Unconfirmed Hα emission in outburst spectra

Determine whether Hα emission is present in the low-resolution outburst spectra of AT2022kak obtained with SALT and KOALA and quantify its properties (e.g., equivalent width and line profile).

Background

Time-resolved, low-resolution spectra during the 2025 outburst show Balmer absorption features consistent with dwarf novae. Typical dwarf nova outburst spectra may exhibit Hα emission, but the signal-to-noise ratio in these data is insufficient for confirmation.

Confirming or ruling out Hα emission would clarify the accretion disc state and emission-line behavior during the outburst, informing classification and physical interpretation.

References

The low-resolution 2025 outburst spectra collected by SALT and KOALA show Balmer absorption lines, which are expected for DNe, however the SNR is too low to confirm weak Hα emission (Figures \ref{fig:koala_spectra_and_features} and \ref{fig:salt_spectra}).

— An extremely fast fading population II dwarf nova candidate: caught spectroscopically on the rise (2510.26682 - Bemmel et al., 30 Oct 2025) in Section 4.2 (Spectral Analysis)