Scientific Rationale

The standardized luminosities of Type Ia supernovae (SNe Ia) are known to correlate with several properties of their host galaxies. Among these correlations, the host mass step is now routinely included as an additional empirical correction in the SN magnitude standardization process. However, host galaxy mass itself cannot directly influence the intrinsic luminosity of SNe Ia. This suggests that the mass step reflects a more fundamental physical parameter that correlates with galaxy mass, such as stellar population age or metallicity. In recent years, direct and extensive measurements of SN host galaxy ages, together with complementary observational evidence, have highlighted the role of SN progenitor age as an underlying origin of the reported host-dependent correlations. Identifying the true physical driver of these correlations is crucial because different host properties evolve very differently with redshift, and corrections based on them can therefore lead to significantly different cosmological inferences. At the same time, other cosmological probes, such as DESI BAO, have suggested that dark energy may not be a simple cosmological constant, but could instead evolve with time and possibly weaken at late epochs. In this rapidly changing landscape of observational cosmology, it is timely to re-examine the core assumptions underlying supernova cosmology in light of the latest observational evidence. This workshop aims to provide a focused and constructive forum to reassess the physical foundations of SN Ia luminosity standardization, to discuss its implications for cosmological conclusions, and to explore new directions for precision cosmology with SNe Ia in the LSST era.

Organizing Committee

Chul Chung
Junhyuk Son
Young-Lo Kim
Dongwook Lim
Hyejeon Cho

Inhyuk Park
Seunghyun Park
Suk-Jin Yoon
Young-Wook Lee

Contact us via chulchung@yonsei.ac.kr

Code of Conduct

The workshop enforces the AAS code of ethics policy. Harassment and unprofessional conduct (including the use of offensive language) of any kind are not permitted at any time.