Finding the brightest cosmic beacons in the Southern Hemisphere. (arXiv:1909.06391v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+G%2E_C/0/1/0/all/0/1">Calderone G.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+K%2E_B/0/1/0/all/0/1">Boutsia K.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+S%2E_C/0/1/0/all/0/1">Cristiani S.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+A%2E_G/0/1/0/all/0/1">Grazian A.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+R%2E_A/0/1/0/all/0/1">Amorin R.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+V%2E_D/0/1/0/all/0/1">D'Odorico V.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+G%2E_C/0/1/0/all/0/1">Cupani G.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+F%2E_F/0/1/0/all/0/1">Fontanot F.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+M_S/0/1/0/all/0/1">Salvato M</a>
The study of absorptions along the lines of sight to bright high-$z$ QSOs is
an invaluable cosmological tool that provides a wealth of information on the
inter-/circum-galactic medium, Dark Matter, primordial elements, reionization,
fundamental constants, and General Relativity. Unfortunately, the number of
bright ($i lesssim$ 18) QSOs at $z gtrsim 2$ in the Southern hemisphere is
much lower than in the North, due to the lack of wide multi-wavelength surveys
at declination $delta <$ 0$^circ$, hampering the effectiveness of
observations from southern observatories. In this work we present a new method
based on Canonical Correlation Analysis to identify such objects, taking
advantage of a number of available databases: Skymapper, Gaia DR2, WISE, 2MASS.
Our QSO candidate sample lists 1476 sources with $i < 18$ over 12,400 square
degrees in the southern hemisphere. With a preliminary campaign we observed
spectroscopically 70 of them, confirming 56 new bright QSOs at $z > 2.5$,
corresponding to a success rate of our method of $sim$ 80%. Furthermore, we
estimate a completeness of $sim$ 90% of our sample at completion of our
observation campaign. The new QSOs confirmed by this first and the forthcoming
campaigns will be the targets of subsequent studies using higher resolution
spectrographs, like ESPRESSO, UVES, and (in the long term) ELT/HIRES.
The study of absorptions along the lines of sight to bright high-$z$ QSOs is
an invaluable cosmological tool that provides a wealth of information on the
inter-/circum-galactic medium, Dark Matter, primordial elements, reionization,
fundamental constants, and General Relativity. Unfortunately, the number of
bright ($i lesssim$ 18) QSOs at $z gtrsim 2$ in the Southern hemisphere is
much lower than in the North, due to the lack of wide multi-wavelength surveys
at declination $delta <$ 0$^circ$, hampering the effectiveness of
observations from southern observatories. In this work we present a new method
based on Canonical Correlation Analysis to identify such objects, taking
advantage of a number of available databases: Skymapper, Gaia DR2, WISE, 2MASS.
Our QSO candidate sample lists 1476 sources with $i < 18$ over 12,400 square
degrees in the southern hemisphere. With a preliminary campaign we observed
spectroscopically 70 of them, confirming 56 new bright QSOs at $z > 2.5$,
corresponding to a success rate of our method of $sim$ 80%. Furthermore, we
estimate a completeness of $sim$ 90% of our sample at completion of our
observation campaign. The new QSOs confirmed by this first and the forthcoming
campaigns will be the targets of subsequent studies using higher resolution
spectrographs, like ESPRESSO, UVES, and (in the long term) ELT/HIRES.
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