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Titolo:
Correlated X-ray spectral and timing behavior of the black hole candidate XTE J1550-564: A new interpretation of black hole states
Autore:
Homan, J; Wijnands, R; van der Klis, M; Belloni, T; van Paradijs, J; Klein-Wolt, M; Fender, R; Mendez, M;
Indirizzi:
Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands Univ Amsterdam Amsterdam Netherlands NL-1098 SJ J Amsterdam, Netherlands Natl Inst Nucl & High Energy Phys, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands Natl Inst Nucl & High Energy Phys Amsterdam Netherlands NL-1098 SJ lands MIT, Ctr Space Res, Cambridge, MA 02139 USA MIT Cambridge MA USA 02139MIT, Ctr Space Res, Cambridge, MA 02139 USA Osservatorio Astron Brera, I-23807 Merate, LC, Italy Osservatorio Astron Brera Merate LC Italy I-23807 23807 Merate, LC, Italy Univ Alabama, Dept Phys, Huntsville, AL 35899 USA Univ Alabama HuntsvilleAL USA 35899 Dept Phys, Huntsville, AL 35899 USA Natl Univ La Plata, Fac Ciencias Astron & Geofis, RA-1900 La Plata, Argentina Natl Univ La Plata La Plata Argentina RA-1900 A-1900 La Plata, Argentina
Titolo Testata:
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
fascicolo: 2, volume: 132, anno: 2001,
parte:, 1
pagine: 377 - 402
SICI:
0067-0049(200102)132:2<377:CXSATB>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
QUASI-PERIODIC OSCILLATIONS; INTERMEDIATE STATE; RXTE OBSERVATIONS; GX-339-4; VARIABILITY; GS-1124-683; DISCOVERY; BINARIES; NOISE; FLUX;
Keywords:
accretion, accretion disks; black hole physics; stars : individual (XTE J1550-564); X-rays : stars;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
63
Recensione:
Indirizzi per estratti:
Indirizzo: Homan, J Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands Univ Amsterdam Kruislaan 403 Amsterdam Netherlands NL-1098 SJ ds
Citazione:
J. Homan et al., "Correlated X-ray spectral and timing behavior of the black hole candidate XTE J1550-564: A new interpretation of black hole states", ASTROPH J S, 132(2), 2001, pp. 377-402

Abstract

We present an analysis of data of the black hole candidate and X-ray transient XTE J1550-564, taken with the Rossi X-Ray Timing Explorer between 1998November 22 and 1999 May 20. During this period the source went through several different states, which could be divided into soft and hard states based on the relative strength of the high-energy spectral component. These states showed up as distinct branches in the color-color and hardness-intensity diagrams, connecting to form a structure with a comblike topology, the branch corresponding to the soft state forming the spine and the branches corresponding to the various hard states forming the teeth of the comb. The power spectral properties of the source were strongly correlated with its position on the branches. The broadband noise became stronger and changed from power law-like to band-limited, as the spectrum became harder. Three types of quasi-periodic oscillations (QPOs) were found: 1-18 Hz and 102-284 HzQPOs on the hard branches, and 16-18 Hz QPOs on and near the soft branch. The 1-18 Hz QPOs on the hard branches could be divided into three subtypes. The frequencies of the high- and low-frequency QPOs on the hard branches were correlated with each other and were anticorrelated with spectral hardness. The changes in QPO frequency suggest that the inner disk radius only increases by a factor of 3-4 as the source changes from a soft to a hard state. Our results on XTE J1550-564 strongly favor a two-dimensional description of black hole behavior, where the regions near the spine of the comb in the color-color diagram can be identified with the high state, and the teethwith transitions from the high state, via the intermediate state (which includes the very high state) to the low state, and back. The two physical parameters underlying this two-dimensional behavior vary to a large extent independently and could for example be the accretion rate through the disk and the size of the Comptonizing region causing the hard tail. The differencebetween the various teeth is then associated with the mass accretion rate through the disk, suggesting that high state <----> low state transitions can occur at any disk mass accretion rate and that these transitions are primarily caused by another, independent parameter. We discuss how this picture could tie in with the canonical, one-dimensional behavior of black hole candidates that has usually been observed.
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Documento generato il 24/05/13 alle ore 19:13:17