An Examination of the Spectral Variability in NGC 1365 with Suzaku

Abstract

We present jointly analyzed data from three deep Suzaku observations of NGC 1365. These high signal-to-noise spectra enable us to examine the nature of this variable, obscured AGN in unprecedented detail on timescales ranging from hours to years. We find that, in addition to the power-law continuum and absorption from ionized gas seen in most AGN, inner disk reflection and variable absorption from neutral gas within the Broad Emission Line Region are both necessary components in all three observations. We confirm the clumpy nature of the cold absorbing gas, though we note that occultations of the inner disk and corona are much more pronounced in the high-flux state (2008) than in the low-flux state (2010) of the source. The onset and duration of the "dips" in the X-ray light curve in 2010 are both significantly longer than in 2008, however, indicating that either the distance to the gas from the black hole is larger, or that the nature of the gas has changed between epochs. We also note significant variations in the power-law flux over timescales similar to the cold absorber, both within and between the three observations. The warm absorber does not vary significantly within observations, but does show variations in column density of a factor of more than 10 on timescales less than 2 weeks that seem unrelated to the changes in the continuum, reflection or cold absorber. By assuming a uniform iron abundance for the reflection and absorption, we have also established that an iron abundance of roughly 3.5 times the solar value is sufficient to model the broad-band spectrum without invoking an additional partial-covering absorber. Such a measurement is consistent with previous published constraints from the 2008 Suzaku observation alone, and with results from other Seyfert AGN in the literature.

19 pages, 11 figures, accepted for publication in MNRAS

References in corpus (7)

• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• Constraining Black Hole Spin Via X-ray Spectroscopy
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• Broad iron K-alpha emission lines as a diagnostic of black hole spin
• The XMM-Newton long look of NGC 1365: uncovering of the obscured X-ray source
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Cited by in corpus (33)

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• Astrophysical Black Holes: A Compact Pedagogical Review
• MAGNUM survey: A MUSE-Chandra resolved view on ionized outflows and photoionization in the Seyfert galaxy NGC 1365
• NuSTAR and XMM-Newton Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk
• Testing the no-hair theorem with the continuum-fitting and the iron line methods: a short review
• Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the Narrow Line Seyfert 1 galaxy SWIFT J2127.4+5654
• Iron K and Compton hump reverberation in SWIFT J2127.4+5654 and NGC 1365 revealed by NuSTAR and XMM-Newton
• X-ray absorption, nuclear infrared emission and dust covering factors of AGN: testing Unification Schemes
• The Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR
• A Suzaku, NuSTAR, and XMM-Newton view on variable absorption and relativistic reflection in NGC 4151
• NGC 1365: A low column density state unveiling a low ionization disk wind
• Measuring the Coronal Properties of IC4329A with NuSTAR
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• Impact of the returning radiation on the analysis of the reflection spectra of black holes
• Long Term Wind-Driven X-Ray Spectral Variability of NGC 1365 with Swift
• Modelling the X-ray polarimetric signatures of complex geometry: the case study of the "changing look" AGN NGC 1365
• Near-infrared observations of star formation and gas flows in the NUGA galaxy NGC 1365
• Quasi Normal Modes of hairy black holes at higher--order WKB approach
• The soft X-ray spectrum of the luminous narrow line Seyfert galaxy PG1211+143 - evidence for a second high velocity outflow component
• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
• The X-ray variability of Seyfert 1.8/1.9 galaxies
• BAT AGN Spectroscopic Survey-XXIII. A New Mid-Infrared Diagnostic for Absorption in Active Galactic Nuclei
• The Chandra/HETG view of NGC 1365 in a Compton-thick state
• Variable mass accretion and failed wind explain changing look phenomena in NGC 1365
• Accreting Black Holes
• Searching for Super-Eddington Quasars using a Photon Trapping Accretion Disc Model
• Constraints on the radio loud/radio quiet dichotomy from the fundamental plane
• An X-ray high-frequency quasi-periodic oscillation in NGC 1365
• X-ray narrow emission lines from the nuclear region of NGC 1365
• San Pedro Martir observations of microvariability in obscured quasars