The spectroscopic follow-up of the QUBRICS bright quasar survey
  We present the results of the spectroscopic follow up of the QUBRICS survey.
The selection method is based on a machine learning approach applied to
photometric catalogs, covering an area of $\sim$ 12,400 deg$^2$ in the Southern
Hemisphere. The spectroscopic observations started in 2018 and identified 55
new, high-redshift (z>=2.5), bright (i<=18) QSOs, with the catalog published in
late 2019. Here we report the current status of the survey, bringing the total
number of bright QSOs at z<=2.5 identified by QUBRICS to 224. The success rate
of the QUBRICS selection method, in its most recent training, is estimated to
be 68%. The predominant contaminant turns out to be lower-z QSOs at z<2.5. This
survey provides a unique sample of bright QSOs at high-z available for a number
of cosmological investigations. In particular, carrying out the redshift drift
measurements (Sandage Test) in the Southern Hemisphere, using the HIRES
spectrograph at the 39m ELT, appears to be possible with less than 2500 hours
of observations spread over 30 targets in 25 years.
