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Persistent URL http://purl.org/net/epubs/work/10867553
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Record Id 10867553
Title ISO-LWS Observations Of Gas And Dust In The Galactic Centre
Abstract The ISO-LWS observed Sagittarius A* over the wavelength range of 46-197 ?m. These previously unpublished spectra contain about 22 spectral lines in emission of atomic and ionic species (OI, OIII, CII, NII and NIII), as well as emission and absorption lines from molecular species (OH, CH, CO and o-H2O). ISO mapped the region in a 40 position, half-beam sampled grid, and used both the grating and Fabry-Perot modules. We have prepared spectral maps of most of the lines, but here discuss primarily the radiative transfer modelling of radiation within the central beam on Sgr A*. We used ISO-LWS spectra to constrain the physical conditions in Sgr A* by comparing the observed spectra with the emission and the absorption line intensities predicted via radiative transfer simulations. Preliminary results show that the spectral energy distribution of Sgr A* within the 80" ISO beam that includes the CND is due to thermal dust emission that can be fitted by the sum of an 85 K modified blackbody arising from a central cavity of r=1.2 pc in radius with a low column density of N(H2)=4.0x1021 cm2, and a 40.5 K modified blackbody curve and a higher column density, N(H2)= 3.0x1022 cm2. This simple model is able to reproduce most of the ionic lines, which are excited in the CND; the central cavity provides only a small contribution to the intensity of the spectral lines. The molecular lines, and in particular the OH absorption features, require substantive additional contributions from foreground absorption that is consistent with a visual extinction AV 30, the same value that is derived from other studies. http://adsabs.harvard.edu/abs/2011AAS...21732305E
Organisation STFC , RALSP
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Language English (EN)
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Journal Article American Astronomical Society Meeting Abstracts 217 43 (2011): 323.05. 2011