\pm 1$|  km s |$^{-1}$|  Mpc |$^{-1}$| implying a reduction of the Hubble constant tension from |$5.2\sigma$| to |$2.8\sigma$|. [ABSTRACT FROM AUTHOR]
- Subjects :
- *TYPE I supernovae
*CEPHEIDS
*SUPERNOVAE
*GALAXIES
*CALIBRATION
*HUBBLE constant
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 533
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 179513373
- Full Text :
- https://doi.org/10.1093/mnras/stae1977