1. Orion-KL EVLA spectrum Karl Menten, Dec. 24, 2010 Received spectrum from R. Perley on Dec. 23, 2010 Frequency range 23654.50–24654.37 MHz Subtracted 2.2586 MHz to frequencies so that NH 3 lines are centered at their rest frequencies. Scale was fixed by assuming an LSR velocity of ≈ +8 km/s (for the (J,K) = (1,1), (2,2),and (3,3) lines (Barrett et al. 1977, ApJ 211, L39) (Barrett et al. 1977, ApJ 211, L39) Comment: Data appear to be of very high quality. There are a few single channel spikes of intensity a few sigma increased noise level at frequencies higher than 24.5 GHz

2. Line content of spectrum Detect total of 13 “strong”(insh) lines 11 previously detected in ISM, listed on Lovas’ website: http://physics.nist.gov/PhysRefData/Micro/Html/contents.html Dominated by lines from ammonia (NH 3 ) 5 lowest meta-stable inversion transitions (J,K) = (1,1), (2,2), (3,3), (4,4), and (5,5) non-meta-stable (9,8) and (10,9) lines (6,6) line from 15 NH 3 isotopologue, [ 14 N/ 15 N]≈250 2(0,2)-1(0,1) E/A doublet of methyl formate CH3CHO OCS 2-1 2 Unidentified lines There certainly are (unidentified, but possiby identifiable) weaker lines in the spectrum

3. Line rest frequencies 23657.471 ( 5) NH3 9(8)-9(8) 23693.9051( 1) NH3 1(1)-1(1) F,F1=3/2,1-5/2,2 23694.4700( 1) NH3 1(1)-1(1) F,F1=1/2,1-3/2,1 23694.5060( 1) NH3 1(1)-1(1) F,F1=5/2,2-5/2,2 23695.0672( 1) NH3 1(1)-1(1) F,F1=3/2,2-3/2,1 23696.0297( 2) NH3 1(1)-1(1) F,F1=1/2,0-1/2,1 23720.575 ( 5) NH3 2(2)-2(2) F1=1-2 23721.336 ( 5) NH3 2(2)-2(2) F1=3-2 23722.6336( 1) NH3 2(2)-2(2) F1=3-3 23723.929 ( 5) NH3 2(2)-2(2) F1=2-3 23724.691 ( 5) NH3 2(2)-2(2) F1=2-1 23867.805 ( 5) NH3 3(3)-3(3) F1=2-3 23868.450 ( 5) NH3 3(3)-3(3) F1=4-3 23870.1296( 1) NH3 3(3)-3(3) F1=4-4 23871.807 ( 5) NH3 3(3)-3(3) F1=3-4 23872.453 ( 5) NH3 3(3)-3(3) F1=3-2 23922.3132( 2) 15NH3 6(6)-6(6) 24039.8 Unidentified 24083.4 Unidentified 24139.4169( 1) NH3 4(4)-4(4) 24205.287 ( 5) NH3 10(9)-10(9) 24296.491*( 8) CH3OCHO 2(0,2)-1(0,1) E 24298.481*( 8) CH3OCHO 2(0,2)-1(0,1) A 24325.927 ( 1) OCS 2-1 24532.9887( 1) NH3 5(5)-5(5) Meta-stable NH3 lines have 5 main groups of hyperfine structure components which are blended in Orion-KL spectrum