Detections above mag 23

I have a set of fake sources with magnitudes in the range [18, 27] inserted in all calexps containing the area. I ran the LSST stack (twice) on the dataset according to the tutorial (The LSST Science Pipelines — LSST Science Pipelines). I obtain all “deepcoadd_forced_src” detections in the area and the coadd from the corresponding patch. I plot the coadd and the detections (I’ve attached the PNG) and I see that there are no detections of fakes with mag >= 24 and only some detections of mag = 23.5.

I’ve generated the fakes using the modified add_fake_sources method from the stack where fake sources are generated like this:

f = calexp.getPhotoCalib().magnitudeToInstFlux(magnitude, wcs.skyToPixel(spoint))
fake = galsim.DeltaFunction().withFlux(f)

Do you have any idea why the faint fakes aren’t getting detected? Is this really the limit or there might be some other catch?


I found the solution. Lowering the detection.thresholdValue parameter in DRP.yaml makes the pipeline detect more objects. It was set to 260 sigma for some reason.