Detection of polarized mm and sub - mm emission from Sgr A ⋆
نویسنده
چکیده
We report the detection of linear polarization from Sgr A⋆ at 750, 850, 1350 and 2000μm which confirms the contribution of synchrotron radiation. From the lack of polarization at longer wavelengths it appears to arise in the millimetre/sub-millimetre excess. There are large position angle changes between the millimetre and sub-millimetre results and these are discussed in terms of a polarized dust contribution in the submillimetre and various synchrotron models. In the model which best explains the data the synchrotron radiation from the excess is self-absorbed in the millimetre region and becomes optically thin in the sub-millimetre. This implies that the excess arises in an extremely compact source ∼ 2 Schwarzschild radii. Subject headings: Galaxy: centre–Synchrotron radiation–Sgr A⋆
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