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Akn 564: an unusual component in the x-ray spectra of nlsy1 galaxies
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Turner, T. J. Netzer, Hagai George, I. M. |
| Copyright Year | 1999 |
| Description | We present an ASCA observation of the narrow-line Seyfert l (NLSyl) Arakelian 564. The X-ray light curve shows rapid variability, but no evidence for energy-dependence to these variations, within the 0.6 - 10 keV bandpass. A strong (EW approximately 70 eV) spectral feature is observed close to 1 keV. A similar feature has been observed in TON S180, another member of the NLSyl class of objects, but has not been observed in broad-line Seyfert galaxies. The feature energy suggests a large contribution from Fe L-shell lines but its intensity is difficult to explain in terms of emission and/or absorption from photoionized gas. The models which predict most emission at 1 keV are characterized by extreme values of column density, Fe abundance and ionization parameter. Models based on gas in thermal equilibrium with kT approximately l keV provide an alternative parameterization of the soft spectrum. The latter may be interpreted as the hot intercloud medium, undergoing rapid cooling and producing strong Fe L-shell recombination lines. In all cases the physical conditions are rather different from those observed in broad-line Seyferts. The hard X-ray spectrum shows a broad and asymmetric Fe K(alpha) line of large equivalent width (approximately 550 eV) suggestive of significant emission from the inner accretion disk. The profile can be explained by a neutral disk viewed at approximately 60 deg to the line-of-sight, contrary to the hypothesis that NLSyls are viewed pole-on. The large EW of this line, the strong 1 keV emission and the strong optical Fe emission lines all suggest an extreme Fe abundance in this and perhaps other NLSyls. |
| File Size | 818735 |
| Page Count | 16 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19990103950 |
| Archival Resource Key | ark:/13960/t9b61hk71 |
| Language | English |
| Publisher Date | 1999-01-01 |
| Access Restriction | Open |
| Subject Keyword | Astronomy Seyfert Galaxies Light Emission Emission Spectra Variability Satellite Observation Light Curve X Ray Spectra X Ray Astronomy Parameterization Accretion Disks Thermodynamic Equilibrium Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
