An analysis of infrared emission spectra from the regions near the Galactic Centre |
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| Authors: | Marcella Contini |
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| Institution: | School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel |
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| Abstract: | We present consistent modelling of line and continuum infrared (IR) spectra in the region close to the Galactic Centre. The models account for the coupled effect of shocks and photoionization from an external source. The results show that the shock velocities range between ∼65 and 80 km s−1 and the pre-shock densities between 1 cm−3 in the interstellar medium (ISM) to 200 cm−3 in the filamentary structures. The pre-shock magnetic field increases from 5 × 10−6 G in the surrounding ISM to ∼8 × 10−5 G in the arched filaments. The stellar temperatures are ∼38 000 K in the Quintuplet cluster and ∼27 000 K in the Arches Cluster. The ionization parameter is relatively low (<0.01) with the highest values near the clusters, reaching a maximum >0.01 near the Arches Cluster. Depletion from the gaseous phase of Si is found throughout the whole observed region, indicating the presence of silicate dust. Grains including iron are concentrated throughout the arched filaments. The modelling of the continuum spectral energy distribution in the IR range indicates that a component of dust at temperatures of ∼100–200 K is present in the central region of the Galaxy. Radio emission appears to be thermal bremsstrahlung in the E2–W1 filaments crossing strip; however, a synchrotron component is not excluded. More data are necessary to resolve these questions. |
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| Keywords: | radiation mechanisms: general shockwaves ISM: abundances Galaxy: centre |
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