PCA of PCA: Principal Component Analysis of Partial Covering Absorption in NGC 1365

Abstract

We analyse 400 ks of XMM-Newton data on the active galactic nucleus NGC 1365 using principal component analysis (PCA) to identify model independent spectral components. We find two significant components and demonstrate that they are qualitatively different from those found in MCG?6-30-15 using the same method. As the variability in NGC 1365 is known to be due to changes in the parameters of a partial covering neutral absorber, this shows that the same mechanism cannot be the driver of variability in MCG-6-30-15. By examining intervals where the spectrum shows relatively low absorption we separate the effects of intrinsic source variability, including signatures of relativistic reflection, from variations in the intervening absorption. We simulate the principal components produced by different physical variations, and show that PCA provides a clear distinction between absorption and reflection as the drivers of variability in AGN spectra. The simulations are shown to reproduce the PCA spectra of both NGC 1365 and MCG-6-30-15, and further demonstrate that the dominant cause of spectral variability in these two sources requires a qualitatively different mechanism.

arXiv comment8 pages, 10 figures. Accepted for publication in MNRAS

References in corpus (18)

• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• X-ray reflected spectra from accretion disk models. III. A complete grid of ionized reflection calculations
• A long hard look at MCG-6-30-15 with XMM-Newton
• A rapidly spinning supermassive black hole at the centre of NGC 1365
• Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei
• The lack of variability of the iron line in MCG-6-30-15: general relativistic effects
• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• An absorption origin for the X-ray spectral variability of MCG-6-30-15
• XMM-Newton study of the complex and variable spectrum of NGC 4051
• NuSTAR Spectroscopy of GRS 1915+105: Disk Reflection, Spin, and Connections to Jets
• Discovery of high-frequency iron K lags in Ark 564 and Mrk 335
• Negative X-ray reverberation time delays from MCG-6-30-15 and Mrk 766
• The variable X-ray spectrum of Markarian 766 - I. Principal components analysis
• Highly ionized iron absorption lines from outflowing gas in the X-ray spectrum of NGC 1365
• The nature of X-ray spectral variability in Seyfert Galaxies
• The variable OVIII Warm Absorber in MCG-6-30-15
• Imaging the Circumnuclear Region of NGC 1365 with Chandra
• Principal Component Analysis of MCG--6-30-15 with XMM-Newton

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• Revealing the ultra-fast outflow in IRAS 13224-3809 through spectral variability
• Revealing the X-ray Variability of AGN with Principal Component Analysis
• XMM-Newton Campaign On Ultraluminous X-ray Source NGC 1313 X-1: Wind vs. State Variability
• The Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR
• Using principal component analysis to understand the variability of PDS 456
• The X-ray variability of Seyfert 1.8/1.9 galaxies
• Multi-epoch X-ray spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 478
• Variable blurred reflection in the narrow-line Seyfert 1 galaxy Mrk 493
• X-ray Variability in the Symbiotic Binary RT Cru: Principal Component Analysis
• X-ray narrow emission lines from the nuclear region of NGC 1365
• Relativistic Reflection Modeling in AGN and Related Variability from PCA: A Brief Review
• Disentangling the X-ray variability in the Lyman continuum emitter Haro 11
• IGR J12580+0134: The Nearest Tidal Disruption Event and its Faint Resurrection