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High-Resolution Spectroscopy of the X-Ray–photoionized Wind in Cygnus X-3 with the [ITAL]Chandra[/ITAL] High-Energy Transmission Grating Spectrometer

2000; IOP Publishing; Volume: 533; Issue: 2 Linguagem: Inglês

10.1086/312608

1538-4357

F. Paerels, J. Cottam, M. Šako, D. A. Liedahl, A. C. Brinkman, R. L. J. van der Meer, J. S. Kaastra, P. Predehl,

Astronomical Observations and Instrumentation

We present a preliminary analysis of the 1-10 keV spectrum of the massive X-ray binary Cygnus X-3, obtained with the high-energy transmission grating spectrometer on the Chandra X-Ray Observatory. The source reveals a richly detailed discrete emission spectrum, with clear signatures of photoionization-driven excitation. Among the spectroscopic novelties in the data are the first astrophysical detections of a number of He-like "triplets" (Si, S, Ar) with emission-line ratios characteristic of photoionization equilibrium, fully resolved narrow radiative recombination continua of Mg, Si, and S, the presence of the H-like Fe Balmer series, and a clear detection of an approximately 800 km s-1 large-scale velocity field as well as an approximately 1500 km s-1 FWHM Doppler broadening in the source. We briefly touch on the implications of these findings for the structure of the Wolf-Rayet wind.