Question

I'd like to query LS DR10 sources that are close to the survey detection limit; can you please show me which flags to use to ensure I get decent photometry? In addition, I found that if I use conditions to filter data from more than one band at the same time, the search time increases significantly compared to filtering only one band. Is this normal?

Answer 1

Just responding to the second part of your question: Could you please provide the full query you are trying to run?

Answer 2

The detection threshold can be found in ls_dr10.tractor.dchisq_1, where (PSF) sources with ls_dr10.tractor.dchisq_1 near 25 will be near our 5-sigma detection limit (summed across all optical bands).  So one could choose 25 < ls_dr10.tractor.dchisq_1 < 49 to get those sources between 5- and 7-sigma detection.