2001/07/31 by J. M. Mïller, J. M. Miller, R. Wijnands +7
Physics and Astronomy · #Accretion (finance) #Accretion disc #Advection #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Context (archaeology) #Flux (metallurgy) #Galaxy #Gamma-ray bursts and supernovae #Intermediate polar #Luminosity #Physics #Pulsars and Gravitational Waves Research #Spectral line #Stars #White dwarf #astro-ph
paper · pdf · doi:10.1086/338038
14 pages, 4 figures (3 in color), ApJ accepted Oct. 1 2001
arxiv created 2001/10/01 · openalex publication_date 2002/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We report on an XMM-Newton Reflection Grating Spectrometer observation of the black hole candidate and Galactic microquasar GRS 1758-258. The source entered a peculiar "off/soft" state in 2001 late February in which the spectrum softened while the X-ray flux—and the inferred mass accretion rate—steadily decreased. We find no clear evidence for emission or absorption lines in the dispersed spectra, indicating that most of the observed soft flux is likely from an accretion disk and not from a cool plasma. The accretion disk strongly dominates the spectrum in this lower luminosity state and is only mildly recessed from the marginally stable orbit. These findings may be difficult to explain in terms of advection-dominated accretion flow (ADAF) models. We discuss these results within the context of ADAF models, simultaneous two-flow models, and observed correlations between hard X-ray flux and jet production.