Search for anions in molecular sources: C4H- detection in L1527

M. Agundez; J. Cernicharo; M. Guelin; M. Gerin; M. C. McCarthy; P. Thaddeus

doi:10.1051/0004-6361:20078985

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arXiv · 0712.1174

Search for anions in molecular sources: C4H- detection in L1527

M. Agundez·J. Cernicharo·M. Guelin·M. Gerin·M. C. McCarthy·P. Thaddeus

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Abstract

We present the results of a search for the negative ion C4H- in various dark clouds, low mass star-forming regions and photon-dominated regions (PDRs). We have also searched for C6H-, C2H- and CN- in some of the sources. The millimeter-wave observations were carried out with the IRAM-30m telescope. We detect C4H-, through the J = 9-8 and J = 10-9 rotational transitions, in the low mass star-forming region L1527. We thus confirm the tentative detection of the J = 9-8 line recently reported toward this source. The [C4H-]/[C4H] ratio found is 0.011 %, which is slightly lower than the value observed in IRC +10216, 0.024 %, but above the 3 sigma upper limit we derive in TMC-1, < 0.0052 %. We have also derived an upper limit for the [C6H-]/[C6H] ratio in the Horsehead Nebula, and for various anion-to-neutral ratios in the observed sources. These results are compared with recent chemical models.

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M. Agundez, J. Cernicharo, M. Guelin, M. Gerin, M. C. McCarthy, P. Thaddeus. 2008-01-18. Search for anions in molecular sources: C4H- detection in L1527. https://doi.org/10.1051/0004-6361%3A20078985

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