Quasar Unsupervised Encoder and Synthesis Tool

The trained network faithfully reproduces the input spectrum, both in terms of sample median and variance. By examining the latent space, we find correlations with, among others, continuum and bolometric luminosity, black hole mass, redshift, continuum slope, and emission line properties. When used to generate photometry, we find results in excellent agreement with the control sample.

The model provides satisfactory results in reconstructing emission lines: estimates of the black hole mass from the reconstructed spectra are in good agreement with those from the original SDSS spectra. Furthermore, when spectra with broad absorption line features are reconstructed, the model successfully interpolates over the absorption systems. Compared with previous work, we find excellent agreement between the spectra sampled from our model and the output of their results.

However, QUEST does not require any ad-hoc tuning, and is capable of reproducing the full variety of spectra available in the training set.