Multifrequency Observations of the Galactic Microquasars GRS1915+105 and GROJ1655-40

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dc.creatorRemillard, Ronald A.
dc.creatorMorgan, Edward H.
dc.creatorMcClintock, Jeffrey E.
dc.creatorBailyn, Charles D.
dc.creatorOrosz, Jerome A.
dc.creatorGreiner, Jochen
dc.date1997-05-09
dc.date.accessioned2026-07-07T02:23:21Z
dc.date.available2026-07-07T02:23:21Z
dc.descriptionThe two galactic `microquasars' with superluminal radio jets have been quite active during 1996, generatinga variety of studies involving both NASA and ground-based observatories. GRS~1915+105 has displayed dramatic accretion instability in observations with RXTE, revealing X-ray light curves and emission states unlike anything previously seen. Variable QPOs in the range of 0.07--10 Hz have been monitored with the capability to track the individual oscillations. The QPO amplitude is as high as 40% of the mean flux, while both amplitude and phase lag increase with photon energy. The results imply a direct link between the QPO mechanism and the origin of the energetic electrons believed to radiate the X-ray power-law component. GRS1915+105 also displays a transient yet stationary QPO at 67 Hz. The other source, GRO J1655-40, is an optically established black hole binary. Recent optical reports include an excellent model for the binary inclination and masses, while an optical precursor to the April 1996 X-ray outburst has been measured. We report new results from recent RXTE observations. GROJ1655-40 has displayed both the canonical ``soft/high'' and ``very high'' X-ray states, with QPOs at 8--22 Hz during the latter state. In addition, there is a high-frequency QPO at 300 Hz. The rapid oscillations in these sources are suspected of providing a measure of the mass and rotation of the accreting black holes, although several competing models may be applied when evaluating the results.
dc.description8 pages Latex with 3 postscript figures.To be published in Proceedings of 18th Texas Symposium on Relativistic Astrophysics, held in Chicago, Dec. 1996, Eds. A. Olinto, J. Frieman, and D. Schramm, World Scientific Press
dc.identifierhttps://arxiv.org/abs/astro-ph/9705064
dc.identifierhttp://arxiv.org/abs/astro-ph/9705064
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/11218
dc.subjectAstrophysics
dc.titleMultifrequency Observations of the Galactic Microquasars GRS1915+105 and GROJ1655-40
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