Broad-Band Temporal and Spectral Variation of 36 Active Galactic Nuclei Observed with Suzaku

Abstract

36 AGN data observed by Suzaku were compiled to examine the temporal variability in different energy bands covered by soft X-ray imaging systems (XRT + XIS: 0.5-10 keV) and Hard X-ray Detector (HXD: 15-50 keV) aboard Suzaku. Three band light curves were obtained in L (0.5-2 keV), M (2-10 keV), and H (15-50 keV) with a time binning of 5760 s. The L-band flux change was almost proportional to that of the M-band without offsets in most of type-1 AGNs. The slope (= dL/dM) of the correlation changed by more than a factor of 10 from Seyfert 2 to narrow-line Seyfert 1 galaxies (NLS1). The power-law component can explain the slope of Seyfert 1 galaxies with a typical index, Γ, of 1.9. For NLS1s with steeper slopes, an additional soft excess component is needed, whose variation should be proportional to that of the power-law component. It gives a new constraint to models for the soft excess component. The H-band flux change is a linear function of the M-band flux with a significant offset in the H-band. The slope can be explained by the power-law component with an absorption column from 10^22-24 cm^-2. The offset can be attributed to the reflection component, which is stable on a time scale of days.