Superbroad Component in Emission Lines of SS 433

Abstract

We have detected new components in stationary emission lines of SS 433; these are the superbroad components that are low-contrast substrates with a width of 2000--2500 km s-1 in He I $\lambda 4922$ and H$\beta$ and 4000--5000 km s-1 in He II $\lambda 4686$. Based on 44 spectra taken during four years of observations from 2003 to 2007, we have found that these components in the He II and He I lines are eclipsed by the donor star; their behavior with precessional and orbital phases is regular and similar to the behavior of the optical brightness of SS 433. The same component in H$\beta$ shows neither eclipses nor precessional variability. We conclude that the superbroad components in the helium and hydrogen lines are different in origin. Electron scattering is shown to reproduce well the superbroad component of H$\beta$ at a gas temperature of 20--35 kK and an optical depth for Thomson scattering $\tau \approx$ 0.25--0.35. The superbroad components of the helium lines are probably formed in the wind from the supercritical accretion disk. We have computed a wind model based on the concept of Shakura-Sunyaev supercritical disk accretion. The main patterns of the He II line profiles are well reproduced in this model: not only the appearance of the superbroad component but also the evolution of the central two-component part of the profile of this line during its eclipse by the donor star can be explained.

17 pages, 13 figures, 2 tables, published in Astronomy Letters, 2013, vol. 39, N 12, pp. 826 - 843

References in corpus (3)

• Super-critically accreting stellar-mass black holes as ultraluminous X-ray sources
• Spectroscopic Observations of the Mass Donor Star in SS 433
• Diagnostics of the black hole candidate SS433 with the RXTE

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• Diagnostics of Parameters for the X-ray Jets of SS 433 from High-Resolution Chandra Spectroscopy
• The Spectrum of SS 433 in the H and K Bands