Finding the brightest cosmic beacons in the southern hemisphere. (2019)
Keywords :
Quasars ; Sky surveys ; Catalogs
Abstract: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<~18) QSOs at z>~2 in the southern hemisphere is much lower than that in the north, due to the lack of wide multiwavelength surveys at decl. {delta}<0{deg}, 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, and 2MASS.
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We have carried out extensive spectroscopy observations at the Las
Campanas Observatory and at the ESO-NTT telescope at La Silla. The
results of these observations build up the QUBRICS (QUasar BRIllanti
per la Cosmologia nell'emisfero Sud) survey.
The first pilot study was carried out at the Magellan telescopes in
2018 using LDSS-3 (Clay Telescope; 4000-10000{AA} and R~800) and IMACS
(Baade Telescope).
In 2019 February we were awarded 2 nights at the du Pont telescope to
validate the optimized criteria, and we observed several new
candidates with the Wide Field CCD (WFCCD) blue grism that covers a
wavelength range between 3700-8000{AA}.
The NTT spectroscopic campaign has been carried out during the ESO
observing period P103 under the proposal 0103.A-0746 (PI. A. Grazian).
Three nights of spectroscopy have been executed during 2019 April 27-30.
The EFOSC2 instrument was used, equipped with the grism #13
(~3700-9300{AA}).
Finally, in 2019 June we performed a few exposures at the Italian
Telescopio Nazionale Galileo (TNG; operated on the island of La Palma)
using the Low Resolution Spectrograph (Dolores) with the LR-B grism
(resolution ~600).
- I/345 : Gaia DR2 (Gaia Collaboration, 2018)
- II/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)
- VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003)
- VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
- VII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)
- J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
- J/ApJ/819/24 : z>4.5 QSOs with SDSS and WISE. I. Opt. spectra (Wang+, 2016)
- J/AJ/153/107 : Australian Dark Energy Survey (OzDES) QSO cat. (Tie+, 2017)
- J/MNRAS/488/1035 : AGN UV luminosity function (Kulkarni+, 2019)
- J/ApJS/243/5 : The ELQS in the PS1 footprint (PS-ELQS) (Schindler+, 2019)
- J/ApJS/250/26 : Spectroscopic follow-up of the QUBRICS QSOs (Boutsia+, 2020)
