High matter density peaks from UVES observations of
 QSO pairs: Correlation properties and chemical
 abundances

D’Odorico, V.; Petitjean, P.; Cristiani, S.

doi:10.1051/0004-6361:20020737

Cited by 49 publications

(40 citation statements)

References 61 publications

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“…iii) QSO B0307-195A and B separated by ∼1 arcmin. A sub-DLA (at z = 1.788 with log N H I = 19.00 ± 0.10) along the line-of-sight of QSO B0307-195B is detected (D'Odorico et al 2002), but is not seen in its companion. iv) QSO J1039-2719 and QSO B1038-2712 separated by 17.9 .…”

Section: Lines-of-sight Of Interestmentioning

confidence: 95%

The ESO UVES advanced data products quasar sample

Zafar

Popping

Péroux

2013

A&A

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We present here a dataset of quasars observed with the Ultraviolet Visual Echelle Spectrograph (UVES) on the Very Large Telescope and available in the European Southern Observatory UVES Advanced Data Products archive. The sample is made up of a total of 250 high resolution quasar spectra with emission redshifts ranging from 0.191 ≤ z em ≤ 6.311. The total UVES exposure time of this dataset is 1560 h. Thanks to the high resolution of UVES spectra, it is possible to unambiguously measure the column density of absorbers with damping wings, down to N H I 10 19 cm −2 , which constitutes the sub-damped Lyα absorber (sub-DLA) threshold. Within the wavelength coverage of our UVES data, we find 150 damped Lyα systems (DLAs)/sub-DLAs in the range 1.5 < z abs < 4.7. Of these 150, 93 are DLAs and 57 are sub-DLAs. An extensive search in the literature indicates that 6 of these DLAs and 13 of these sub-DLAs have their N H I measured for the first time. Among them, 10 are new identifications as DLAs/sub-DLAs. For each of these systems, we obtain an accurate measurement of the H i column density and the absorber's redshift in the range 1.7 < z abs < 4.2 by implementing a Voigt profile-fitting algorithm. These absorbers are further confirmed thanks to the detection of associated metal lines and/or lines from members of the Lyman series. In our data, a few quasars' lines-of-sight are rich. An interesting example is towards QSO J0133+0400 (z em = 4.154) with six DLAs and sub-DLAs reported.

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Section: Lines-of-sight Of Interestmentioning

confidence: 95%

The ESO UVES advanced data products quasar sample

Zafar

Popping

Péroux

2013

A&A

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“…A full presentation of the data reduction is given in a parallel paper focussed on a study of nitrogen abundances in DLAs (Centurión et al 2003). More details on UVES studies of the systems at z = 2.812 in QSO 0528−2505 and z = 2.431 in QSO 2343+1232 can be found in Péroux et al (2003) and D'Odorico et al (2002), respectively. The column densities have been derived with the Voigt-profile fitting routines FITLYMAN (Fontana & Ballester 1995) implemented in the MIDAS software package.…”

Section: The Datamentioning

confidence: 99%

$\ion{Ar}{i}$ as a tracer of ionization evolution

Vladilo

Centurión

D’Odorico

et al. 2003

A&A

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Abstract. We present a study of Ar abundances in 15 damped Ly α systems (DLAs) in the redshift interval 2.3 ≤ z ≤ 3.4. The sample includes 4 UVES/VLT measurements of Ar  column densities presented here for the first time, together with 6 measurements and 5 upper/lower limits collected from the literature (UVES/VLT and HIRES/Keck observations). The majority of DLAs show significant underabundances of Ar relative to other α-capture elements with common nucleosynthetic origin. We show that neither dust depletion nor intervening H  regions inside DLAs offer a viable justification to these underabundances. A natural explanation is found in the framework of photoionization models of H  regions embedded in an ionizing continuum with varying spectral distribution. At z ∼ 2.5 the observed Ar deficiencies are large, [Ar/α] −0.6/ − 0.8 dex, suggestive of a hard, QSO-dominated spectrum. At z > ∼ 3 the deficiencies are instead small, suggestive of a soft, stellar-type spectrum, though more data are needed to generalize this high-z result. Should the change of Ar abundances with redshift be governed by the evolution of the UV stellar emission internal to DLAs, a synchronization of the star formation in DLAs would be required, with a strong stellar emission at z > 3, but weak at z < 3. This variation seems inconsistent with the weak signal of evolution indicated by abundance studies of DLAs. More likely, the change of Ar abundances is induced by the evolution of the UV metagalactic continuum, in which case the UV emission internal to DLAs must be small (i.e. DLAs should have modest star formation rates) and the external background must become softer at z > 3. The former requirement is consistent with the modest evolution of DLAs abundances and the lack of Ly α and H α emissions associated with DLAs. The latter requirement is consistent with the observed evolution of Si /C  ratios in the IGM, the claims of high escape fraction of UV photons from Ly-break galaxies at z > ∼ 3, and the recent finding that the He  re-ionization seems to occur between z ∼ 3.4 and z ∼ 3. Comparison with results from local interstellar studies indicates that Ar abundances can be used to trace the evolution of the ionization history of the universe down to z = 0, where [Ar/α] ∼ −0.2 dex. We predict a rise of Ar abundances in the redshift range from z 2.3 to z = 0, at the epoch at which the metagalactic field of galaxies overcomes that of quasars.

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“…The system shows at least two components and the CIV λ1548−1550 doublet, SiII λ1260, SiIII λ1206 and FeII λ2382 transitions are observed in addition to a strong log(N HI ) > 15 Lyα. Coincidences of absorption systems on scales up to several arcminutes (D'Odorico et al 2002) are observed in the spectra of quasars as the signature of spatial correlation of high density peaks. In the present case the distance between the galaxy HDF-S 1432 and the absorber, 6.2 arcmin, corresponds to 3.1 proper Mpc and is suggestive of a large scale structure at z ∼ 2, which would be extremely interesting to further investigate by carrying out the identification of Lyman-break galaxies in correspondence of the HDF-S STIS field.…”

Section: High Redshift Galaxiesmentioning

confidence: 99%

A VLT/FORS2 spectroscopic survey in the HDF-S

Vanzella

Cristiani

Arnouts

et al. 2002

A&A

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Abstract. We report on low-resolution multi-object spectroscopy of 65 objects from I(AB) 20 to I(AB) 25 in the HDF-S obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS2). 18 objects belong to the HDF-S proper, i.e. the WFPC2 deep area. 15 high-redshift galaxies with 2.0 < z < 3.5 (10 in the HDF-S proper) have been identified. The spectroscopic redshifts are in good agreement with the photometric ones derived from a χ 2 minimization technique comparing the observed spectral energy distribution with synthetic libraries and with a new neural network (NN) approach. The dispersion with the former method is σ z = 0.16 whereas the latter provides σ z = 0.13. No "catastrophic" difference is encountered. The inferred star formation rates of the individual objects range from tens to a few hundreds of M yr −1 and the global star formation rate of the Universe at < z > 2.4 is estimated to be 0.15 M yr −1 Mpc −3 with a statistical error of 0.04. Evidence for large-scale structure is found with two groups' redshifts observed at z 2.1 and z 2.7 and a pronounced low redshift peak around z 0.58. An elliptical galaxy lensing a background object turns out to be at a redshift z = 0.577.

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High matter density peaks from UVES observations of QSO pairs: Correlation properties and chemical abundances

Cited by 49 publications

References 61 publications

The ESO UVES advanced data products quasar sample

The ESO UVES advanced data products quasar sample

$\ion{Ar}{i}$ as a tracer of ionization evolution

A VLT/FORS2 spectroscopic survey in the HDF-S

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