A possible ultra strong and broad Fe Kα emission line in seyfert 2 galaxy IRAS 00521-7054

Abstract

We present XMM-Newton spectra of the Seyfert 2 Galaxy IRAS 00521-7054. A strong feature at 6keV (observer's frame) can be formally fitted with a strong (EW = 1.3 ± 0.3keV in the rest frame) and broad Fe Kα line, extending down to 3keV. The underlying X-ray continuum could be fitted with an absorbed power law (with Γ = 1.8 ± 0.2 and N H = 5.9+0.6-0.7 × 1022cm-2) plus a soft component. If due to relativistically smeared reflection by an X-ray illuminated accretion disk, the spin of the supermassive black hole (SMBH) is constrained to be 0.97+0.03-0.13 (errors at 90% confidence level for one interesting parameter), and the accretion system is viewed at an inclination angle of 37° 4°. This would be the first type 2 active galactic nucleus reported with strong red Fe Kα wing detected which demands a fast rotating SMBH. The unusually large EW would suggest that the light bending effect is strong in this source. Alternatively, the spectra could be fitted by a dual-absorber model (though with a global χ2 higher by 6 for 283 dof) with N H1 = 7.0 ± 0.8 × 1022cm-2 covering 100% of the X-ray source, and N H2 = 21.7+5.6-5.4 × 10 22cm-2 covering 71%, which does not require an extra broad Fe Kα line. © 2012 The American Astronomical Society. All rights reserved.