Melosso, M.M.MelossoMelli, A.A.MelliPuzzarini, C.C.PuzzariniCODELLA, CLAUDIOCLAUDIOCODELLASpada, L.L.SpadaDore, L.L.DoreLefloch, B.B.LeflochBachiller, R.R.BachillerCeccarelli, C.C.CeccarelliCernicharo, J.J.CernicharoBarone, V.V.Barone2020-11-162020-11-1620180004-6361http://hdl.handle.net/20.500.12386/28367Context. C-cyanomethanimine (HNCHCN), existing in the two Z and E isomeric forms, is a key prebiotic molecule, but, so far, only the E isomer has been detected toward the massive star-forming region Sagittarius B2(N) using transitions in the radio wavelength domain. <BR /> Aims: With the aim of detecting HNCHCN in Sun-like-star forming regions, the laboratory investigation of its rotational spectrum has been extended to the millimeter-/submillimeter-wave (mm-/submm-) spectral window in which several unbiased spectral surveys have been already carried out. <BR /> Methods: High-resolution laboratory measurements of the rotational spectrum of C-cyanomethanimine were carried out in the 100-420 GHz range using a frequency-modulation absorption spectrometer. We then searched for the C-cyanomethanimine spectral features in the mm-wave range using the high-sensitivity and unbiased spectral surveys obtained with the IRAM 30-m antenna in the ASAI context, the earliest stages of star formation from starless to evolved Class I objects being sampled. <BR /> Results: For both the Z and E isomers, the spectroscopic work has led to an improved and extended knowledge of the spectroscopic parameters, thus providing accurate predictions of the rotational signatures up to 700 GHz. So far, no C-cyanomethanimine emission has been detected toward the ASAI targets, and upper limits of the column density of 10<SUP>11</SUP>-10<SUP>12</SUP> cm<SUP>-2</SUP> could only be derived. Consequently, the C-cyanomethanimine abundances have to be less than a few 10<SUP>-10</SUP> for starless and hot-corinos. A less stringent constraint, ≤10<SUP>-9</SUP>, is obtained for shocks sites. <BR /> Conclusions: The combination of the upper limits of the abundances of C-cyanomethanimine together with accurate laboratory frequencies up to 700 GHz poses the basis for future higher sensitivity searches around Sun-like-star forming regions. For compact (typically less than 1″) and chemically enriched sources such as hot-corinos, the use of interferometers as NOEMA and ALMA in their extended configurations are clearly needed. <P />The complete list of the measured transitions for Z- and E-C-cyanomethanimine is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A121">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A121STAMPAenArticle10.1051/0004-6361/2017319722-s2.0-85041394344000429204300001https://www.aanda.org/articles/aa/abs/2018/01/aa31972-17/aa31972-17.html2018A&A...609A.121MFIS/05 - ASTRONOMIA E ASTROFISICA