SIMBAD references

Forty-eight candidate massive protostar regions were surveyed for methyl cyanide (CH₃CN) emission using the Heinrich Hertz Telescope (HHT) on Mount Graham, AZ. CH₃CN J=12-11 emission at 220 GHz was detected toward 25 regions. Thirteen of these are new detections, yielding a substantial number of new candidates for massive protostars. The CH₃¹³CN (J=12-11) isotopomer was included in the bandpass of all observed sources and was detected toward eight sources in our sample. These sources are probably optically thick in some of the CH₃CN lines. CH₃CN J=25-24 emission at 460 GHz was detected in at least one K-component toward five of 11 sources observed in this transition. Using a rotational equilibrium temperature analysis we estimate the CH₃CN rotation temperatures and beam-averaged column densities for 20 of the sources.