Limits on chemical complexity in diffuse clouds: search for CH3OH and HC5N absorption - Astrophysics > Astrophysics of GalaxiesReport as inadecuate




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Abstract: Context: An unexpectedly complex polyatomic chemistry exists in diffuseclouds, allowing detection of species such as C2H, C3H2, H2CO and NH3 whichhave relative abundances that are strikingly similar to those inferred towardthe dark cloud TMC-1Aims: We probe the limits of complexity of diffuse cloud polyatomicchemistry.Methods: We used the IRAM Plateau de Bure Interferometer to search forgalactic absorption from low-lying J=2-1 rotational transitions of A- andE-CH3OH near 96.740 GHz and used the VLA to search for the J=8-7 transition ofHC5N at 21.3 GHz.Results: Neither CH3OH nor HC5N were detected at column densities well belowthose of all polyatomics known in diffuse clouds and somewhat below the levelsexpected from comparison with TMC-1. The HCN-HC5N ratio is at least 3-10 timeshigher in diffuse gas than toward TMC-1.Conclusions: It is possible to go to the well once or more too often



Author: H. S. Liszt, J. Pety, R. Lucas

Source: https://arxiv.org/







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