ctools

Since source flux is only an important measure for point sources (and small sources), it might be worthwhile to think about adding the surface brightness for extended sources (i.e. source flux divided by source solid angle). For the analyses of short time windows, large structures with high flux (but low surface brightness) could be neglected and increase the speed of the analysis.

Not sure though if this would complicate the tool too much...

Mayer Michael wrote:

Since source flux is only an important measure for point sources (and small sources), it might be worthwhile to think about adding the surface brightness for extended sources (i.e. source flux divided by source solid angle). For the analyses of short time windows, large structures with high flux (but low surface brightness) could be neglected and increase the speed of the analysis.

Not sure though if this would complicate the tool too much...

I agree that this would be useful, but for the moment the models do provide a method that provides the solid angle of the model. It would certainly be useful to add such a method to the GModelSpatial class. I added feature #1880 for this.

I guess this could simply be mediated by the method GModelSpatial::region()::solidangle(), right?

Mayer Michael wrote:

I guess this could simply be mediated by the method GModelSpatial::region()::solidangle(), right?

There is just one problem: GModelSpatial::region() returns for the moment a bounding circle which encloses the model, and this bounding circle can be larger than the model (it’s actually full sky for the composite model and the diffuse cube; for a map it is a bounding circle around a rectangular map).

For the GModelSpatial::solidangle() we would like to have the solid angle that matches the model. By the way: it’s a bit tricky to define the solid angle for a Gaussian model. We may rather want to have a kind of equivalent solid angle of the model (the bounding circle is 5 times the Gaussian sigma for a Gaussian model).