Detection of [O I] 63µm in absorption toward SGR B2.
Prusti, T.; Liseau, R.; Burgdorf, M.; White, G.; Serra, G.; Caux, E.; Cernicharo, J.; Cox, P.; Molinari, S.; Lim, T.; Sidher, S.; Nisini, B.; Texier, D.; Saraceno, P.; Clegg, P. E.; Armand, C.; Furniss, I.; Gry, C.; Trams, N.; Baluteau, J. -P.; Swinyard, B.; Emery, R. J.; Joubert, M.; Pequignot, D.; Price, M.; Kessler, M.; Barlow, M.; Glencross, W.; Digiorgio, A.
Abstract
A high signal-to-noise 52-90μm spectrum is presented for the central part of the Sagittarius B2 complex. The data were obtained with the Long Wavelength Spectrometer on board the Infrared Space Observatory (ISO). The [O I] 63μm line is detected in absorption even at the grating spectral resolution of 0.29μm. A lower limit for the column density of atomic oxygen of the order of 10^19^cm^-2^ is derived. This implies that more than 40% of the interstellar oxygen must be in atomic form along the line of sight toward the Sgr B2 molecular cloud.