Modelling intergalactic low ionisation metal absorption line systems near the epoch of reionization

Research output: Contribution to journalArticlepeer-review


We interpret observations of intergalactic low ionization metal absorption systems at redshifts z ≳ 5 in terms of pressure-confined clouds. We find clouds confined by the expected pressure of galactic haloes with masses 11<logMh/h−1M⊙<12 provide a good description of the column density ratios between low ionization metal absorbers. Some of the ratios, however, require extending conventional radiative transfer models of irradiated slabs to spherical (or cylindrical) clouds to allow for lines of sight passing outside the cores of the clouds. Moderate depletion of silicon on to dust grains is also indicated in some systems. The chemical abundances inferred span the range between solar and massive-star-dominated stellar populations as may arise in starburst galaxies. The typical H i column densities matching the data correspond to damped Ly α absorbers (DLAs) or sub-DLAs, with sizes of 40 pc to 3 kpc, gas masses 3.5 < log Mc/M⊙ < 8 and metallicites 0.001−0.01Z⊙⁠. Such systems continue to pose a challenge for galaxy-scale numerical simulations to reproduce
Original languageEnglish
Pages (from-to)888-903
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date16 Jan 2021
Publication statusPublished - 1 Mar 2021


  • astro-ph.CO
  • astro-ph.GA


Dive into the research topics of 'Modelling intergalactic low ionisation metal absorption line systems near the epoch of reionization'. Together they form a unique fingerprint.

Cite this