Luminosity-Dependent Variations in the Secondary Maximum of Type Ia Supernovae and Their Connection to Host Galaxy Morphology

TL;DR

This study investigates how the timing of the secondary maximum in near-infrared light curves of Type Ia supernovae varies with luminosity and host galaxy type, revealing distinct groups that can refine cosmological distance measurements.

Contribution

It identifies a luminosity-dependent structure in the secondary maximum timing and links it to host galaxy morphology, enhancing supernova calibration methods.

Findings

Secondary maximum timing varies with luminosity.

Distinct groups of SNe Ia linked to host galaxy type.

Implications for improved cosmological distance calibration.

Abstract

Type Ia supernovae (SNe Ia) are considered standardizable candles and are therefore important probes of the universe's expansion history and cosmic distances. In comparison to the optical and IR photometric observations, NIR light curves of SNe Ia are more uniform and are less affected by dust extinction; hence, they can provide more precise distance estimates. This study examines the relationship between the luminosity-dependent behavior of the NIR secondary maximum ($t_2$) and the decline rate parameter ($\Delta m_{15}$) in the B Band. We analyzed 54 SNe Ia using linear, piecewise linear regression, and non-linear models along with non-parametric statistical techniques to examine the correlation between $t_2$ and $\Delta m_{15}$. Our results show that the secondary maximum timing varies among SNe Ia but exhibits a luminosity-dependent structure, with significant differences between SNe hosted in late and early-type galaxies. Two separate groups belonging to different host morphologies have been identified through our analysis, one containing brighter SNe and the other containing fainter SNe. These findings have important implications for improving the calibration of SNe Ia for cosmological applications.