Publication Date:
2019-07-13
Description:
The variable warm absorber seen with ASCA in the X-ray spectrum of MCG 6-30-15 shows complex time behaviour in which the optical depth of O VIII anticorrelates with the flux whereas that of O VII is unchanging. The explanation in terms of a two zone absorber has since been challenged by BeppoSAX observations. These present a more complicated behaviour for the O VII edge. The explanation we offer for both ASCA and BeppoSAX observations requires a very simple photoionization model together with the presence of a third, intermediate, zone and a period of very low luminosity. In practice warm absorbers are likely to be extended, multi-zone regions of which only part causes directly observable absorption edges at any given time depending on the value of the luminosity.
Keywords:
Astrophysics
Type:
Astrophysical Plasmas: Codes, Models, and Observations; 9; 334-335
Format:
text
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