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Effects of cold matter in active galactic nuclei - A broad hump in the X-ray spectra
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1988
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Active galactic nuclei contain cold, thermal matter coexisting with hot X‑ray emitting plasma near their centers, as inferred from strong UV emission. The study aims to use the reprocessed X‑ray spectrum to diagnose the physical conditions and energy source of this cold material. Reprocessing of X‑rays by the cold matter produces a broad spectral hump between ~10 keV and ~300 keV, bounded below by atomic absorption and above by electron scattering. Observed AGN spectra show a hump consistent with this prediction, with an amplitude of ~0.1–0.5, but higher‑precision data are required. Published in The Astrophysical Journal, December 1988 (DOI 10.1086/166905).
view Abstract Citations (576) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Effects of Cold Matter in Active Galactic Nuclei: A Broad Hump in the X-Ray Spectra Lightman, Alan P. ; White, Timothy R. Abstract Recent observations and interpretations of the strong UV emission from active galactic nuclei (AGNs) suggest that relatively cold, thermal matter coexists with the hot, X-ray-emitting matter near the centers of these objects. A fraction of the X-rays will be reprocessed by the cold material, and the composite X-ray spectrum should help diagnose the conditions of this material and its energy source. In a variety of situations, reprocessing of the X-rays should lead to a composite X-ray spectrum with a broad hump between ~10 keV and ~300 keV. The lower limit of this energy range is determined by atomic absorption and the upper limit by electron scattering in the cold material. Where available, observed spectra are consistent with such a broad hump; however, the predicted amplitude of the hump is ~0.1-0.5, and observations with smaller error bars are clearly needed. Publication: The Astrophysical Journal Pub Date: December 1988 DOI: 10.1086/166905 Bibcode: 1988ApJ...335...57L Keywords: Active Galactic Nuclei; Astronomical Spectroscopy; Dark Matter; Spectral Energy Distribution; X Ray Spectra; Black Holes (Astronomy); Optical Thickness; Spectrum Analysis; Astrophysics; GALAXIES: NUCLEI; X-RAYS: SPECTRA full text sources ADS | data products SIMBAD (3) NED (3)