After reported unsuccessful searches for the 1_1,0 – 1_1,1 transition of thioformaldehyde, H₂CS, at 1046.5 MHz, the next higher 2_1,1 – 2_1,2 transition at 3139.4 MHz was detected with the Parkes 64 m radio telescope in absorption toward the Galactic hot core source Sgr B2 by
M. W. Sinclair, N. Fourikis, J. C. Ribes, B. J. Robinson, R. D. Brown, and P. D. Godfrey,
Detection of Interstellar Thioformaldehyde
Aust. J. Phys. 26, 85–91 (1973).

Soon thereafter, the 4_1,3 – 4_1,4 transition was observed with the ARO 46 m telescope by
L. H. Doherty, J. M. MacLeod, and T. Oka,
Detection of the 10.464 GHz Transition of Interstellar Thioformaldehyde
Astrophys. J. 192, L157–L160 (1974).
The line was also seen in absorption toward Sgr B2. The excitation conditions seem to be non-thermal, similar to those of of formaldehyde, H₂CO.
The first two authors also report the detection of the J = 3 transition in
BAAS 7, 265 (1975).

The first R-branch transition, 3_1,2 – 2_1,1 near 104.617 GHz was detected in emission toward several hot core sources with the NRAO 11 m telecope by
H. S. Liszt,
Upper limits on the abundance of the sulfur dimer in molecular clouds
Astrophys. J. 146, 303–306 (1978).

The 3_1,3 – 2_1,2 transition near 101.478 GHz was also detected toward the cold dense molecular clouds TMC-1 and L134N with the NRAO 43 m telescope by
W. M. Irvine, P. Friberg, N. Kaifu, K. Kawaguchi, Y. Kitamura, H. E. Matthews, Y. Minh, S. Saito, N. Ukita, S. Yamamoto,
Observations of some oxygen-containing and sulfur-containing organic molecules in cold dark clouds
Astrophys. J. 342, 871–875 (1989).

Quite recently, H₂CS was among several molecules detected with the IRAM 30 m telecope in the circumstellar envelope of the carbon-rich AGB star CW Leo, aka IRC +10216:
M. Agúndez, J. P. Fonfría Expósito, J. Cernicharo, J. R. Pardo and M. Guélin,
Detection of Circumstellar CH₂CHCN, CH₂CN, CH₃CCH, and H₂CS
Astron. Astrophys. 479, 493–501 (2008).

The 3_1,3 – 2_1,2 transition of H₂C³⁴S near 99.774 GHz was observed in emission toward Orion KL with the OSO 20 m telescopy by
F. F. Gardner, B. Höglund, C. Shurke, A. Stark, and T. L. Wilson,
Observations of //ortho//- and //para//-thioformaldehyde
Astron. Astrophys. 219, 454–457 (1985).

H₂¹³CS was first detected by
S. E. Cummins, R. A. Linke, and P. Thaddeus,
A survey of the millimeter-wave spectrum of Sagittarius B2
Astrophys. J. 576, 819–878 (1986).

The 1_0,1 – 0_0,0 and 3_0,3 – 2_0,2 transitions of HDCS near 31.002 and 92.982 GHz were identified in the course of a Nobeyama 45 m line survey of TMC-1 by
H. Minowa, M. Satake, T. Hirota, S. Yamamoto, M. Ohishi, and N. Kaifu,
Laboratory Microwave Spectroscopy of HDCS and Its Astronomical Detection toward TMC-1
Astrophys. J. 491, L63–L66 (1997).

Even D₂CS has been observed with the IRAM 30 m telescopy by
N. Marcelino, J. Cernicharo, E. Roueff, M. Gerin, and R. Mauersberger,
Deuterated Thioformaldehyde in the Barnard 1 Cloud
Astrophys. J. 620, 308–320 (2005).

Contributor(s): H. S. P. Müller; 07, 2011