Abstract
We report on XMM-Newton spectroscopic observations of the luminous, radio-quiet quasar PDS 456. The hard X-ray spectrum of PDS 456 shows a deep absorption trough (constituting 50% of the continuum) at energies above 7 keV in the quasar rest frame, which can be attributed to a series of blue-shifted K-shell absorption edges due to highly ionized iron. The higher resolution soft X-ray grating RGS spectrum exhibits a broad absorption line feature near 1 keV, which can be modeled by a blend of L-shell transitions from highly ionized iron (Fe XVII - XXIV). An extreme outflow velocity of approx. 50000 km/s is required to model the K and L shell iron absorption present in the XMM-Newton data. Overall, a large column density (N(sub H) = 5 x 10(exp 23)/sq cm) of highly ionized gas (log xi = 2.5) is required in PDS 456. A large mass outflow rate of approx. 10 solar mass/year (assuming a conservative outflow covering factor of 0.1 steradian) is derived, which is of the same order as the overall mass accretion rate in PDS 456. This represents a substantial fraction (approx. 10%) of the quasar energy budget, whilst the large column and outflow velocity place PDS 456 towards the extreme end of the broad absorption line quasar population.
Highlights
PDS 456 is a luminous low-redshift (z p 0.184) radio-quiet quasar identified in 1997 (Torres et al 1997)
An XMM-Newton observation of PDS 456 was subsequently obtained in AO-1, in order to obtain high signalto-noise spectra of both the iron K-shell complex with the European Photon Imaging Camera (EPIC) CCD detectors and a high-resolution spectrum of the soft X-ray absorber with the XMM-Newton Reflection Grating Spectrometer (RGS)
Data were taken with the EPICpn detector (Struder et al 2001) in full window mode and with the EPIC-MOS detector (Turner et al 2001) in large window mode
Summary
PDS 456 is a luminous low-redshift (z p 0.184) radio-quiet quasar identified in 1997 (Torres et al 1997). PDS 456 has a dereddened absolute blue magnitude of MB ≈ Ϫ27 (Simpson et al 1999), making it at least as luminous as the radio-loud quasar 3C 273. The X-ray spectrum of PDS 456, obtained by ASCA and RXTE, appeared to be unusual for a quasar. An XMM-Newton observation of PDS 456 was subsequently obtained in AO-1, in order to obtain high signalto-noise spectra of both the iron K-shell complex with the European Photon Imaging Camera (EPIC) CCD detectors and a high-resolution spectrum of the soft X-ray absorber with the XMM-Newton Reflection Grating Spectrometer (RGS). A previous paper (Reeves et al 2002) discussed in detail the X-ray variability during the XMM-Newton observation and a simultaneous week-long BeppoSAX observation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
