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Linear and Circular Polarization from
Author(s) -
Bower G. C.
Publication year - 2003
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200385040
Subject(s) - physics , polarimetry , polarization (electrochemistry) , astrophysics , linear polarization , accretion (finance) , accretion disc , circular polarization , active galactic nucleus , outflow , astronomy , astrophysical jet , general relativity , galaxy , optics , classical mechanics , meteorology , scattering , microstrip , laser , chemistry
We describe recent results for Sgr A*, M81* and other low luminosity active galactic nuclei. We have conducted linear and circular polarimetry over a frequency range of 1.4 to 230 GHz and detected a variety of phenomena. The polarization properties of the studied sources are substantially different from higher powered AGN. In the case of Sgr A*, we are able to eliminate ADAFs and Bondi‐Hoyle flows as possible models based on mmλ polarimetry. The detection of linear polarization at 230 GHz with the BIMA array indicates that the accretion rate onto the black hole is <10 –7 M ⊙ y –1 consistent with jet and CDAF models. Our success with Sgr A* demonstrates that we can learn about the nature of accretion and outflow in these sources with unprecedented detail. Ultimately, we may develop probes of general relativity in the strong‐field limit through polarization imaging.