Beppo SAX X-Ray Observations of PKS 1934-63 and S5 1946+708
Abstract
X-ray observations of PKS1934-63 and S5 1946+708 have been made with Beppo SAX lasting 100 and 40ksec, respectively. Both sources were detected, and in both there is evidence (at 90% confidence) of a strong iron Kα line which would indicate that the nuclei are surrounded by Compton thick material (~1gcm-2). For 1946+708 VLBI HI absorption data are available from the literature. With the condition that free-free absorption should be modest for the source to be observable a minimum radius of around 20pc is derived for the absorbing torus. The torus is predominantly molecular with a density of 108cm-3. The corresponding pressure is rather high. Observations with XMM have been requested to verify the large equivalent width of Kα with a better confidence level. In 1934-63 no important HI absorption was previously detected and no nucleus has been seen in radio data at 8GHz. If this is due to free-free absorption a molecular torus with a radius less than 5pc could be responsible. The density would be 108cm-3 or more. The relatively low S/N ratio of our observations does not allow a fully convincing conclusion to be reached. But our discussion shows that the combination of X-ray and high resolution 21-cm absorption data can provide important information on the physical parameters in the absorbing `torus'. Paper to appear in full in Astronomy and Astrophysics.
- Publication:
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Publications of the Astronomical Society of Australia
- Pub Date:
- 2003
- DOI:
- Bibcode:
- 2003PASA...20..156W