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Long-term Multi-wavelength Observations of GRS 1758-258 and the ADAF Model

John W. Keck·William W. Craig·Charles J. Hailey·Fiona Harrison·Jae Sub Hong·Steven M. Kahn·Philip M. Lubin·Ryan McLean·Michael J. Pivovaroff·Michael Seiffert·Ron Wurtz·Klaus P. Ziock
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Abstract

We present a long-term multi-wavelength light curve of Galactic black hole candidate GRS 1758-258 by combining previously published and archival data from GRANAT, ROSAT, CGRO, RXTE, SAX, ASCA, EXOSAT, and the VLA. In addition we include first spectral results from the balloon-borne Gamma-ray Arcminute Telescope Imaging System (GRATIS). In light of divergent analyses of the 1991-1993 ROSAT observations, we have re-analyzed these data; we find the soft X-rays track the hard X-rays, and that the fits require no black-body component-- indicating that GRS 1758-258 did not go to the high state in 1993. We offer an interpretation based on the ADAF model for a system with mdot \ltsim mdot_crit. We find the 1990-1993 coeval hard and soft X-ray observations support the ADAF predictions. We discuss a new way to constrain black-hole mass with spectral data and the ADAF theory, and apply this technique to GRS 1758-258 to find M_1 \gtsim 8--9 M_sol at an assumed distance of 8.5 kpc. Further investigations of the ADAF model allow us to evaluate the model critically against the data and flux-flux diagram of Barret, McClintock & Grindlay (1996) and to understand the limits of the latter's ``X-ray burster box.''

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John W. Keck, William W. Craig, Charles J. Hailey, Fiona Harrison, Jae Sub Hong, Steven M. Kahn, Philip M. Lubin, Ryan McLean, Michael J. Pivovaroff, Michael Seiffert, Ron Wurtz, Klaus P. Ziock. 2001-08-07. Long-term Multi-wavelength Observations of GRS 1758-258 and the ADAF Model. https://doi.org/10.1086/323686

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