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X-ray absorption toward the red quasar 3C 212
(IOP Publishing, 1994)
A Roentgen Satellite (ROSAT) X-ray spectrum of the z = 1.049 'red quasar' 3C 212 has a strong low-energy cutoff. The spectrum can be fitted with a power law (of energy index 1.4(+0.8, -0.6) with low-energy photoelectric ...
Absorption in X-ray spectra of high-redshift quasars
(IOP Publishing, 1994)
We present evidence that X-ray absorption is common in high-redshift quasars. We have studied six high-redshift (z approximately 3) quasars with the ROSAT Position Sensitive Proportional Counter (PSPC) of which four are ...
The complex optical to soft x-ray spectrum of the low-redshift radio-quiet quasars
(IOP Publishing, 1994)
Eight high signal-to-noise ROSAT Position Sensitive Proportional Counter (PSPC) observations of six low-redshift (o.048 less than z less than 0.155) radio-quiet quasars have been analyzed to study ant soft excess. All the ...
PKS 0483-436 - A high-redshift quasar with strong X-ray absorption
(IOP Publishing, 1992)
The first X-ray spectrum of a high-redshift (z = 2.85) quasar is reported. The Rosat PSPC spectrum of PKS 0438-436, covering 0.3-9 keV in the quasar's rest frame, reveals unexpected absorption of about 1 x 10 exp 22/sq cm, ...
Infrared to x-ray spectral energy distributions of high redshift quasars
(IOP Publishing, 1994)
We have observed 14 quasars with z greater than 2.8 with the ROSAT-PSPC, and detected 12 of them, including the z=4.11 quasar 0000-263. We present the first x-ray spectrum of a radio quiet quasar with z greater than 3, ...
X-ray spectral evolution of high redshift quasars
(IOP Publishing, 1994)
At z approx. equals 3, the x-ray spectra of radio-loud and radio-quiet quasars are different. High-redshift radio-quiet quasars either have large absorbing columns, NH, and steeper power law spectral indices, alphaepsilon, ...
The soft x-ray properties of a complete sample of optically selected quasars. 1: First results
(IOP Publishing, 1994)
We present the results of ROSAT position sensitive proportional counter (PSPC) observations of 10 quasars. These objects are part of our ROSAT program to observe a complete sample of optically selected quasars. This sample ...