Doppler tomography - precession of a disc leading to changes in observed spectrum

This shows an example of the method of Doppler tomography. This is similar to a CT scan, where images of the inside of an object are produced from a collection of 1D "slices". Using spectra, which are 1D velocity slices, we can build up an image of a disc in velocity space using these slices. The image shown here is a map generated by spectra collected from the gaseous debris disc around the white dwarf SDSSJ1228+1040. The spectrum on the right is generated for an observer viewing the disc from the bottom of the figure. Generating the spectrum on the right from the Doppler map for a particular orientation is explained in this video    • Doppler tomography - Going from velocity i...