THE TRIGONOMETRIC PARALLAX OF CYGNUS X-1
THE TRIGONOMETRIC PARALLAX OF CYGNUS X-1
We report a direct and accurate measurement of the distance to the X-ray binary Cygnus X-1, which contains the first black hole to be discovered. The distance of 1.86 (-0.11,+0.12) kpc was obtained from a trigonometric parallax measurement using the Very Long Baseline Array. The position measurements are also sensitive …