Complex X-Ray Absorption and the Fe Kα Profile in NGC 3516
Abstract
We present data from simultaneous Chandra, XMM-Newton, and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and November. We have investigated the nature of the very flat observed X-ray spectrum. Chandra grating data show the presence of X-ray absorption lines, revealing two distinct components of the absorbing gas, one that is consistent with our previous model of a UV/X-ray absorber while the other, which is outflowing at a velocity of ~1100 km s-1, has a larger column density and is much more highly ionized. The broadband spectral characteristics of the X-ray continuum observed with XMM-Newton during 2001 April reveal the presence of a third layer of absorption consisting of a very large column (~2.5×1023 cm-2) of highly ionized gas with a covering fraction ~50%. This low covering fraction suggests that the absorber lies within a few light days of the X-ray source and/or is filamentary in structure. Interestingly, these absorbers are not in thermal equilibrium with one another. The two new components are too highly ionized to be radiatively accelerated, which we suggest is evidence for a hydromagnetic origin for the outflow. Applying our model to the November data set, we can account for the spectral variability primarily by a drop in the ionization states of the absorbers, as expected by the change in the continuum flux. When this complex absorption is accounted for, we find the underlying continuum to be typical of Seyfert 1 galaxies. The spectral curvature attributed to the high column absorber in turn reduces estimates of the flux and the extent of any broad Fe emission line from the accretion disk.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2005
- DOI:
- 10.1086/425961
- arXiv:
- arXiv:astro-ph/0409091
- Bibcode:
- 2005ApJ...618..155T
- Keywords:
-
- Galaxies: Active;
- Galaxies: Individual: NGC Number: NGC 3516;
- Galaxies: Nuclei;
- Galaxies: Seyfert;
- X-Rays: Galaxies;
- Astrophysics
- E-Print:
- 33 pages, 9 figures, accepted for publication in ApJ