R. Mauersberger, C. Henkel, and L. J. Sage,
Dense gas in nearby galaxies. III – HC₃N as an extragalactic density probe,
Astron. Astrophys. 236, 63–68 (1990).

Source(s): NGC 253
Facility: IRAM 30 m

Comments:
Six transitions were observed between 81.8 and 236.6 GHz with quantum numbers J“ = 8, 9, 11, 14, 15, and 25.
A tentative detection of the J = 10 – 9 transition toward IC342 or M82 with the IRAM 30 m telescope had been reported previously:
C. Henkel, R. Mauersberger, and P. Schilke,
Molecules in external galaxies – The detection of CN, C₂H, and HNC, and the tentative detection of HC₃N,
Astron. Astrophys. 201, L23–L26 (1988).

F. Costagliola and S. Aalto,
Vibrationally Excited HC₃N in NGC 4418,
Astron. Astrophys. 515, Art. No. A71 (2010).

Source(s): NGC 4418
Facility: IRAM 30 m; JCMT

Comments:
This seems to be the first report on the detection of a vibrationally excited molecule in an Extragalactic source. The J” = 9, 15, 16, 24, 27, 29, and 37 between 90.9 and 345.6 GHz were observed for the ground vibrational state; six of the eight components of v₇ = 1, J“ = 9, 16, 24, and 27 and one component of v₆ = 1, J” = 24 were detected as well.

Contributor(s): S. Thorwirth; 09/2005; H. S. P. Müller, 07, 2010