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Record 1 of 18516
Hard X-ray spectra of neutron stars and black hole candidates
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Author and Affiliation:
Durouchoux, P.(Commissariat a l'Energie Atomique, Saclay France)
Mahoney, W.(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Clenet, Y.(Commissariat a l'Energie Atomique, Saclay France)
Ling, J.(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Wallyn, P.(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Wheaton, W.(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Corbet, S.(Commissariat a l'Energie Atomique, Saclay France)
Chapuis, C.(Commissariat a l'Energie Atomique, Saclay France)
Abstract: The hard X-ray behavior of several X-ray binary systems containing a neutron star or a black hole candidate is analyzed in an attempt to determine the specific signature of these categories of compact objects. Limiting the consideration to two subclasses of neutron stars, Atoll sources and non-pulsating Z sources, it appears that only the Atoll sources have a spectral behavior similar to black holes. It is proposed that Atoll sources are weakly magnetized neutron stars, whereas Z sources are small radius moderate magnetized neutron stars. Large magnetic fields funnel the accreting matter, thus preventing spherical accretion and free fall if the neutron star radius is smaller than the last stable accreting orbit. Weak magnetic fields do not have this effect, and blackbody soft photons from the stellar surface are upscattered on the relativistic infalling matter, leading to excess hard X-rays. This excess is visible in two of the observed Atoll sources and in the spectrum of a black hole candidate. In the case of a Z source, a lack of photons was remarked, providing a possible signature to distinguish between these classes of objects.
Publication Date: Mar 01, 1997
Document ID:
19970025748
(Acquired Sep 10, 1997)
Accession Number: 97N25218
Subject Category: ASTRONOMY
Document Type: Conference Paper
Publication Information: Proceedings of 2nd INTEGRAL Workshop 'The Transparent Universe'; 137-139; (ESA-SP-382); (SEE 19970025721)
Financial Sponsor: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA United States
Organization Source: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA United States
Description: 3p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: NEUTRON STARS; BLACK HOLES (ASTRONOMY); X RAY SPECTRA; X RAY BINARIES; MAGNETIC FIELDS; MAGNETIC STARS; STELLAR MAGNETIC FIELDS; STELLAR MASS ACCRETION; CLASSIFICATIONS
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