Comment by 20k

>I don't see "simplified" as being opposite to "accurate".

Are black hole accretion disks generally red in real astrophysical cases?

They're most accurately represented as being blue. Red is fine for visualisations because it looks cool (which is fine!), but blue is the physically accurate colour. Visualisations claiming to be accurate like this presenting red black holes is becoming an increasingly large science communication problem

The way that the colour and brightness are mapped together is also not correlated correctly, and some of the equations just aren't right. The doppler isn't correct at all here, partly because its simulated incorrectly (with the camera problems), and partly because the mapping done at the end doesn't correlate to any reasonable brightness

Stuff like this: Its not accurate at all. It isn't simplified, its just wrong - which is totally fine for a visualisation, if that's the intent. But:

>scales like logarithmic are very common in scientific images.

Sure. What scale are you using for the doppler brightness here? Because as far as I can tell, its a piecewise mapping of the form ~pow(x, 2.2), after being run through a non smooth function `afmhot` - a function which doesn't have a linear brightness response. So the brightness in this image doesn't really correspond to anything related to doppler or brightness, and the colour also doesn't correspond to anything involving colour (or the doppler). The entire image's look is basically accidental

Here's a specific comment from the event horizon telescope talking about exactly this problem with specifically the afmhot transform being used, because its important for visualisation:

https://github.com/achael/eht-imaging/issues/85

Which shows some of the problems here