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 microns, using the Herschel-SPIRE spectrometer. Nineteen
molecular lines originating from CO, 13CO, 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 x 10^4 cm-3,
CO column density N(CO) ~ 3.5 x 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 x 10^21 cm^-2. Astronomy & Astrophysics HERSCHEL special Issue, in
press.
