Herschel-SPIRE spectroscopy of the DR21 molecular cloud core

We present far-infrared spectra and maps of the DR21 molecular cloud core between 196 and 671 μm, using the Herschel-SPIRE spectrometer. Nineteen molecular lines originating from CO, 13 CO, HCO + and H2O, plus lines of [N ii] and [CI] were recorded, including several transitions not previously detected. The CO lines are excited in warm gas with Tkin ∼ 125 K and nH2 ∼ 7 × 10 4 cm −3 , CO column density N(CO) ∼ 3.5 × 10 18 cm −2 and a filling factor of ∼12%, and appear to trace gas associated with an outflow. The rotational temperature analysis incorporating observations from ground-based telescopes reveals an additional lower excitation CO compoment which has a temperature ∼78 K and N(CO) ∼ 4.5×10 21 cm −2 .