Black hole spin in GRS 1915+105

摘要: Microquasars are galactic black hole binary systems with radio jets which can sometimes be spatially resolved to show superluminal motion. The first and best known of this class objects is GRS 1915+105, the brightest accreting source in our Galaxy. There persistent speculation that strong jet emission could linked spin. If so, high spin should also evident accretion disc spectra. We search RXTE archive find disc-dominated X-ray spectra from object, as these only ones give reliable determinations by method. Finding complicated rapid, unique limit cycle variability, but we able identify such going shortest possible time resolution (16 s). fit them a simple multicolour blackbody (DISKBB), current model include full radiative transfer well relativistic effects (BHSPEC). Both models intermediate, neither zero nor maximal. BHSPEC, most physical model, gives value for dimensionless a* ∼0.7 distance 12.5 kpc inclination 66°. This, together range spins 0.1 < a· 0.8 derived using method other holes, suggests probably fundamentally powered gravity rather than spin, implies high-to-maximal not pre-requisite powerful jets.