J/MNRAS/462/3285 XQ-100. X-shooter quasar spectra (Perrotta+, 2016)
Nature and statistical properties of quasar associated absorption systems in the
XQ-100 Legacy Survey.
Perrotta S., D'odorico V., Prochaska J.X., Cristiani S., Cupani G.,
Ellison S., Lopez S., Becker G.D., Berg T.A.M., Christensen L.,
Denney K.D., Hamann F., Paris I., Vestergaard M., Worseck G.
<Mon. Not. R. Astron. Soc., 462, 3285-3301 (2016)>
=2016MNRAS.462.3285P 2016MNRAS.462.3285P (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; QSOs ; Spectroscopy ; Redshifts
Keywords: galaxies: high-redshift - intergalactic medium -
quasars: absorption lines
Abstract:
We statistically study the physical properties of a sample of narrow
absorption line (NAL) systems looking for empirical evidences to
distinguish between intrinsic and intervening NALs without taking into
account any a priori definition or velocity cut-off. We analyse the
spectra of 100 quasars with 3.5<zem<4.5, observed with
X-shooter/Very Large Telescope in the context of the XQ-100 Legacy
Survey. We detect an ∼8σ excess in the CIV number density
within 10000km/s of the quasar emission redshift with respect
to the random occurrence of NALs. This excess does not show a
dependence on the quasar bolometric luminosity and it is not due to
the redshift evolution of NALs. It extends far beyond the standard
5000km/s cut-off traditionally defined for associated absorption
lines. We propose to modify this definition, extending the threshold
to 10000km/s when weak absorbers (equivalent width <0.2Å)
are also considered. We infer NV is the ion that better traces the
effects of the quasar ionization field, offering the best statistical
tool to identify intrinsic systems. Following this criterion, we
estimate that the fraction of quasars in our sample hosting an
intrinsic NAL system is 33 per cent. Lastly, we compare the properties
of the material along the quasar line of sight, derived from our
sample, with results based on close quasar pairs investigating the
transverse direction. We find a deficiency of cool gas (traced by C
II) along the line of sight connected to the quasar host galaxy, in
contrast with what is observed in the transverse direction.
Description:
The quasars in our sample have been originally selected and observed
in a new Legacy Survey, hereafter 'XQ-100', of 100 quasars at
emission redshift zem=3.5-4.5 (ESO Large Programme 189.A-0424).
The observations have been carried out with X-shooter/VLT (Vernet et
al., 2011A&A...536A.105V 2011A&A...536A.105V). The released spectra provide a complete
coverage from the atmospheric cut-off to the NIR with a spectral
resolution R∼6000-9000 depending on wavelength, and a median S/N∼30 at
the continuum level. XQ-100 provides the first large
intermediate-resolution sample of high-redshift quasars with
simultaneous rest-frame UV/optical coverage. A full description of the
target selection, observations, and data reduction process is
presented by Lopez et al. (2016A&A...594A..91L 2016A&A...594A..91L).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sources.dat 60 100 XQ-100 targets
table2.dat 132 987 Data for the XQ-100 targets
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Byte-by-byte Description of file: sources.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name of the target
12- 35 A24 --- OName Other name
37- 38 I2 h RAh Right ascension (J2000)
40- 41 I2 min RAm Right ascension (J2000)
43- 47 F5.2 s RAs Right ascension (J2000)
49 A1 --- DE- Declination sign (J2000)
50- 51 I2 deg DEd Declination (J2000)
53- 54 I2 arcmin DEm Declination (J2000)
56- 60 F5.2 arcsec DEs Declination (J2000)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name of the target
12- 17 F6.4 --- zem Emission redshift of the target
19- 24 F6.3 10-7W Lbol Bolometric luminosity of the target
26- 30 F5.3 10-7W e_Lbol Bolometric luminosity error
32- 34 A3 --- RType Radio type (1)
36- 40 F5.3 --- zabs Redshift of the absorbers (NAL)
42- 46 F5.2 [cm-2] logNCIV CIV 1548 column density
48- 51 F4.2 [cm-2] e_logNCIV CIV 1548 column density error
53- 57 F5.3 0.1nm EWCIV CIV 1548 rest-frame equivalent width
59- 63 F5.3 0.1nm e_EWCIV CIV 1548 rest-frame equivalent width error
65- 69 F5.2 [cm-2] logNSiIV ?=0 SiIV 1393 column density
71- 74 F4.2 [cm-2] e_logNSiIV ?=0 SiIV 1393 column density error
76- 80 F5.3 0.1nm EWSiIV ?=0 SiIV 1393 rest-frame equivalent width
82- 86 F5.3 0.1nm e_EWSiIV ?=0 SiIV 1393 rest-frame equivalent width
error
88- 92 F5.2 [cm-2] logNNV ?=0 NV 1238 column density
94- 97 F4.2 [cm-2] e_logNNV ?=0 NV 1238 column density error
99-103 F5.3 0.1nm EWNV ?=0 NV 1238 rest-frame equivalent width
105-109 F5.3 0.1nm e_EWNV ?=0 NV 1238 rest-frame equivalent width error
111-115 F5.2 [cm-2] logNCII ?=0 CII 1334 column density
117-120 F4.2 [cm-2] e_logNCII ?=0 CII 1334 column density error
122-126 F5.3 0.1nm EWCII ?=0 CII 1334 rest-frame equivalent width
128-132 F5.3 0.1nm e_EWCII ?=0 CII 1334 rest-frame equivalent width
error
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Note (1): Radio type as follows:
RL = Radio loud QSO
RQ = Radio quiet QSO
not = target without radio information
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Mar-2018