8th HEAD Meeting, 8-11 September, 2004
Session 15 Black Holes Binaries and Intermediate Mass Black Holes
Poster, Thursday, September 9, 2004, 9:00am-10:00pm

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[15.08] An Accretion-Jet Model for Black Hole Binaries: Interpreting the Spectral and Timing Features of XTE J1118+480

F. Yuan, W. Cui (Physics Department, Purdue University), R. Narayan (Harvard-Smithsonian CfA)

Simultaneous broadband observations of the black hole X-ray binary XTE J1118 + 480, ranging from radio, infrared, optical, UV, to X-ray, offer abundant spectral and timing information, and provide a challenge to theoretical models. We propose a coupled accretion-jet model to interpret the observations. We model the accretion flow as an outer standard thin accretion disk truncated at a transition radius by an inner radiatively inefficient accretion flow (RIAF). We find that the accretion flow alone substantially underpredicts the radio and infrared flux, even after we allow for nonthermal electrons in the RIAF. We thus require a jet to explain these components. We model the jet emission by means of the internal shock scenario which is widely employed for gamma-ray bursts. In our accretion-jet model of XTE J1118+480, the radio and infrared emission are dominated by the jet, the UV emission is dominated by the thin disk, and the X-ray emission is dominated by the RIAF. The optical emission has contributions from all three components: jet, thin disk, RIAF. Timing features, such as positive and negative optical-X-ray time lags, are explained naturally. This work was supported in part by NASA grants NAG5-9998 and NAG5-10780 and NSF grant AST-0307433.

The author(s) of this abstract have provided an email address for comments about the abstract: fyuan@physics.purdue.edu

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