Related papers: HD Molecular Lines in an Absorption System at Reds…
Absorption lines at high redshift in front of quasars are rare in the mm domain. Only five associated and five intervening systems have been reported in the literature. These bring very useful information complementary to emission lines,…
We report on the detection of deuterated molecular hydrogen, HD, at $z = 0.18$. HD and H$_{\rm 2}$ are detected in HST/COS data of a low metallicity ($Z \sim 0.07Z_\odot$) damped Ly$\alpha$ system at $z = 0.18562$ toward QSO B0120$-$28,…
We review observations of molecular absorption line systems at high redshift toward red quasars and gravitational lenses.
A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…
An independent analysis of the molecular hydrogen absorption system at z = 2.059 in the spectrum of the quasar J2123-0050 is presented. The H_2 system consists of two components (A and B) with column densities log N^A(H_2) = 17.94+/-0.01…
New millimeter wave observations of the molecular absorption line system in the gravitational lens to PKS1830-211 at z=0.88582 is presented. Self-calibrated interferometer data shows unequivocally that the previously detected absorption…
We describe initial results of a search for redshifted molecular absorption toward four millimetre-loud, optically faint quasars. A wide frequency bandwidth of up to 23 GHz per quasar was scanned using the Swedish-ESO Sub-millimetre…
Molecular absorption lines measured along the line of sight of distant quasars are important probes of the gas evolution in galaxies as a function of redshift. A review is made of the handful of molecular absorbing systems studied so far,…
Molecular hydrogen is an important component of galaxies because it fuels star formation and accretion onto AGN, the two processes that generate the large infrared luminosities of gas-rich galaxies. Observations of spectral-line emission…
Molecular line emission from high-redshift galaxies holds great promise for the study of galaxy formation and evolution. The weak signals can only be detected with the largest mm-wave telescopes, such as the IRAM interferometer. We report…
We present Giant Metrewave Radio Telescope (GMRT) observations of OH absorption in B3~1504+377 ($z \sim 0.673$) and PKS 1413+135 ($z \sim 0.247$). OH has now been detected in absorption towards four intermediate redshift systems, viz. the…
Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. Here we describe scans towards 7 quasars over wide bandwidths…
Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS1830-211. Obtaining average radial velocities and performing Large Velocity Gradient…
We have undertaken a search for millimetre-wave band absorption (through the CO and HCO+ rotational transitions) in the host galaxies of reddened radio sources (z = 0.405-1.802). Despite the colour selection (optical-near infrared colours…
We present an analysis of the absorption-line system in the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph spectrum at a redshift of $z_{\rm a}={3.1448}$ associated with the quasar SDSS J122040.23+092326.96, whose…
We have searched for molecular absorption lines at millimeter wavelengths in eleven gravitational lens systems discovered in the JVAS/CLASS surveys of flat spectrum radio sources. Spectra of only one source 1030+074 were obtained in the 3-,…
We report the discovery of an unambiguous, substantial low-energy cutoff in the broad band X-ray spectrum of the radio quasar RXJ1028.6-0844 at a redshift of 4.276 obtained with the ASCA satellite, which we preferably explained as…
We list and analyze H I absorption lines at redshifts 2 < z < 4 with column density (12 < log(N_HI) < 19) in 40 high-resolutional (FWHM = 8.0 km/s) quasar spectra obtained with the Keck+HIRES. We de-blend and fit all H I lines within 1,000…
A new molecular hydrogen cloud has been identified at z = 3.025 in the absorption-line spectrum of the quasar 0347-3819 observed with the UVES spectrograph at the VLT/Kueyen telescope. At the same redshift numerous metal lines and the DI…
Absorption lines of H$_2$ and HD molecules observed at high redshift in the line of sight towards quasars are a test ground to search for variation of the proton-to-electron mass ratio $\mu$. For this purpose, results from astronomical…