Universität zu Köln

Muller, S., Mueller, H. S. P., Black, J. H., Gerin, M., Combes, F., Curran, S., Falgarone, E., Guelin, M., Henkel, C., Martin, S., Menten, K. M., Roueff, E., Aalto, S., Beelen, A., Wiklind, T. and Zwaan, M. A. (2017). Detection of CH+, SH+, and their C-13- and S-34-isotopologues toward PKS 1830-211. Astron. Astrophys., 606. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

The z = 0.89 molecular absorber toward PKS 1830-211 provides us with the opportunity to probe the chemical and physical properties of the interstellar medium in the disk of a galaxy at a look-back time of half the present age of the Universe. Recent ALMA observations of hydrides have unveiled the multi-phase composition of this source's interstellar medium along two absorbing sightlines. Here, we report ALMA observations of CH+ and SH+, and of their C-13- and S-34-isotopologues, as potential tracers of energetic processes in the interstellar medium. CH+ and (CH+)-C-13 are detected toward both images of PKS 1830-211, CH+ showing the deepest and broadest absorption among all species observed so far. The [CH+]/[(CH+)-C-13] abundance ratio is similar to 100 in the south-west line of sight. This value is larger than any previous [(CX)-C-12]/[(CX)-C-13] ratios determined from other species toward this source and suggests either that the latter might be affected by fractionation or that CH+ might be tracing a different gas component. Toward the north-east image, we find an even larger value of [CH+]/[(CH+)-C-13], 146 +/- 43, although with a large uncertainty. This sightline intercepts the absorber at a larger galactocentric radius than the southwestern one, where material might be less processed in stellar nucleosynthesis. In contrast to CH+ and its C-13 isotopologue, SH+ and (SH+)-S-34 are only detected on the south-west sightline. These are the first detections of extragalactic SH+ and interstellar (SH+)-S-34. The spectroscopic parameters of SH+ are reevaluated and improved rest frequencies of (SH+)-S-34 are obtained. The [CH+]/[SH+] column density ratios show a large difference between the two lines of sight: similar to 25 and > 600 toward the SW and NE image, respectively. We are not able to shed light on the formation process of CH+ and SH+ with these data, but the differences between the two sightlines toward PKS 1830-211 suggest that their absorptions arise from gas with a molecular fraction of greater than or similar to 10%, with SH+ tracing significantly higher molecular fractions than CH+.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Muller, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, H. S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Black, J. H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gerin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Combes, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Curran, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Falgarone, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Guelin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Henkel, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Martin, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menten, K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Roueff, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Aalto, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Beelen, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wiklind, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zwaan, M. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-214060
DOI:	10.1051/0004-6361/201731405
Journal or Publication Title:	Astron. Astrophys.
Volume:	606
Date:	2017
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MOLECULAR ABSORPTION; INTERSTELLAR-MEDIUM; GRAVITATIONAL LENS; TRANSITION-PROBABILITIES; ROTATIONAL SPECTRUM; COLOGNE DATABASE; SPIRAL GALAXY; REDSHIFT 0.9; SPECTROSCOPY; PKS-1830-211 Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/21406