On the scarcity of redshifted OH and millimetre-band molecular absorption

  title={On the scarcity of redshifted OH and millimetre-band molecular absorption},
  author={Stephen J. Curran},
  journal={Monthly Notices of the Royal Astronomical Society},
  • S. Curran
  • Published 15 September 2021
  • Physics
  • Monthly Notices of the Royal Astronomical Society
Despite much searching, redshifted decimetre- and millimetre-band absorption by molecular gas remains very rare, limited to just six systems at zabs ≳ 0.05. Detection of these transitions can yield precise diagnostics of the conditions of the star-forming gas in the earlier Universe, the hydroxyl (OH) radical being of particular interest as in the λ = 18 cm ground state there are four different transitions located close to neutral hydrogen 21- cm and thus detectable with the Square Kilometre… Expand

Figures and Tables from this paper


  • 2021
A pilot search for extragalactic OH absorption with FAST
OH absorption is currently the only viable way to detect OH molecules in non-masing galaxies at cosmological distances. There have been only 6 such detections at z>0.05 to date and so it is hard toExpand
All good things come in threes: the third image of the lensed quasar PKS 1830−211
Strong gravitational lensing distorts our view of sources at cosmological distances but brings invaluable constraints on the mass content of foreground objects and on the geometry and properties ofExpand
Blind H i and OH Absorption Line Search: First Results with MALS and uGMRT Processed Using ARTIP
We present details of the Automated Radio Telescope Imaging Pipeline (ARTIP) and the results of a sensitive blind search for H i and OH absorbers at z < 0.4 and z < 0.7, respectively. ARTIP isExpand
FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field
We present early science results from the First Large Absorption Survey in HI (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen HI gas at cosmological distancesExpand
New molecular species at redshift z = 0.89.
The first detections of CH3SH, C3H+, C3N, HCOOH, CH2CHCN, and H2CN in an extragalactic source are presented, and the molecular abundances are characteristic of diffuse or translucent clouds with enhanced UV radiation or strong shocks. Expand
The evolution of neutral hydrogen over the past 11 Gyr via H i 21 cm absorption
We present the results of a blind search for intervening HI 21 cm absorption toward 260 radio sources in the redshift range 0<z<2.74 with the Green Bank Telescope. The survey has the sensitivity toExpand
A Search for Intrinsic H i 21 cm and OH 18 cm Absorption toward Compact Radio Sources
We present the results of a large search for intrinsic HI 21 cm and OH 18 cm absorption in 145 compact radio sources in the redshift range 0.02< z <3.8 with the Green Bank Telescope. We re-detect HIExpand
Chlorine-bearing molecules in molecular absorbers at intermediate redshifts
We use observations of chlorine-bearing species in molecular absorbers at intermediate redshifts to investigate chemical properties and 35Cl/37Cl isotopic ratios in the absorbing sightlines.Expand
Ionization of the atomic gas in redshifted radio sources
We report the results of a survey for H I 21-cm absorption at z ≲ 0.4 in a new sample of radio sources with the Giant Metrewave Radio Telescope. Of the 11 sources for which there are good data, weExpand