Establish a reliable optical–NIR flux calibration

Establish a reliable relative flux calibration between the +333-day near-infrared spectrum and the +359-day optical spectrum of SN 2023bee so that the late-time near-infrared spectrum can be included in analyses requiring an accurate absolute flux scale.

Background

The paper combines optical and near-infrared spectroscopy of SN 2023bee to constrain stripped hydrogen and helium and to measure iron-group emission-line ratios. The +333-day FIRE near-infrared spectrum has substantial uncertainties below 10,000 Å, while the +359-day LRIS optical spectrum is used as the principal late-time optical reference.

Because the authors could not establish a reliable relative calibration between these spectra, they excluded the +333-day near-infrared spectrum from analyses dependent on an accurate absolute flux scale. A more reliable calibration would permit the late-time near-infrared data to provide additional constraints on the explosion and progenitor scenario.

References

On the other hand, owing to the large uncertainties in the overlapping region of the +333 day NIR spectrum below 10000\AA, we were unable to establish a reliable relative flux calibration with the +359 day optical spectrum.

— Constraints on the Progenitor of SN 2023bee from its Nebular-Phase Spectra  (2610.25674 - Coelln et al., 19 Oct 2026) in Section 2.2, “Spectroscopic flux calibration”