J/ApJ/887/268 Bright QSOs in Southern Hemisphere (QUBRICS) (Calderone+, 2019)
Finding the brightest cosmic beacons in the southern hemisphere.
Calderone G., Boutsia K., Cristiani S., Grazian A., Amorin R., D'Odorico V.,
Cupani G., Fontanot F., Salvato M.
<Astrophys. J., 887, 268 (2019)>
=2019ApJ...887..268C 2019ApJ...887..268C
ADC_Keywords: QSOs; Surveys; Spectra, optical; Redshifts; Photometry, RI;
Intergalactic medium
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. δ<0°,
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.
Our QSO candidate sample lists 1476 sources with i<18 over 12400deg2
in the southern hemisphere. With a preliminary campaign we observed
spectroscopically 69 of them, confirming 54 new bright QSOs at z>2.5,
corresponding to a success rate of our method of ∼80%. Furthermore, we
estimate a completeness of ∼90% of our sample at completion of our
observation campaign. The new QSOs confirmed by this first and the
forthcoming campaigns (QUBRICS survey) will be the targets of
subsequent studies using higher resolution spectrographs, like
ESPRESSO, UVES, and (in the long term) ELT/HIRES.
Description:
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; 4000-10000Å 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 3700-8000Å.
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
(∼3700-9300Å).
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).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 85 66 List of SkyMapper sources in the candidate sample
observed in our campaigns
table4.dat 85 67 List of SkyMapper sources observed in our campaigns
that are not in the final candidate sample
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See also:
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)
Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- ID [175107/317598139] SkyMapper identifier
11 A1 --- f_ID Flag on ID (1)
13- 14 I2 h RAh Hour of right ascension (J2000)
16- 17 I2 min RAm Minute of right ascension (J2000)
19- 23 F5.2 s RAs Second of right ascension (J2000)
25 A1 --- DE- Sign of declination (J2000)
26- 27 I2 deg DEd Degree of declination (J2000)
29- 30 I2 arcmin DEm Arcminute of declination (J2000)
32- 36 F5.2 arcsec DEs Arcsecond of declination (J2000)
38- 48 A11 "Y:M:D" Date Date of observation (UT)
50- 55 F6.3 mag imag [14.8/18.1] SkyMapper i-band magnitude
57- 60 A4 --- OT Object type ("QSO", "AGN", "STAR", "GAL"
or "???" )
62- 67 F6.4 --- zspec [0.006/4.9]? Spectroscopic redshift
69- 79 A11 --- Inst Instrument (2)
81- 85 A5 --- Note Note
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Note (1): Flag as follows:
a = Also observed by Schindler et al. (2019, J/ApJS/243/5).
b = Also reported by Wang et al. (2016, J/ApJ/819/24).
c = Also observed by Wolf et al. (2020MNRAS.491.1970W 2020MNRAS.491.1970W).
d = Not included in the main sample since the Skymapper i magnitude is
fainter than i=18. Also observed by Schindler+ (2019, J/ApJS/243/5)
and Wolf+ (2020MNRAS.491.1970W 2020MNRAS.491.1970W).
e = Not included in the main sample since the Skymapper astrometric position
differs more than 0.5" from Gaia DRS2 (see the text).
Note (2): Instrument as follows:
IMACS = IMACS on the 6.5m Magellan Baade telescope located at
Las Campanas Observatory, Chile
LDSS-3 = LDSS-3 on the 6.5m Magellan Clay telescope located at
Las Campanas Observatory, Chile
NTT = The ESO 3.5m New Technology Telescope (NTT)
WFCCD = The Wide Field CCD (WFCCD) blue grism on the Du Pont telescope
TNG-Dolores = The Low Resolution Spectrograph (Dolores) on the Italian
Telescopio Nazionale Galileo (TNG) operated on the island of
La Palma.
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Nomenclature notes:
Objects from SkyMapper (II/358) are in Simbad.
History:
From electronic version of the journal
References:
Boutsia et al. Paper II. 2020ApJS..250...26B 2020ApJS..250...26B Cat. J/ApJS/250/26
(End) Prepared by Emmanuelle Perret [CDS] 18-Feb-2021