SIMBAD references

BeppoSAX and ASCA observations of the nearby (z=0.184), high-luminosity, radio-quiet quasar PDS 456 are presented. The X-ray spectrum is characterized by a prominent ionized edge at 8-9keV (originally discovered by RXTE, Reeves et al., 20000MNRAS.312L..17R) and by a soft excess below 1.5keV. The lack of any significant iron Kα emission line suggests for the edge an origin from line-of-sight material rather than from reflection from a highly ionized accretion disc. The hard X-ray continuum is indeed well modelled by transmission through a highly-ionized medium with a large column density (N_Hwarm∼4.5x10²⁴cm^–2) plus an additional cold absorber with a lower column density (N_Hcold∼2.7x10²²cm^–2).