Simultaneous NuSTAR and XMM–Newton 0.5–80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654

Feb 28, 2014
10 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 440 (2014) 3, 2347-2356
  • Published: May 21, 2014
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Abstract: (Oxford University Press)
We present a broad-band spectral analysis of the joint XMM–Newton and Nuclear Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM–Newton orbits. We detect a relativistic broadened iron Kα line originating from the innermost regions of the accretion disc surrounding the central black hole, from which we infer an intermediate spin of a=0.580.17+0.11a = 0.58^{+0.11}_{-0.17}. The intrinsic spectrum is steep (Γ = 2.08 ± 0.01) as commonly found in narrow-line Seyfert 1 galaxies, while the cutoff energy (Ec=10810+11E_{\rm c}=108^{+11}_{-10} keV) falls within the range observed in broad-line Seyfert 1 galaxies. We measure a low-frequency lag that increases steadily with energy, while at high frequencies, there is a clear lag following the shape of the broad Fe K emission line. Interestingly, the observed Fe K lag in SWIFT J2127.4+5654 is not as broad as in other sources that have maximally spinning black holes. The lag amplitude suggests a continuum-to-reprocessor distance of about 10–20 r_g. These timing results independently support an intermediate black hole spin and a compact corona.
Note:
  • 11 pages, 10 figures, accepted for publication on MNRAS
  • accretion, accretion discs
  • galaxies: active
  • galaxies: individual: SWIFT J2127.4+5654
  • galaxies: Seyfert