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Further Evidence For Variable Synchrotron Emission In Xte J1118+480 In Outburst, R. I. Hynes, E. L. Robinson, K. J. Pearson, D. M. Gelino, W. Cui, Y. Q. Xue, M. A. Wood, T. K. Watson, D. E. Winget, I. M. Silver
Further Evidence For Variable Synchrotron Emission In Xte J1118+480 In Outburst, R. I. Hynes, E. L. Robinson, K. J. Pearson, D. M. Gelino, W. Cui, Y. Q. Xue, M. A. Wood, T. K. Watson, D. E. Winget, I. M. Silver
Faculty Publications
We present simultaneous multicolor infrared and optical photometry of the black hole X-ray transient XTE Jill 8+480 during its short 2005 January outburst, supported by simultaneous X-ray observations. The variability is dominated by short timescales, ∼10 s, although a weak superhump also appears to be present in the optical. The optical rapid variations, at least, are well correlated with those in X-rays. Infrared JHKS photometry, as in the previous outburst, exhibits especially large-amplitude variability. The spectral energy distribution (SED) of the variable infrared component can be fitted with a power law of slope α = -0.78 ± 0.07, where Fν …
Multiwavelength Observations Of Exo 0748-676. I. Reprocessing Of X-Ray Bursts, R. I. Hynes, Keith Horne, K. O'Brien, C. A. Haswell, E. L. Robinson, A. R. King, P. A. Charles, K. J. Pearson
Multiwavelength Observations Of Exo 0748-676. I. Reprocessing Of X-Ray Bursts, R. I. Hynes, Keith Horne, K. O'Brien, C. A. Haswell, E. L. Robinson, A. R. King, P. A. Charles, K. J. Pearson
Faculty Publications
We present high time-resolution multi wavelength observations of X-ray bursts in the low-mass X-ray binary UY Vol. Strong reprocessed signals are present in the ultraviolet and optical, lagged and smeared with respect to the X-rays. The addition of far-ultraviolet coverage for one burst allows much tighter constraints on the temperature and geometry of the reprocessing region than previously possible. A blackbody reprocessing model for this burst suggests a rise in temperatures during the burst from 18,000 to 35,000 K and an emitting area comparable to that expected for the disk and/or irradiated companion star. The lags are consistent with those …
Multiwavelength Observations Of Exo 0748-676. Ii. Emission-Line Behavior, K. J. Pearson, R. I. Hynes, D. Steeghs, P. G. Jonker, C. A. Haswell, A. R. King, K. O'Brien, G. Nelemans, M. Méndez
Multiwavelength Observations Of Exo 0748-676. Ii. Emission-Line Behavior, K. J. Pearson, R. I. Hynes, D. Steeghs, P. G. Jonker, C. A. Haswell, A. R. King, K. O'Brien, G. Nelemans, M. Méndez
Faculty Publications
We present optical and ultraviolet spectra, light curves, and Doppler tomograms of the low-mass X-ray binary EXO 0748-676. Using an extensive set of 15 emission-line tomograms, we show that, along with the usual emission from the stream and "hot spot," there is extended nonaxisymmetric emission from the disk rim. Some of the emission and Ha and Hβ absorption features lend weight to the hypothesis that part of the stream overflows the disk rim and forms a two phase medium. The data are consistent with a 1.35 M ⊙ neutron star with a main-sequence companion and hence a mass ratio q …
Numerical Simulations Of The Onset And Stability Of Dynamical Mass Transfer In Binaries, Mario C.R. D'Souza, Patrick M. Motl, Joel E. Tohline, Juhan Frank
Numerical Simulations Of The Onset And Stability Of Dynamical Mass Transfer In Binaries, Mario C.R. D'Souza, Patrick M. Motl, Joel E. Tohline, Juhan Frank
Faculty Publications
Hydrodynamical simulations of semidetached, polytropic binary stars are presented in an effort to study the onset and stability of dynamical mass transfer events. Initial, synchronously rotating equilibrium models are constructed using a self-consistent field technique and then evolved with an Eulerian hydrodynamics code in a fully self-consistent manner. We describe code improvements introduced over the past few years that permit us to follow dynamical mass transfer events through more than 30 orbits. Mass transfer evolutions are presented for two different initial configurations: a dynamically unstable binary with initial mass ratio (donor/accretor) q 0 = 1.3 that leads to a complete …