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Interactive Explorer for Lu et al. 2023 NIR Spectral Templates of Type Ia Supernovae

This page explores the near-infrared spectral template for Type Ia supernovae from Lu et al. 2023, built with BYOST from 339 Carnegie Supernova Project II FIRE spectra. Unlike a one-parameter sequence, the template is a function of two quantities: rest-frame epoch relative to B-band maximum, and the color-stretch parameter s_BV.

Pin a baseline (epoch, s_BV) pair — the starting point is the median of the training sample — then watch how the spectrum responds when one parameter is swept while the other stays fixed. The 2-D histogram shows where the CSP-II NIR spectroscopic sample actually covers that parameter plane.

Spectra below are reconstructed from the published principal components and ONNX-serialised Gaussian-process weights shipped with BYOST, then stored as a dense interpolation grid so every update stays in the browser. No data is sent to a server.

1. Baseline model

The 2-D histogram shows where the CSP-II NIR spectroscopic sample covers the (epoch, s_BV) plane, with 1-D histograms along the top and right. Drag the red line on either histogram (or type a value) to move the baseline; the comparison plots update immediately. Click the map to set both parameters at once.

2. Varying one parameter

The first panel holds epoch at the baseline and sweeps s_BV. The second panel holds s_BV at the baseline and sweeps epoch. Both axes are logarithmic. The black line is the baseline spectrum; its legend lists the current epoch and s_BV.