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Long-term spectral changes in the partial-covering candidate NLS1 1H 0707-495

L. C. Gallo·Y. Tanaka·Th. Boller·A. C. Fabian·S. Vaughan·W. N. Brandt
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Abstract

We compare two XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy 1H 0707-495 separated by two years, and discuss the results in terms of the partial-covering phenomenon. The second longer observation once again displays a sharp (< 200 eV) spectral drop above 7 keV; however, in contrast to the first observation, the edge depth and energy have changed significantly. In addition to changes in the edge parameters, the high-energy spectrum appears steeper. The changes in the high-energy continuum can be adequately explained in terms of a partial-covering absorber outflowing from the central region. The low-energy spectrum also shows significant long-term spectral variability, including: a substantial increase in the disc temperature; detection of a ~0.9 keV emission feature; and the presence of warm absorption that was also detected during the ASCA mission, but not seen during the first XMM-Newton observation. The large increase in disc temperature, and more modest rise in luminosity, can be understood if we consider the slim-disc model for 1H 0707-495. In addition, the higher disc luminosity could be the driving force behind the outflow scenario and the re-appearance of a warm medium during the second XMM-Newton observation.

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L. C. Gallo, Y. Tanaka, Th. Boller, A. C. Fabian, S. Vaughan, W. N. Brandt. 2004-08-10. Long-term spectral changes in the partial-covering candidate NLS1 1H 0707-495. https://doi.org/10.1111/j.1365-2966.2004.08248.x

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