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Searches for interstellar imidazole and cyanoform

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Abstract

The reported observations were made in March 1979 with the 20 m millimeter-wave telescope of the Onsala Space Observatory. Observations were performed by position switching in the total power mode, azimuth offsets typically being one degree. The sources observed include dark and molecular clouds, and the carbon star IRC+10216. The observational data are presented in a table. No lines were detected to the indicated limits regarding the peak-to-peak antenna temperature. The negative results regarding the observed cyanoform band provide limits on peak-to-peak antenna temperature also for HCOOH.

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... The structures of these molecules are simple enough that it is possible to search for them via their rotational transitions. However, searches to date have yielded only negative results [pyrrole: Kutner et al. (1980), furan: Dickens et al. (2001), imidazole: Irvine et al. (1981), pyrimidine: Charnley et al. (2005)]. ...
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Recent observational and experimental evidence for the presence of complex organics in space is reviewed. Remote astronomical observations have detected \(\sim \)200 gas-phased molecules through their rotational and vibrational transitions. Many classes of organic molecules are represented in this list, including some precursors to biological molecules. A number of unidentified spectral phenomena observed in the interstellar medium are likely to have originated from complex organics. The observations of these features in distant galaxies suggests that organic synthesis had already taken place during the early epochs of the Universe. In the Solar System, almost all biologically relevant molecules can be found in the soluble component of carbonaceous meteorites. Complex organics of mixed aromatic and aliphatic structures are present in the insoluble component of meteorites. Hydrocarbons cover much of the surface of the planetary satellite Titan and complex organics are found in comets and interplanetary dust particles. The possibility that the early Solar System, or even the early Earth, have been enriched by interstellar organics is discussed.
... Observation of pyrimidine and imidazole in the interstellar medium (ISM) by radioastronomy has been attempted but has not been successful so far. Upper limits of abundance have been established for pyrimidine [88] and imidazole [89]. More recently, a particular interstellar spectral feature, previously observed in hot molecular cores towards W51 e1/e2 [88], is considered as being possibly due to pyrimidine, and has been re-analyzed favorably [90], but this is insufficient to confirm the pyrimidine assignment without justification via other lines, possibly due to pyrimidine, which require further observation and study. ...
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