相关论文: A high-redshift quasar absorber without CIV - a ga…

We investigate the physical processes occuring in the multiphase gas of a damped Ly\alpha system (DLA). We base our analysis on a high quality Keck HIRES spectrum of the QSO J1211+0422 in which a DLA is detected at z=2.377. There is little…

We compare the properties of a sample of local (z=0) gas-rich galaxies studied in 21 cm emission to a sample of 13 low-redshift (z < 1) damped Lyman alpha (DLA) galaxies identified as the counterparts of low-redshift DLA systems found in…

The metallicity in portions of high-redshift galaxies has been successfully measured thanks to the gas observed in absorption in the spectra of quasars, in the Damped Lyman-alpha systems (DLAs). Surprisingly, the global mean metallicity…

We test the galactic outflow model by probing associated galaxies of four strong intergalactic CIV absorbers at $z=5$--6 using the Hubble Space Telescope (HST) ACS ramp narrowband filters. The four strong CIV absorbers reside at $z=5.74$,…

We present VLT-UVES echelle spectroscopy of the HI and CIV absorption in the spatially-extended Lyman-alpha emission around two high-redshift radio galaxies 0200+015 (z=2.23) and 0943-242 (z=2.92). The absorbers in 0943-242 exhibit little…

We report on the detection of a z_gal=0.101 galaxy projected on the sky at 4.2 arcsec (or 5.2 h^{-1} kpc for q_o=0.5) from the quasar Q 0439-433 (z_em=0.594). The HST spectrum of the quasar shows strong MgII, FeII, SiII, AlII and CIV…

We report the detection of redshifted HI~21cm absorption in the $z \sim 2.347$ damped Lyman-$\alpha$ absorber (DLA) towards PKS B0438-436, with the Green Bank Telescope. This is the second-highest redshift at which 21cm absorption has been…

We searched for 21-cm absorption associated with the z_abs = 1.3647 absorption system toward PKS 0237-233 using the GMRT. A high quality UVES spectrum shows that C I and C I* are detected at this redshift together with C II*, Mg I, Mg II,…

(Abridged) We have discovered a strong DLA coincident in redshift with the faint QSO Q2343-BX415 (R = 20.2, z_em = 2.57393). Follow-up observations at intermediate spectral resolution reveal that the metal lines associated with this…

We report the first discovery of a QSO damped Ly-alpha (DLA) system by the GALEX satellite. The system was initially identified as an MgII absorption-line system (z_abs=1.028) in the spectrum of SDSS QSO J0203-0910 (z_em=1.58). The presence…

We present a detailed analysis of the H_2 and HD absorption lines detected in the Damped Lyman-alpha (DLA) system at z_abs=2.3377 towards the quasar Q1232+082. We show that this intervening cloud has a covering factor smaller than unity and…

Absorbers seen in the spectrum of background quasars are a unique tool to select HI-rich galaxies at all redshifts. In turns, these allow to determine the cosmological evolution of the HI gas, Omega_HI+HeII, a possible indicator of gas…

We continue our recent work to characterize the plasma content of high-redshift damped and sub-damped Lyman-alpha systems (DLAs/sub-DLAs), which represent multi-phase gaseous (proto)galactic disks and halos seen toward a background source.…

We present the discovery of the optical afterglow of GRB 050505 and an optical absorption spectrum obtained with the Keck I 10-m telescope. The spectrum exhibits three redshifted absorption systems with the highest, at z=4.2748, arising in…

To fully exploit the potential of quasars as probes of cosmic chemical evolution and the internal gas dynamics of galaxies it is important to understand the selection effects behind the quasar samples and in particular if the selection…

We present the results of three separate searches for HI 21-cm absorption in a total of twelve damped Lyman-alpha absorption systems (DLAs) and sub-DLAs over the redshift range z = 0.86-3.37. We find no absorption in the five systems for…

We present a sample of 33 damped Lyman alpha systems (DLAs) discovered in the Sloan Digital Sky Survey (SDSS) whose absorption redshifts (z_abs) are within 6000 km/s of the QSO's systemic redshift (z_sys). Our sample is based on 731 2.5 <…

Using the Atacama Large Millimeter/sub-millimeter Array, we have detected CO(3-2) line and far-infrared continuum emission from a galaxy associated with a high-metallicity ([M/H] = -0.27) damped Ly-alpha absorber (DLA) at z =2.19289. The…

We report results from a deep search for redshifted HI 21cm absorption from eight damped Lyman-$\alpha$ absorbers (DLAs) detected in our earlier optical survey for DLAs towards radio-loud quasars. HI 21cm absorption was detected from the $z…

An extremely careful separation of the weak metal-line systems relating to the Lyman forest absorbers into individual ``single-phase ionization'' components with accurate parameters has yielded a large sample in the wide redshift range 1.9…