Resolving redshifted molecular absorption toward the gravitational lens PKS 1830-211

Brenda Frye, William J. Welch, Tom Broadhurst

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Using the high-resolution configuration of the BIMA array, we have spatially resolved molecular absorption at z = 0.89 toward the gravitational lens PKS 1830-211. Two continuum sources are detected at λ3 mm separated by 0″.98 at the known positions of the doubly lensed radio core. Broad molecular absorption of width 40 km s-1 is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, despite the large optical depth inferred from the molecular transitions (Wiklind & Combes). This implies incomplete coverage of the southwest component, ∼70%, by the molecular gas, despite the small projected size of the source, less than 8 h-1 pc at the absorption redshift. Similar saturated but unfilled columns of low-density molecular gas are found in absorption through the spiral arms of the Milky Way, with large variations in column depth on parsec scales, indicating that the southwest component of PKS 1830-211 may be occulted by an ordinary spiral arm. At spectral resolution better than 5 km s-1, we might expect the broad molecular absorption of PKS 1830-211 to resolve into multiple narrow lines.

Original languageEnglish (US)
Pages (from-to)L25-L28
JournalAstrophysical Journal
Issue number1 PART II
StatePublished - 1997


  • Galaxies: ISM
  • Galaxies: individual (PKS 1830-211)
  • Gravitational lensing
  • ISM: molecules

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Resolving redshifted molecular absorption toward the gravitational lens PKS 1830-211'. Together they form a unique fingerprint.

Cite this