Paper was dense. Still doing some looking on light echoes, etc. Hopefully will understand more from the Historic Transients paper.
Wondering if we could go into a bit more depth about light-echo analysis and how it is used, etc. That is, how it works to visualize something from the 19th century as in this paper. How does light produce an "echo"?
Was also wondering about the Eddington Luminosity Limit. What is this?
The paper mentions how the authors used cross-correlation with "G-type templates" to determine velocities - which I assume to be wind velocities. First off, are the velocities actually wind velocities? Second, how does one derive the G-type template? That is, what models go into using it?
Lastly, wondering if we can talk about the eruptions. I understand some of the causes are uncertain. Wondering if we can explain a bit more about what we do know. Seems strange, the luminosity would just 'randomly' increase. What may cause this?