J/MNRAS/456/3509 Optically thin CIII absorbers at z∼2.5 (Kim+, 2016)
Evidence of bimodal physical properties of intervening, optically thin C III
absorbers at z∼2.5.
Kim T.-S., Carswell R.F., Ranquist D.
<Mon. Not. R. Astron. Soc., 456, 3509-3534 (2016)>
=2016MNRAS.456.3509K 2016MNRAS.456.3509K (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Spectroscopy ; Redshifts
Keywords: intergalactic medium - quasars: absorption lines -
cosmology: observations
Abstract:
We present the Voigt profile analysis of 132 intervening CIV+CIII
components associated with optically thin HI absorbers at 2.1<z<3.4 in
the 19 high-quality UVES/VLT and HIRES/Keck QSO spectra. For logNCIV
in [11.7, 14.1], NCIII∝NCIV1.42±0.11 and
<NCIII/NCIV≥1.0±0.3 with a negligible redshift evolution. For 54
CIV components tied (aligned) with HI at logNHI in [12.2, 16.0] and
logNCIV in [11.8, 13.8], the gas temperature Tb estimated from
absorption line widths is well approximated to a Gaussian peaking at
logTb∼4.4±0.3 for logTb in [3.5, 5.5], with a negligible
non-thermal contribution. For 32 of 54 tied HI+CIV pairs, also tied
with CIII at logNCIII in [11.7, 13.8], we ran both photoionization
equilibrium (PIE) and non-PIE (using a fixed temperature Tb) cloudy
models for the Haardt-Madau QSOs+galaxies 2012 UV background. We find
evidence of bimodality in observed and derived physical properties.
High-metallicity branch absorbers have a carbon abundance
[C/H]temp≥-1.0, a line-of-sight length Ltemp≤20kpc and a total
(neutral and ionized) hydrogen volume density lognH,temp in
[-4.5, -3.3] and logTb in [3.9, 4.5]. Low-metallicity branch
absorbers have [C/H]temp≤-1.0, Ltemp in [20, 480]kpc and
lognH,temp in [-5.2, -4.3] and logTb∼ 4.5. High-metallicity branch
absorbers seem to be originated from extended discs, inner haloes or
outflowing gas of intervening galaxies, while low-metallicity
absorbers are produced by galactic haloes or the surrounding
intergalactic medium filament.
Description:
A total of 19 QSO spectra were used to search for CIII, with the 17
spectra taken with the UVES on the VLT and the remaining two spectra
with the HIRES on Keck.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 53 20 Analysed QSOs
table2.dat 76 549 Line lists of individual CIII absorbers
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- QSO QSO name
15- 19 F5.3 --- zem Redshift measured from the observed Lyα
emission line
20 A1 --- n_zem [d] Note on zem (1)
22- 26 F5.3 --- zCIIIl Lower value of CIII redshift interval (2)
27 A1 --- --- [-]
28- 32 F5.3 --- zCIIIu Upper value of CIII redshift interval (2)
34- 36 I3 --- S/NLya ? S/N per pixel in the central parts of the
analysed Lyα forest
37 A1 --- --- [,]
39- 41 I3 --- S/NCIV ? S/N per pixel in the central parts of the
analysed CIV region
42 A1 --- --- [,]
44- 45 I2 --- S/NCIII ? S/N per pixel in the central parts of the
analysed CIII region
47- 51 A5 --- Inst Intrument
53 A1 --- Line [*] * indicates line lists of individual CIII
absorbers in table3.dat
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Note (1): d when the redshift is uncertain due to many absorption lines in the
peak of the Lyα emission line.
Note (2): Only the region with S/N≥5 per pixel is analysed.
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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- 12 A12 --- QSO QSO name
14- 18 A5 --- Ion Ion (1)
20- 26 F7.2 km/s DV Relative velocity
28- 33 F6.2 km/s e_DV rms uncertainty on DV
35- 42 F8.6 --- zabs Absorption redshift
44- 51 F8.6 --- e_zabs rms uncertainty on zabs
53 A1 --- l_b Limit flag on b
54- 59 F6.2 km/s b Linewidth b
61- 65 F5.2 km/s e_b ? rms uncertainty on b
67- 71 F5.2 [cm-2] logN logarithmic column density
73- 76 F4.2 [cm-2] e_logN rms uncertainty on logN
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Note (1): Note that only the reference ion CIV has a VPFIT-estimated error on
redshifts and b, when CIII and/or HI are tied with CIV.
In this case, the errors of the tied parameters of CIII/HI are marked as zero.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Sep-2016