SIMBAD references

2023MNRAS.524.2446B - Mon. Not. R. Astron. Soc., 524, 2446-2459 (2023/September-2)

Carbonates and ices in the z = 0.89 galaxy-absorber towards PKS 1830-211 and within star-forming regions of the Milky Way.


Abstract (from CDS):

A pair of 6.0 and 6.9 μm absorption features are frequently observed in Milky Way (MW) molecular-clouds and YSOs; they also occur in the z = 0.886 rest-frame of a molecule-rich spiral galaxy obscuring blazar PKS 1830-211. I calibrate χ2-fitting methods, which match observations with two or three laboratory spectra. The 6.0-μm component is dominated by H2O ice, as expected. Included MW sources were selected using opacity criteria which limit the range of explored H2O-ice column densities to 1.6-2.4 × 1018 molecules cm–2, while the H2O-ice density in the galaxy absorber is (2.7 ± 0.5) × 1018 molecules cm–2. CH3OH ice and / or small (< 0.1-μm-sized) Ca- and Mg-bearing carbonates contribute at 6.9 μm. The 41 per cent CH3OH:H2O molecular ratio in the PKS 1830-211 absorber is significantly higher than in the molecular cloud towards Taurus-Elias 16 (<7.5 per cent) and similar to the highest value in MW YSOs (35 per cent in AFGL 989). Fitted carbonate (-CO3):H2O ratios in the galaxy absorber of 0.091 per cent are low in comparison to most of the ratios detected in the MW sample (0.2 per cent-0.4 per cent; ∼0 per cent in AFGL 989). Inorganic carbonates could explain the increased oxygen depletion at the diffuse-medium-to-molecular-cloud transition, which Jones and Ysard associated with unobserved organic carbonates or materials with a C:O ratio of 1:3.

Abstract Copyright: © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): Galaxy: abundances - Infrared: ISM - stars: pre-main-sequence - quasars: individual: PKS 1830-211 - solid state: refractory - solid state: volatile

Simbad objects: 23

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