The Structure Of The Accretion Disk In The ADC Source 4U 1822-371

Date
2010-07
Authors
Bayless, A. J.
Robinson, E. L.
Hynes, R. I.
Ashcraft, T. A.
Cornell, M. E.
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Abstract

The low-mass X-ray binary (LMXB) 4U 1822-371 has an accretion disk corona (ADC) that scatters X-ray photons from the inner disk and neutron star out of the line of sight. It has a high orbital inclination and the secondary star eclipses the disk and ADC. We have obtained new time-resolved UV spectrograms and V- and I-band photometry of 4U 1822-371. The large quadratic term in our new optical eclipse ephemeris confirms that the system has an extremely high rate of mass transfer and mass accretion. The C IV lambda lambda = 1548 - 1550 angstrom emission line has a half width of similar to 4400 km/s, indicating a strong, high velocity wind is being driven off the accretion disk. Near the disk the wind is optically thick in UV, V, and J and the eclipse analysis shows that in V and J the optically thick wind extends nearly to the outer edge of the disk. The ADC must also extend vertically to a height equal to approximately half the disk radius.

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Citation
Amanda J. Bayless, Edward L. Robinson, Robert I. Hynes, Teresa A. Ashcraft, and Mark E. Cornell. AIP Conference Proceedings 1248, 141 (Jul., 2010); doi: 10.1063/1.3475169