We present large scale 9'x 27'(25 pc x 70 pc) far-IR observations around Sgr
B2 using the Long-wavelength spectrometer (LWS) on board the Infrared Space
Observatory (ISO). The spectra are dominated by the strong continuum emission
of dust, the widespread molecular absorption of light hydrides (OH, CH and H2O)
and the fine structure lines of [NII], [NIII], [OIII], [CII] and [OI]. The
molecular richness in the outer layers of Sgr B2 is probed by the ISO-LWS
Fabry-Perot (35 km s^-1) detections towards Sgr B2(M), where more that 70 lines
from 15 molecular and atomic species are observed at high signal to noise
ratio.Comment: 46 pages, 10 figures, 5 tables, accepted in ApJ part I. (Figs. 1, 2,
  3, 9 and 10 have been bitmapped to low resolution

Cernicharo, J.

Goicoechea, J. R.

Rodriguez-Fernandez, N. J.

The Astrophysical Journal

English

arXiv

International audienceWe present large-scale 9'×27' (~25pc×70pc) far-IR observations around Sgr B2 using the Long-Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The spectra are dominated by the strong continuum emission of dust, the widespread molecular absorption of light hydrides (OH, CH, and H2O), and the fine-structure lines of [N II], [N III], [O III], [C II], and [O I]. The widespread dust emission is reproduced by a cold component (Td~=13-22 K) together with a warm component (Td~=24-38 K), representing ~40-100 K. PDR models can explain the enhanced column density of species such as H2O, OH, and O0. However, they fail to reproduce the observed NH3/NH2/NH~=100/10/1 abundance ratios. For N-bearing species, it seems that shock chemistry has to be invoked. The molecular richness in the outer layers of Sgr B2 is probed by the ISO/LWS Fabry-Pérot (~35 km s-1) detections toward Sgr B2(M), where more than 70 lines from 15 molecular and atomic species are observed at high signal-to-noise ratios

Goicoechea, Javier R.

Cernicharo, José

HAL-OBSPM

The Far-Infrared Spectrum of the Sagittarius B2 Region: Extended Molecular Absorption, Photodissociation, and Photoionization

HAL-INSU

Hal-Diderot

We present large scale 9'x 27'(25 pc x 70 pc) far-IR observations around Sgr B2 using the Long-wavelength spectrometer (LWS) on board the Infrared Space Observatory (ISO). The spectra are dominated by the strong continuum emission of dust, the widespread molecular absorption of light hydrides (OH, CH and H2O) and the fine structure lines of [NII], [NIII], [OIII], [CII] and [OI]. The molecular richness in the outer layers of Sgr B2 is probed by the ISO-LWS Fabry-Perot (35 km s^-1) detections towards Sgr B2(M), where more that 70 lines from 15 molecular and atomic species are observed at high signal to noise ratio.Peer reviewe

Rodríguez-Fernández, Nemesio J.

Digital.CSIC

The Far‐Infrared Spectrum of the Sagittarius B2 Region: Extended Molecular Absorption, Photodissociation, and Photoionization

Goicoechea, Javier

Rodriguez-Fernandez, Nemesio

Cernicharo, Jose