===== Detection of Ammonia in the ISM ===== NH3 was observed first in its lowest //J// = //K// = 1 tunneling transition toward Sagittarius B2 (Sgr B2):\\ A. C. Cheung, D. M. Rank, C. H. Townes, D. D. Thornton, and W. J. Welch,\\ **[[https://doi.org/10.1103/PhysRevLett.21.1701|Detection of NH3 Molecules in the Interstellar Medium by Their Microwave Emission]]**\\ //Phys. Rev. Lett.// **21**, 1701–1705 (1968).\\ \\ The first detection of a rotation-inversion transition of NH3 was also reported: J. Keene, G. A. Blake, and T. G. Philips,\\ **[[https://ui.adsabs.harvard.edu/abs/1983ApJ...271L..27K|First Detection of the Ground-State //JK// = 10 – 00 Submillimeter Transition of Interstellar Ammonia]]**\\ //Astrophys. J.// **271**, L27–L30 (1983).\\ \\ T. L. Wilson, K. Ruf, C. M. Walmsley, R. N. Martin, T. A. Pauls, and W. Batria\\ reported on the\\ **[[https://ui.adsabs.harvard.edu/abs/1982A%26A...115..185W|Detection of the (8,8) and (9,9) Absorption Lines of Ammonia: the Hot Molecular Cloud toward Sgr B2]]**\\ //Astron. Astrophys.// **115**, 185−189 (1982).\\ Observations were made with the MPIfR 100 m Effelsberg telescope pointing toward Sgr B2(S).\\ \\ T. L. Wilson, C. Henkel, and S. Hüttemeister, G. Dahmen, A. Linhart, C. Lemme, and J. Schmidt-Burgk\\ reported on\\ **[[https://ui.adsabs.harvard.edu/abs/1993A%26A...276L..29W|Hot Ammonia Emission: Kinetic Temperature Gradients in Orion-KL]]**\\ //Astron. Astrophys.// **276**, L29−L32 (1993).\\ The MPIfR 100 m Effelsberg telescope was employed for observations of ammonia inversion transitions with 10 ≤ //J// = //K// ≤ 14.\\ \\ T. L. Wilson, C. Henkel, and S. Hüttemeister\\ announced\\ **[[https://doi.org/10.1051/0004-6361:20065591|The detection of the (J, K) = (18, 18) line of NH3]]**\\ //Astron. Astrophys.// **460**, 533–538 (2006).\\ Observations with the Effelsberg 100 m dish were successful toward Sgr B2(M) and Sgr B2(N); only an upper limit was reported for Orion KL.\\ \\ The detection of vibrationally excited NH3 (//v//2 = 1) was reported in:\\ R. Mauersberger, C. Henkel, and T. L. Wilson,\\ **[[https://ui.adsabs.harvard.edu/abs/1988A%26A...205..235M|Vibrationally Excited Ammonia toward Orion-KL]]**\\ //Astron. Astrophys.// **205**, 235–242 (1988).\\ The IRAM 30 m dish was used for observations near 140.1 GHz. --- NH2D was detected initially toward Sgr B2 and Orion KL:\\ B. E. Turner, B. Zuckerman, M. Morris, and P.Palmer,\\ **[[https://ui.adsabs.harvard.edu/abs/1978ApJ...219L..43T|Microwave Detection of Interstellar Deuterated Ammonia]]**\\ //Astrophys. J.// **219**, L43–L47 (1978).\\ E. N. Rodriguez Kuiper, B. Zuckerman, and T. B. H. Kuiper,\\ **[[https://ui.adsabs.harvard.edu/abs/1978ApJ...219L..49R|Deuterated Ammonia Toward the Orion Nebula]]**\\ //Astrophys. J.// **219**, L49–L53 (1978).\\ \\ 15NH3 was observed toward the Orion Molecular Cloud (OMC-1) soon thereafter:\\ T. L. Wilson and T. Pauls,\\ **[[https://ui.adsabs.harvard.edu/abs/1979A%26A....73L..10W|The Detection of Interstellar 15NH3]]**\\ //Astron. Astrophys.// **73**, L10–L12 (1979).\\ \\ NHD2 was detected first toward the L134N dark cloud which is also known as L183:\\ E. Roueff, S. Tiné, L. H. Coudert, G. Pineau des Forêts, E. Falgarone, and M. Gerin,\\ **[[https://ui.adsabs.harvard.edu/abs/2000A%26A...354L..63R|Detection of Doubly Deuterated Ammonia in L134N]]**\\ //Astron. Astrophys.// **354**, L63–L66 (2000).\\ \\ Finally, even ND3 was detected in NGC 1333 and in the Barnard 1 Cloud:\\ F. F. S. van der Tak, P. Schilke, H. S. P. Müller, D. C. Lis, T. G. Phillips, M. Gerin, and E. Roueff,\\ **[[https://doi.org/10.1051/0004-6361:20020647|Triply Deuterated Ammonia in NGC 1333]]**\\ //Astron. Astrophys.// **388**, L53–L56 (2002).\\ D. C. Lis, E. Roueff, M. Gerin, T. G. Phillips, L. H. Coudert, F. F. S. van der Tak, and P. Schilke,\\ **[[https://doi.org/10.1086/341132|Detection of Triply Deuterated Ammonia in the Barnard 1 Cloud]]**\\ //Astrophys. J.// **571**, L55–L58 (2002).\\ \\ The observation of 111 (0+) – 101 (0–) //ortho// transition of 15NH2D with the IRAM 30m telescope toward Barnard-1b, NGC1333-DCO+, and L1689N was reported by:\\ M. Gerin, N. Marcelino, N. Biver, E. Roueff, L. H. Coudert, M. Elkeurti, D. C. Lis, and D. Bockelée-Morvan,\\ **[[https://doi.org/10.1051/0004-6361/200911759|Detection of 15NH2D in dense cores: a new tool for measuring the 14N/15N ratio in the cold ISM]]**\\ //Astron. Astrophys.// **498**, L9–L12 (2009).\\ \\ ---- Contributor(s): H. S. P. Müller; 12, 2004; 06, 2006 & 01, 2010 ----