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Related papers: Molecular Hydrogen in Damped Ly-alpha Systems: Spa…

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We present the discovery of molecular hydrogen (H_2), including the presence of vibrationally-excited H_2^* in the optical spectrum of the afterglow of GRB 120815A at z=2.36 obtained with X-shooter at the VLT. Simultaneous photometric…

We study the dust depletion pattern in eight well separated components of the z=1.973, logN(HI)=20.83, damped Lyman-alpha system toward Q0013-004, four of which have detectable H2 absorption. The apparent correlation between the abundance…

Astrophysics · Physics 2009-11-07 Patrick Petitjean , R. Srianand , Cédric Ledoux

We present the elemental abundance and H2 content measurements of a Damped Lyman-{\alpha} (DLA) system with an extremely large H i column density, log N(H i) (cm-2) = 22.0+/-0.10, at zabs = 3.287 towards the QSO SDSS J 081634+144612. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 R. Guimarães , P. Noterdaeme , P. Petitjean , C. Ledoux , R. Srianand , S. Lopez , H. Rahmani

We study the physical conditions in DLAs, using a sample of 33 systems toward 26 QSOs acquired for a recently completed survey of H_2 by Ledoux et al. (2003). We use the column densities of H_2 in different rotational levels, together with…

Astrophysics · Physics 2009-11-13 Raghunathan Srianand , Patrick Petitjean , Cedric Ledoux , Gary Ferland , Gargi Shaw

We have searched for molecular hydrogen in damped Lyman-alpha (DLA) and sub-DLA systems at z>1.8 using UVES at the VLT. Out of the 33 systems in our sample, 8 have firm and 2 have tentative detections of associated H2 absorption lines.…

Astrophysics · Physics 2009-11-07 C. Ledoux , P. Petitjean , R. Srianand

We present new estimates for the statistical properties of damped Lyman-$\alpha$ absorbers (DLAs). We compute the column density distribution function at $z>2$, the line density, $\mathrm{d}N/\mathrm{d}X$, and the neutral hydrogen density,…

Astrophysics of Galaxies · Physics 2017-01-25 Simeon Bird , Roman Garnett , Shirley Ho

We present the current status of ongoing searches for molecular hydrogen in high-redshift (1.8 < zabs <= 4.2) Damped Lyman-alpha systems (DLAs) capitalising on observations performed with the ESO Very Large Telescope (VLT) Ultraviolet and…

Astrophysics · Physics 2009-11-13 P. Noterdaeme , C. Ledoux , P. Petitjean , R. Srianand

Damped Ly-alpha Systems (DLAs), with N(HI)>2*10^20 cm^{-2}, observed in quasars have allowed us to quantify the chemical content of the Universe over cosmological scales. Such studies can be extended to lower N(HI), in the sub-DLA range…

A new molecular hydrogen cloud is found in the sub-damped Ly-alpha absorber [log N(HI)=19.88+/-0.05] at the redshift z=1.15 toward the bright quasar HE0515-4414 (zem = 1.71). More than 30 absorption features in the Lyman band system of H2…

Astrophysics · Physics 2009-11-10 D. Reimers , R. Baade , R. Quast , S. A. Levshakov

We estimate the abundance of dust in damped Lyman-{\alpha} absorbers (DLAs) by statistically measuring the excess reddening they induce on their background quasars. We detect systematic reddening behind DLA consistent with the SMC type…

Astrophysics of Galaxies · Physics 2015-06-19 Masataka Fukugita , Brice Ménard

We use the Hubble Space Telescope (HST) archive of ultraviolet (UV) quasar spectroscopy to conduct the first blind survey for damped Ly-alpha absorbers (DLAs) at low redshift (z < 1.6). Our statistical sample includes 463 quasars with…

We use state-of-the-art cosmological zoom simulations to explore the distribution of neutral gas in and around galaxies that gives rise to high column density \ion{H}{i} \mbox{Ly-$\alpha$} absorption (formally, sub-DLAs and DLAs) in the…

We present results from a search for strong H2 absorption systems proximate to quasars (zabs~zem) in the Sloan Digital Sky Survey (SDSS) Data Release 14. The search is based on the Lyman-Werner band signature of damped H2 absorption lines…

Astrophysics of Galaxies · Physics 2019-07-03 P. Noterdaeme , S. Balashev , J. -K. Krogager , R. Srianand , H. Fathivavsari , P. Petitjean , C. Ledoux

We report the serendipitous detection of an H$_{2}$-bearing damped Lyman-$\alpha$ absorber at z = 0.576 in the spectrum of the QSO J0111-0316 in the Cosmic Ultraviolet Baryon Survey. Spectroscopic observations from HST-COS in the…

(Abridged) We present the results of a systematic GBT and GMRT survey for 21-cm absorption in a sample of 10 DLAs at 2<z_abs<3.4. Analysis of L-band VLBA images of the background QSOs are also presented. We detect 21-cm absorption in only…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 R. Srianand , N. Gupta , P. Petitjean , P. Noterdaeme , C. Ledoux , C. J. Salter , D. J. Saikia

We present a detailed analysis of a high resolution spectrum of the damped Ly$\alpha$ system at $z_{\rm abs}$~=~2.8112toward PKS~0528-250. The absorption redshift is slightly larger than the emission redshift of the quasar. We estimate the…

Astrophysics · Physics 2007-05-23 R. Srianand , P. Petitjean

We present the detection of the average H$_2$ absorption signal in the overall population of neutral gas absorption systems at $z\sim 3$ using composite absorption spectra built from the Sloan Digital Sky Survey-III damped Lyman-$\alpha$…

Astrophysics of Galaxies · Physics 2018-05-02 Sergei Balashev , Pasquier Noterdaeme

We report results on the incidence and cosmological mass density of damped Lyman-alpha (DLA) systems at redshifts less that 1.65. We used HST and an efficient non-traditional (but unbiased) survey technique to discover DLA systems at…

Astrophysics · Physics 2009-10-31 Sandhya M. Rao , David A. Turnshek

We present results of analysis of physical conditions (number density, intensity of UV field, kinetic temperature) in the cold H$_2$-bearing interstellar medium of local and high redshift galaxies. Our measurements based on the fit to the…

Astrophysics of Galaxies · Physics 2020-10-07 V. V. Klimenko , S. A. Balashev

We present a detailed analysis of a red quasar at z=2.32 with an intervening damped Lyman-alpha absorber (DLA) at z=2.13. Using high quality data from the X-shooter spectrograph at ESO Very Large Telescope we find that the absorber has a…

Astrophysics of Galaxies · Physics 2017-06-19 J. -K. Krogager , J. P. U. Fynbo , P. Noterdaeme , T. Zafar , P. Møller , C. Ledoux , T. Krühler , A. Stockton