English

The NuSTAR view of reflection and absorption in NGC 7582

High Energy Astrophysical Phenomena 2015-12-16 v1

Abstract

NGC 7582 is a well-studied X-ray bright Seyfert 2 with moderately heavy (NH10231024N_{\text{H}}\sim10^{23}-10^{24}~cm2^{-2}), highly variable absorption and strong reflection spectral features. The spectral shape changed around the year 2000, dropping in observed flux and becoming much more highly absorbed. Two scenarios have been put forth to explain this spectral change: 1) the central X-ray source partially ``shut off'' around this time, decreasing in intrinsic luminosity, with a delayed decrease in reflection features due to the light-crossing time of the Compton-thick material or 2) the source became more heavily obscured, with only a portion of the power law continuum leaking through. NuSTAR observed NGC~7582 twice in 2012, two weeks apart, in order to quantify the reflection using high-quality data above 10 keV. We find that the most plausible scenario is that NGC 7582 has recently become more heavily absorbed by a patchy torus with a covering fraction of 8090%\sim\,80-90\% and an equatorial column density of 3×1024\sim 3 \times10^{24} cm2^{-2}. We find the need for an additional highly variable full-covering absorber with NH=46×1023N_{\text{H}}= 4-6 \times10^{23} cm2^{-2} in the line of sight, possibly associated with a hidden broad line region.

Keywords

Cite

@article{arxiv.1511.01951,
  title  = {The NuSTAR view of reflection and absorption in NGC 7582},
  author = {E. Rivers and M. Baloković and P. Arévalo and F. E. Bauer and S. E. Boggs and W. N. Brandt and M. Brightman and F. E. Christensen and W. W. Craig and P. Gandhi and C. J. Hailey and F. Harrison and M. Koss and C. Ricci and D. Stern and D. J. Walton and W. W. Zhang},
  journal= {arXiv preprint arXiv:1511.01951},
  year   = {2015}
}

Comments

Accepted to ApJ, Nov 2015