Light curve model used?

[SCO]

Does AstroImageJ use a chi squared method to fit the observed data to a specific model such as "Mandel-Agol" or "Seager-Mallén-Ornelas"?  Or does it simply smooth out the individual chi squared inputs and then graph it?

[Rick_N.]

Page 13 of https://arxiv.org/pdf/1701.04817v1.pdf says:

4.4. Light Curve Fitting and Detrending
"The settings in the figure produce the light curve model fit shown in the example plot of Figure 7. The transiting exoplanet model is described in Mandel & Agol (2002). The transit is modeled as an eclipse of a spherical star by an opaque planetary sphere."

ASTROIMAGEJ: IMAGE PROCESSING AND PHOTOMETRIC EXTRACTION FOR ULTRA-PRECISE
ASTRONOMICAL LIGHT CURVES (EXPANDED EDITION)

I hope this helps

[SCO]

Thanks.  This helps me understand how the software is designed.

Ed

[Rick_N.]

Not wanting to presume much, but if you need any opinions on the magnitudes that you find I'd be happy to help :) When reporting Supernovae I've worked out the magnitudes over a hundred times, including a dozen or so using AIJ! Easy once you know how... I have no experience hunting exoplanets though and would not know how to report one as yet.

TNS
https://www.wis-tns.org/
https://www.wis-tns.org/object/2016jko

[SCO]

Thanks TNS for your offer of help.  As far as I know (which I admit is fairly limited at this point), there are two ways to draw a smooth graph based on emperical data; either do a simple chi squared analysis on it (very similar to least squared, but for nonlinear data), or use a model such as the one proposed by Mandel & Agol and adjust the parameters until the model fits the data points as closely as possible.  I prefer the second approach as the light curve would then be much more dependable.  Nevertheless, it is the more difficult of the two approaches.  I cannot see what AstroImageJ is doing under the covers, so I posted this question.  From the responses so far it sounds like AstroImageJ is taking the second approach based on the Mandel & Agol model.