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OH+ and H2O+ absorption toward PKS 1830-211

Sebastien Muller (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium) ; H. S. P. Müller ; John H. Black (Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik) ; A. Beelen ; F. Combes ; Stephen Curran ; M. Gérin ; M. Guélin ; C. Henkel ; S. Martín ; Susanne Aalto (Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik) ; E. Falgarone ; K. M. Menten ; P. Schilke ; Tommy Wiklind ; M. A. Zwaan
Astronomy and Astrophysics (0004-6361). Vol. 595 (2016), p. A128(1-10).
[Artikel, refereegranskad vetenskaplig]

We report the detection of OH+ and H2O+ in the z = 0.89 absorber toward the lensed quasar PKS 1830-211. The abundance ratio of OH+ and H2O+ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic hydrogen (ζH) along two lines of sight, located at 2 kpc and 4 kpc to either side of the absorber's center. The molecular fraction decreases outward, from 0.04 to 0.02, comparable to values measured in the Milky Way at similar galactocentric radii. For ζH , we find values of 2 × 10-14 s-1 and 3 × 10-15 s-1, respectively, which are slightly higher than in the Milky Way at comparable galactocentric radii, possibly due to a higher average star formation activity in the z = 0.89 absorber. The ALMA observations of OH+, H2O+, and other hydrides toward PKS 1830-211reveal the multi-phase composition of the absorbing gas. Taking the column density ratios along the southwest and northeast lines of sight as a proxy of molecular fraction, we classify the species ArH+, OH+, H2Cl+, H2O+, CH, and HF as tracing gases increasingly more molecular. Incidentally, our data allow us to improve the accuracy of H2O+ rest frequencies and thus refine the spectroscopic parameters.

Nyckelord: quasars, quasar absorption lines, galaxies: abundances, interstellar molecules

Denna post skapades 2016-12-22. Senast ändrad 2017-01-13.
CPL Pubid: 246488


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Institutioner (Chalmers)

Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium (2010-2017)
Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik (2010-2017)


Extragalaktisk astronomi

Chalmers infrastruktur

Onsala rymdobservatorium