AAS 201st Meeting, January, 2003
Session 57. Stellar Black Holes
Oral, Tuesday, January 7, 2003, 10:00-11:30am, 6AB

## [57.02] Spectroscopy of Cyg X-1 the High State with HETG/Chandra

Y.X. Feng (UAH/MSFC), A. Tennant (MSFC), S.N. Zhang (UAH/MSFC)

Cyg X-1 was observed in the high state around orbital phase 0 with HETG/Chandra. Significant absorption lines of highly ionized species were detected, such as Fe XXV, Fe XXIV, Fe XXIII, S XIV, S XVI, Ne X, etc. The observed absorption lines are found to be blue-shifted (z ~ -0.002) from those observed in the low and transition states. In the high state each absorption line was composed of a blue-shifted absorption line and a un-shifted absorption line which similar to that observed in the low state. The broad line feature of Fe K\alpha at 6.4 keV was detected with a significance of \Delta \chi2 ~40, although precise measurements are hindered by uncertainties in the calibration. The implications of these results on the configuration of the accretion flow of Cyg X-1 in the high state are discussed.

Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.