Methylamine vt=1

We used the imaging spectral line survey ReMoCA performed with the Atacama Large Millimeter/submillimeter Array (ALMA) to search for rotational transitions of methylamine in its first torsionally excited state toward the high-mass star forming region Sgr B2(N). The observed spectra are modeled under the assumption of local thermodynamic equilibrium (LTE). Accurate spectral predictions were obtained for the ground and first excited states of CH_3_NH_2_.

We report the first interstellar detection of methylamine in the vt=1 state toward the offset position Sgr B2(N1S) in the hot molecular core Sgr B2(N1). The LTE parameters derived previously from the rotational emission of methylamine in its torsional ground state toward Sgr B2(N1S) yield synthetic spectra of methylamine in the vt=1 state that are fully consistent with the ALMA spectra and allow us to identify five rotational lines of this state.