Line Spectrum from Accretion-Disk Winds
Prompted by the discovery of pair-annihilation lines in Nova Muscae 1991, we calculated the emission line spectra of optically thin winds emanating from the inner region of a geometrically thin accretion disk. The line profiles are generally double peaked, partly due to the configuration of the winds, and partly due to the rotational motion of the winds. Blue peaks are enhanced due to the Doppler beaming. The lines are broad when the emission region is in the vicinity of the disk where the rotation is large, whereas they are narrow when the emission height is far from the disk. Furthermore, the line-center is generally shifted blueward due to the Doppler effect, except for the case with high inclination angles, in which the transverse redshift (plus gravitational redshift) overcomes the Doppler blueshift. The model profiles were compared with the observed pair-annihilation lines in X-ray Nova Muscae 1991, which showed the red-shifted linecenter. If the annihilation lines of Nova Muscae originated from the (pair) winds from the inner accretion disks, we can thus conclude that the emission height would be several tens of the Schwarzschild radius, and that the disk is nearly edge-on to observers.
- PASJ : publications of the Astronomical Society of Japan
PASJ : publications of the Astronomical Society of Japan 47(5), 639-643, 1995-10-25
Astronomical Society of Japan