TY - JOUR
T1 - The discovery of broad p cygni x-ray lines from circinus x-1 with the Chandra high-energy transmission grating spectrometer
AU - Brandt, W. N.
AU - Schulz, N. S.
N1 - Funding Information:
We thank all the members of the Chandra team for their enormous efforts, and we thank J. Chiang, A. C. Fabian, S. C. Gallagher, S. Kaspi, R. A. Wade, and an anonymous referee for helpful discussions. We gratefully acknowledge the financial support of CXC grant GO0-1041X (W. N. B. and N. S. S.), the Alfred P. Sloan Foundation (W. N. B.), and Smithsonian Astrophysical Observatory contract SV1-61010 for the CXC (N. S. S.).
PY - 2000/12/1
Y1 - 2000/12/1
N2 - We present the first grating-resolution X-ray spectra of the X-ray binary Circinus X-1, obtained with the High-Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or Helike Ne, Mg, Si, S, and Fe detected with a high signal-to-noise ratio. The lines are broad (±2000 km s-1) and show P Cygni profiles. The absorption components of the lines extend to low velocity, and they have about the same widths and strengths as the corresponding emission components. The widths of the X-ray P Cygni lines are comparable to that of the broad component of the strong, asymmetric Hα line from Cir X-1. suggesting that the two phenomena may be related. We discuss outflow models and propose that the P Cygni profiles may arise in the moderate temperature (∼5 × 106 K) region of the wind from an X-ray-heated accretion disk. This basic picture strengthens the idea that the accretion disk in Cir X-1 is viewed in a relatively edge-on manner, and it suggests that Cir X-1 is the X-ray binary analog of a broad absorption line quasar.
AB - We present the first grating-resolution X-ray spectra of the X-ray binary Circinus X-1, obtained with the High-Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or Helike Ne, Mg, Si, S, and Fe detected with a high signal-to-noise ratio. The lines are broad (±2000 km s-1) and show P Cygni profiles. The absorption components of the lines extend to low velocity, and they have about the same widths and strengths as the corresponding emission components. The widths of the X-ray P Cygni lines are comparable to that of the broad component of the strong, asymmetric Hα line from Cir X-1. suggesting that the two phenomena may be related. We discuss outflow models and propose that the P Cygni profiles may arise in the moderate temperature (∼5 × 106 K) region of the wind from an X-ray-heated accretion disk. This basic picture strengthens the idea that the accretion disk in Cir X-1 is viewed in a relatively edge-on manner, and it suggests that Cir X-1 is the X-ray binary analog of a broad absorption line quasar.
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U2 - 10.1086/317313
DO - 10.1086/317313
M3 - Article
AN - SCOPUS:0034548972
SN - 0004-637X
VL - 544
SP - L123-L127
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2 PART 2
ER -