On the impact of the supernova subsamples in reducing the Hubble tension

Understand

The persistent 4-6$\sigma$ difference between early- and late-time Hubble constant ($H_{0}$) measurements, known as the "Hubble tension", is a major problem in modern cosmology.

• We study how differences in colour ($c$), stretch ($x_{1}$), and host galaxy properties-stellar mass ($M$) and specific star formation rate (sSFR)-between calibration and Hubble Flow (HF) Type Ia supernova (SN Ia) samples used by SH0ES affect SN luminosity standardization and $H_{0}$ estimates.
• We generate subsamples from both, estimating $H_{0}$, $M_{B}$, $\alpha$, $\beta$, $\Delta_{host}$, and $\sigma_{int}$.
• We use Kolmogorov-Smirnov to assess the consistency between subsamples and reveal how parameter estimates change as sample matching improves.