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Title: Deconvolving X-ray spectral variability components in the Seyfert 1.5 NGC 3227

We present the variability analysis of a 100 ks XMM-Newton observation of the Seyfert 1.5 active galaxy, NGC 3227. The observation found NGC 3227 in a period where its hard power-law component displayed remarkably little long-term variability. This lucky event allows us to clearly observe a soft spectral component undergoing a large-amplitude but slow flux variation. Using combined spectral and timing analysis, we isolate two independent variable continuum components and characterize their behavior as a function of timescale. Rapid and coherent variations throughout the 0.2-10 keV band reveal a spectrally hard (photon index Γ ∼ 1.7-1.8) power law, dominating the observed variability on timescales of 30 ks and shorter. Another component produces coherent fluctuations in the 0.2-2 keV range and is much softer (Γ ∼ 3); it dominates the observed variability on timescales greater than 30 ks. Both components are viewed through the same absorbers identified in the time-averaged spectrum. The combined spectral and timing analysis breaks the degeneracy between models for the soft excess: it is consistent with a power-law or thermal Comptonized component but not with a blackbody or an ionized reflection component. We demonstrate that the rapid variability in NGC 3227 is intrinsic to continuum-emitting components andmore » is not an effect of variable absorption.« less
Authors:
 [1] ;  [2]
  1. Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Casilla 306, Santiago 22 (Chile)
  2. Center for Astrophysics and Space Sciences, University of California, San Diego, Mail Code 0424, La Jolla, CA 92093-0424 (United States)
Publication Date:
OSTI Identifier:
22351588
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; AMPLITUDES; FLUCTUATIONS; KEV RANGE; PHOTONS; REFLECTION; SEYFERT GALAXIES; SPECTRA; X-RAY GALAXIES