There is evidence that the luminosities of Type Ia supernova (SN Ia) depend on their environments. While the impact of this trend on estimating cosmological parameters is widely acknowledged, the origin of this correlation is still under debate. In order to explore this problem, we first construct the YONSEI (YOnsei Nearby Supernova Evolution Investigation) SN catalog. The catalog consists of 1231 spectroscopically confirmed SNe Ia over a wide redshift range (0.01 < z < 1.37) from various SN surveys and includes light-curve fit data from two independent light-curve fitters, SALT2 and MLCS2k2. For a sample of 674 host galaxies, we use the stellar mass and the star formation rate data in Kim et al. (2018). We find that SNe Ia in low-mass and star-forming host galaxies are 0.062 ± 0.009 mag and 0.057 ± 0.010 mag fainter than those in high-mass and passive hosts, after light-curve corrections with SALT2 and MLCS2k2, respectively. When only local environments of SNe Ia (e.g., locally star-forming and locally passive) are considered, this luminosity difference increases to 0.081 ± 0.018 mag for SALT2 and 0.072 ± 0.018 mag for MLCS2k2. Considering the significant difference in the mean stellar population age between the two environments, this result suggests that the luminosity evolution of SNe Ia with redshift is most likely the origin of the environmental dependence.

Abstract
1. INTRODUCTION
2. THE YONSEI SUPERNOVA CATALOG
    2.1. Datasets
    2.2. Light-Curve Analysis
    2.3. YONSEI Supernova Catalog and Systematic Tests
    2.4. YONSEI Hubble–Lemaiıtre Diagrams
    2.5. Host Galaxy Data
3. SN IA LUMINOSITIES VS. HOST GALAXYPROPERTIES
    3.1. Light-Curve Fit Parameters as Function of HostGalaxy Properties
    3.2. Dependence of SN Ia Luminosities on Host GalaxyProperties
4. ESTIMATING COSMOLOGICAL PARAMETERSFROM SNE IA IN DIFFERENT ENVIRONMENTS
5. DISCUSSION
    5.1. Origin of the Environmental Dependence ofSN Ia Luminosity
    5.2. Luminosity Evolution of SNe Ia?
    5.3. FutureWork
REFERENCES

• Young-Lo Kim(Universit´e de Lyon/Center for Galaxy Evolution Research and Department of Astronomy, Yonsei University) Corresponding author
• Yijung Kang(Center for Galaxy Evolution Research and Department of Astronomy, Yonsei University)
• Young-Wook Lee(Center for Galaxy Evolution Research and Department of Astronomy, Yonsei University)