Detection of extragalactic CF⁺ toward PKS 1830−211

Chemical differentiation in the absorbing gas

¹ Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden
e-mail: mullers@chalmers.se
² Department of Chemistry, Okayama University, Tsushima-naka 3-1-1, Kitaku, 700-8530 Okayama, Japan
³ Department of Chemistry and Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada

Received: 11 March 2016
Accepted: 1 April 2016

Abstract

We report the first extragalactic detection of the fluoromethylidynium ion CF⁺ in the z = 0.89 absorber toward PKS 1830−211. We estimate an abundance of ~3 × 10^-10 relative to H₂ and that ~1% of fluorine is captured in CF⁺. The absorption line profile of CF⁺ is found to be markedly different from that of other species observed within the same tuning, and is notably anticorrelated with CH₃OH. On the other hand, the CF⁺ profile resembles that of [C I]. Our results are consistent with expected fluorine chemistry and point to chemical differentiation in the column of absorbing gas.