We present far infrared spectra, obtained with the Long Wavelength Spectrometer (LWS) onboard the ISO satellite, on the B335 dark cloud region. In particular, deep integration spectra were acquired on the far infrared outflow exciting source, located in the B335 core, and on the three associated Herbig Haro (HH) objects HH119 A, B and C. In addition, we mapped a region of about 12' in RA and 5' in DEC covering the whole molecular outflow.
A [CII] 157μm emission uniformely distributed in all the region is observed, with the intensity expected for a photodissociation region excited by the average interstellar field. The [OI]63μm emission is detected only from the HH objects and from the B335 FIR source; the observed line intensity is in agreement with the existing shock models. CO line emission from the rotation level J=15 to J=18 are detected in B335 FIR only: we model this emission as due to a compact (7x10-3 pc), warm (T=150 K) and dense (nH2 = 4x106 cm-3) region. We think that such a warm gas connot be excited in the collapsing envelope as modelled for this source. Finally, we find that the thermal emission of the FIR source could be fitted by a model assuming a free-fall density distribution law ρ α r-1.5, although a flatter density profile (r-0.5 produces a much better fit with the LWS spectrum shortward of 60μm
