Another Interpretation of the Disk-Line Profile for the Seyfert 1 Galaxy MCG-6-30-15
Abstract
The Seyfert 1 galaxy MCG-6-30-15 is a representative object possessing a ``disk-line'' (a broad and skewed feature around 5-7keV in an X-ray spectrum). Using the longest MCG-6-30-15 observation with ASCA, Matsumoto et al. (2003, PASJ, 55, 615) found an interesting time-variability: the RMS variability as a function of a time-bin-width decreases more rapidly in the disk-line energy band (5.0-6.6keV) than those in the other energy bands, as the time-bin-width increases from ∼ 104s, to ∼ 105s. In this paper, we argue that this energy-dependent change in the RMS variability as a function of the time-bin-width is difficult to be reproduced by simply considering the variability of a ``disk-line'', but that the RMS variability of the continuum component should have an energy-dependent evolution associated with the time-bin-width change. Such an energy-dependent variability of the continuum component can be realized by introducing absorption components with the typical variation time scale longer than that of the continuum. In this interpretation, a significant part of the broad excess feature in 5-7keV is considered to be the result of a transparent spectral window of the warm absorbers.
- Publication:
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Publications of the Astronomical Society of Japan
- Pub Date:
- June 2003
- DOI:
- 10.1093/pasj/55.3.625
- Bibcode:
- 2003PASJ...55..625I
- Keywords:
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- galaxies: individual (MCG-6-30-15);
- galaxies: Seyfert;
- X-rays: galaxies