Spectroscopic QUasar extractor and redshift (z) estimator squeze – II. Universality of the results

• Published in: Monthly notices of the Royal Astronomical Society 2020-08, Vol.496 (4), p.4941-4950
• Main Authors: Pérez-Ràfols, Ignasi, Pieri, Matthew M
• Format: Article
• Language: English
• Subjects: Physics
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/staa1786

ABSTRACT In this paper, we study the universality of the results of squeze, a software package to classify quasar spectra and estimate their redshifts. The code is presented in Pérez-Ràfols et al. (2019). We test the results against changes in signal to noise, spectral resolution, wavelength coverage, and quasar brightness. We find that squeze levels of performance (quantified with purity and completeness) are stable to spectra that have a noise dispersion four times that of our standard test sample, Baryon Oscillation Spectroscopic Survey (BOSS). We also find that the performance remains unchanged if pixels of width 25 Å are considered, and decreases by $\sim 2{{\ \rm per\ cent}}$ for pixels of width 100 Å. We see no effect when analysing subsets of different quasar brightness, and we establish that the blue part (up to 7000 Å) of the spectra is sufficient for the classification. Finally, we compare our suite of tests with samples of spectra expected from WEAVE-QSO and DESI, and narrow-band imaging from J-PAS. We conclude that squeze will perform similarly when confronted with the demands of these future surveys as when applied to current BOSS data.