First detection of a THz water maser in NGC 7538-IRS1 with SOFIA and new 22 GHz e-MERLIN mapsF. Herpin, A. Baudry, A. M. S. Richards, M. D. Gray, N. Schneider, K. M. Menten, F. Wyrowski, S. Bontemps, R. Simon and H. WiesemeyerA&A, 606 (2017) A52DOI: https://doi.org/10.1051/0004-6361/201731056