Revised spectroscopic parameters of SH$^+$ from ALMA and IRAM 30 m observations

Holger S. P. Müller Javier R. Goicoechea 1 José Cernicharo 2 M. Agúndez Jérôme Pety 1, 3 Sara Cuadrado Maryvonne Gerin 1 Gaelle Dumas 3 E. Chapillon 4, 3
4 AMOR 2014
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : Hydrides represent the first steps of interstellar chemistry. Sulfanylium (SH$^+$), in particular, is a key tracer of energetic processes. We used ALMA and the IRAM 30 m telescope to search for the lowest frequency rotational lines of SH$^+$ toward the Orion Bar, the prototypical photo-dissociation region illuminated by a strong UV radiation field. On the basis of previous $Herschel$/HIFI observations of SH$^+$, we expected to detect emission of the two SH$^+$ hyperfine structure (HFS) components of the $N_J = 1_0 - 0_1$ fine structure (FS) component near 346 GHz. While we did not observe any lines at the frequencies predicted from laboratory data, we detected two emission lines, each $\sim$15 MHz above the SH$^+$ predictions and with relative intensities and HFS splitting expected for SH$^+$. The rest frequencies of the two newly detected lines are more compatible with the remainder of the SH$^+$ laboratory data than the single line measured in the laboratory near 346 GHz and previously attributed to SH$^+$. Therefore, we assign these new features to the two SH$^+$ HFS components of the $N_J = 1_0 - 0_1$ FS component and re-determine its spectroscopic parameters, which will be useful for future observations of SH$^+$, in particular if its lowest frequency FS components are studied. Our observations demonstrate the suitability of these lines for SH$^+$ searches at frequencies easily accessible from the ground.
Type de document :
Article dans une revue
Astronomy and Astrophysics - A&A, EDP Sciences, 2014, 569, 〈10.1051/0004-6361/201424756〉
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Contributeur : Marie-Paule Pomies <>
Soumis le : mardi 9 septembre 2014 - 08:56:15
Dernière modification le : vendredi 14 décembre 2018 - 01:25:23

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Holger S. P. Müller, Javier R. Goicoechea, José Cernicharo, M. Agúndez, Jérôme Pety, et al.. Revised spectroscopic parameters of SH$^+$ from ALMA and IRAM 30 m observations. Astronomy and Astrophysics - A&A, EDP Sciences, 2014, 569, 〈10.1051/0004-6361/201424756〉. 〈hal-01062001〉



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