jluastro / PopSyCLE

Population Synthesis for Compact-object Lensing Events
https://popsycle.readthedocs.io/en/latest/
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delta magnitude technicality #39

Open caseylam opened 2 years ago

caseylam commented 2 years ago

I just realized while writing up some documentation, that there is something technically not right in PopSyCLE for the delta magnitude. The amplification is calculated using A = (u^2 + 2)/(u * sqrt(u^2 + 4)), with u = u0. But u0 is the closest approach in the heliocentric rectilinear frame, not the observed geocentric accelerating frame. So if you were an earthly observer (which, since we report piE's, seems logical), the calculated A will differ from the true maximum A. However, to get this right, we'd need to put in ephemerides into PopSyCLE, and also assign some type of absolute scale to t0 (which is completely arbitrary right now). I don't think we actually want to do that. So this "bug" doesn't necessarily requires any direct action/fixing, but just something to keep in mind.

Side question: I wonder if averages out between extra magnification and demagnification, so the delta mag is still right on average.