A multi-epoch X-ray study of the nearby Seyfert 2 galaxy NGC 7479: Linking column density variability to the torus geometry

Abstract

Active galactic nuclei (AGN) are powered by accreting supermassive black holes, surrounded by a torus of obscuring material. Recent studies have shown how the torus structure, formerly thought to be homogeneous, appears to be 'patchy': the detection of variability in the line-of-sight hydrogen column density, in fact, matches the description of an obscurer with a complex structure made of clouds with different column density. In this work, we perform a multi-epoch analysis of the X-ray spectra of the Seyfert 2 galaxy NGC 7479 in order to estimate its torus properties, such as the average column density and the covering factor. The measurement of the line-of-sight hydrogen column density variability of the torus allows us to obtain an upper limit on the cloud distance from the central engine. In addition, using the X-ray luminosity of the source, we estimate the Eddington ratio to be in a range of Edd=0.04-0.05 over all epochs.

Re-submitted to ApJ after minor reviews

References in corpus (11)

• The 1% Concordance Hubble Constant
• On the X-ray, optical emission line and black hole mass properties of local Seyfert galaxies
• NuSTAR Survey of Obscured Swift/BAT-selected Active Galactic Nuclei: II. Median High-energy Cutoff in Seyfert II Hard X-ray Spectra
• The properties of the AGN torus as revealed from a set of unbiased NuSTAR observations
• Compton-thick AGN in the NuSTAR era III: A systematic study of the torus covering factor
• The variable and non-variable X-ray absorbers in Compton-thin type-II Active Galactic Nuclei
• NuSTAR Observations of 52 Compton-thick Active Galactic Nuclei Selected by the Swift/BAT All-sky Hard X-Ray Survey
• Physically motivated X-ray obscurer models
• Inferring the morphology of AGN torus using X-ray spectra: A reliability study
• Properties of the Obscuring Torus in NGC 1052 from Multi-epoch Broadband X-ray Spectroscopy
• Star Formation Properties in Barred Galaxies(SFB). I. Ultraviolet-to-Infrared Imaging and Spectroscopic Studies of NGC 7479

Cited by in corpus (8)

• Neutrino signal from a population of Seyfert galaxies
• Hydrogen Column Density Variability in a Sample of Local Compton-Thin AGN
• Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN
• Compton-thick AGN in the NuSTAR Era X: Analysing seven local CT-AGN candidates
• The NuSTAR view of the changing look AGN ESO 323-G77
• A Multi-Wavelength Characterization of the Obscuring Medium at the Center of NGC 6300
• Chandra Follow-up Observations of Swift-BAT-selected AGNs III
• X-ray Spectral Variability as Probe of Multimessenger Emission in Blazar 5BZB J0630-24064