XMM–Newton study of the complex and variable spectrum of NGC 4051

摘要: We study the X-ray spectral variability of narrow line Seyfert 1 galaxy NGC 4051 as observed during two XMM-Newton observations. To gain insight on general behaviour, we first apply model-independent techniques such rms spectra and flux-flux plots. then perform time-resolved analysis by splitting observations into 68 (2 ks each). The data show evidence for a neutral constant-reflection component constant emission from photoionized gas, which are included in all models. nuclear can be modelled both terms 'standard model' [pivoting power-law plus blackbody (BB) soft excess] two-component one (power law ionized reflection accretion disc). Both models reproduce source cannot distinguished statistical ground. distinction has thus to made physical basis. standard model results indicate that excess does not follow BB (L oc T 4 ), despite variation luminosity about order magnitude. resulting temperature is consistent with being same value PG quasars. Moreover, although slope correlated flux, pivoting, hardest photon indices so flat (Γ ∼ 1.3-1.4) require rather unusual scenarios. Furthermore, very low flux states exhibit an inverted r-flux behaviour disagrees simple pivoting interpretation. These problems solved thermal, but due component. In this context, power (about 2.2) slope-flux correlation explained relative contribution components also explains shape plot relationship. inner disc closely follows predictions light-bending model, suggesting most primary produced innermost regions, only few gravitational radii (rg) central black hole.