We present the analysis of four XMM–Newton observations of the narrow-line quasar PG 1543+489 at z = 0.400 carried out over a rest-frame time-scale of about 3 yr. The X-ray spectrum is characterized by a broad, relativistic iron Kα emission line and a steep photon index, which can be both explained by a ionized reflection model, where the source of X-ray photons is presumably very close to the black hole. If this were the case, strong light-bending effects are expected, and actually they provide the most plausible explanation for the large equivalent width (EW = 3.1 ± 0.8 keV in the source rest frame) of the iron line. Although the light-bending model provides a good description of the X-ray data of PG 1543+489, it is not possible to rule out an absorption model, where obscuring matter partially covers the X-ray source. However, the apparent lack of variations in the properties of the absorber over the time-scale probed by our observations may indicate that this model is less likely.
Vignali C., Piconcelli E., Bianchi S., Miniutti G. (2008). On the peculiar properties of the narrow-line quasar PG 1543+489. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 388, 761-769 [10.1111/j.1365-2966.2008.13438.x].
On the peculiar properties of the narrow-line quasar PG 1543+489
VIGNALI, CRISTIAN;
2008
Abstract
We present the analysis of four XMM–Newton observations of the narrow-line quasar PG 1543+489 at z = 0.400 carried out over a rest-frame time-scale of about 3 yr. The X-ray spectrum is characterized by a broad, relativistic iron Kα emission line and a steep photon index, which can be both explained by a ionized reflection model, where the source of X-ray photons is presumably very close to the black hole. If this were the case, strong light-bending effects are expected, and actually they provide the most plausible explanation for the large equivalent width (EW = 3.1 ± 0.8 keV in the source rest frame) of the iron line. Although the light-bending model provides a good description of the X-ray data of PG 1543+489, it is not possible to rule out an absorption model, where obscuring matter partially covers the X-ray source. However, the apparent lack of variations in the properties of the absorber over the time-scale probed by our observations may indicate that this model is less likely.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.