Carnegie Supernova Project: kinky $i$-band light-curves of Type Ia supernovae

We present detailed investigation of a specific $i$-band light-curve feature in Type Ia supernovae (SNe Ia) using the rapid cadence and high signal-to-noise ratio light-curves obtained by the Carnegie Supernova Project. The feature is present in most SNe Ia and emerges a few days after the $i$-band...

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Hauptverfasser: Pessi, P. J, Hsiao, E. Y, Folatelli, G, Anderson, J. P, Burns, C. R, Uddin, S, Galbany, L, Phiilips, M. M, Morrell, N, Ashall, C, Baron, E, Contreras, C, Hamuy, M, Hoeflich, P, Krisciunas, K, Kumar, S, Lu, J, Martinez, L, Piro, A. L, Shahbandeh, M, Stritzinger, M. D, Suntzeff, N. B
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Sprache:eng
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Zusammenfassung:We present detailed investigation of a specific $i$-band light-curve feature in Type Ia supernovae (SNe Ia) using the rapid cadence and high signal-to-noise ratio light-curves obtained by the Carnegie Supernova Project. The feature is present in most SNe Ia and emerges a few days after the $i$-band maximum. It is an abrupt change in curvature in the light-curve over a few days and appears as a flattening in mild cases and a strong downward concave shape, or a "kink", in the most extreme cases. We computed the second derivatives of Gaussian Process interpolations to study 54 rapid-cadence light-curves. From the second derivatives we measure: 1) the timing of the feature in days relative to $i$-band maximum; tdm$_{2}$($i$) and 2) the strength and direction of the concavity in mag d$^{-2}$ ; dm$_{2}$($i$). 76$\%$ of the SNe Ia show a negative dm$_{2}$($i$), representing a downward concavity - either a mild flattening or a strong "kink". The tdm$_{2}$($i$) parameter is shown to correlate with the color-stretch parameter s$_{\mathrm{BV}}$, a SN Ia primary parameter. The dm$_{2}$($i$) parameter shows no correlation with s$_{\mathrm{BV}}$ and therefore provides independent information. It is also largely independent of the spectroscopic and environmental properties. Dividing the sample based on the strength of the light-curve feature as measured by dm$_{2}$($i$), SNe Ia with strong features have a Hubble diagram dispersion of 0.107 mag, 0.075 mag smaller than the group with weak features. Although larger samples should be obtained to test this result, it potentially offers a new method for improving SN Ia distance determinations without shifting to more costly near-infrared or spectroscopic observations.
DOI:10.48550/arxiv.2112.03122