Measurement of X-ray iron line emission from Cygnus X-3 with the OSO 8 crystal spectrometer

The earliest Uhuru observations showed that cluster X-ray sources were not associated with single individual galaxies but were extended sources (Gursky et al. 1971, Kellogg et al. 1972, and Forman et al. 1972). The detection of iron line emission from X-ray spectroscopic observations (Mitchell et al. 1976 and Serlemitsos et al. 1977) showed both that the dominant X-ray emission process was thermal bremsstrahlung and that the gas had been processed through stellar systems before being injected into the intracluster medium.

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Exosat Observations of H2252−035: Pulse Phase and Orbital Phase Dependent Low Energy Absorption and Iron Line Emission

International Astronomical Union Colloquium ◽

10.1017/s0252921100104993 ◽

1987 ◽

Vol 93 ◽

pp. 281-292

Author(s):

W. Pietsch ◽

W. Voges ◽

E. Kendziorra ◽

M. Pakull

Keyword(s):

Energy Absorption ◽

Line Emission ◽

Low Energy ◽

Gas Absorption ◽

X Rays ◽

Medium Energy ◽

Iron Line ◽

X Ray ◽

Low Energies ◽

Optical Light Curve

AbstractThe 805 sec pulsing X-ray source H2252−035 has been observed for 7 h on September 14/15 and on September 17, 1983 in X-rays with the low energy telescope and the medium energy detectors of EXOSAT. While below 2 keV the semiamplitude of the 805 s pulses is ~ 100% in the 2.3–7.9 keV band it is only ~ 40%. X-ray dips that are more pronounced in low energies occur simultaneously with the orbital minimum of the optical light curve. The medium energy spectra during dips with respect to the non dip spectrum can be explained by just enhanced cold gas absorption of an additional absorbing column of 2 1022 cm−2. Model spectra for the 805 s minimum have to include a strong iron emission line at 6.55 keV with an equivalent width of 3 keV in addition to a reduced continuum intensity (radiating area) and enhanced low energy absorption.

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Iron Line Emission from NGC1068

Symposium - International Astronomical Union ◽

10.1017/s0074180900140707 ◽

1989 ◽

Vol 134 ◽

pp. 167-172

Author(s):

Katsuji Koyama

Keyword(s):

Energy Range ◽

Power Law ◽

Equivalent Width ◽

Line Emission ◽

X Rays ◽

Iron Line ◽

X Ray ◽

Central Engine ◽

Photon Index ◽

The Continuum

X-ray emission in the 2–10 keV energy range was observed with the Ginga satellite from the Seyfert 2 galaxy NGC1068. The continuum spectrum can be described by a power-law of photon index about 1.5. An intense iron line at 6.5 keV with an equivalent width of 1.3 keV was clearly noticed. The X-ray flux was about 6 × 10 −12 erg/sec/cm2 or 3 × 1041 erg/sec, assuming a distance of 22 Mpc. The observed spectrum is consistent with the scattering and reprocessing of X-rays by the gas surrounding the central engine. With this picture we estimate that the X-ray flux of the central engine is about 1043 - 1044 erg/sec, a typical value for a Seyfert 1 galaxy.

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