Open AccessXMM–Newton spectroscopy of high‐redshift quasars
Author(s) -
Page K. L.,
Reeves J. N.,
O'Brien P. T.,
Turner M. J. L.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09550.x
Subject(s) - quasar , physics , astrophysics , redshift , rest frame , astronomy , quiet , emission spectrum , radio galaxy , ovv quasar , spectral line , galaxy
XMM–Newton observations of 29 high‐redshift ( z > 2) quasars, including seven radio‐quiet, 16 radio‐loud and six broad absorption line (BAL) objects, are presented; due to the high redshifts, the rest‐frame energy bands extend up to ∼30–70 keV. Over 2–10 keV, the quasars can be well fitted in each case by a simple power law, with no strong evidence for iron emission lines. The lack of iron lines is in agreement both with dilution by the radio jet emission (for the radio‐loud quasars) and the X‐ray Baldwin effect. No Compton reflection humps at higher energies (i.e. above 10 keV in the rest frame) are detected either. Over the broad‐band (0.3–10 keV), approximately half (nine out of 16) of the radio‐loud quasars are intrinsically absorbed, with the values of N H generally being 1 × 10 22 to 2 × 10 22 cm −2 in the rest frames of the objects. None of the seven radio‐quiet objects shows excess absorption, while four of the six BAL quasars are absorbed. The radio‐loud quasars have flatter continuum slopes than their radio‐quiet counterparts ( Γ RL ∼ 1.55; Γ RQ ∼ 1.98 over 2–10 keV), while, after modelling the absorption, the underlying photon index for the six BAL quasars is formally consistent with the non‐BAL radio‐quiet objects.