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LSST-nonproject / sims_maf_contrib

Contributed code for MAF (sims_maf)
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Metrics for depth+ebv limited analyses #72

Closed humnaawan closed 4 years ago

humnaawan commented 5 years ago

Here is a metric (egFootprintMetric) that implements a depth+ebv cut, needed for high S/N analysis for DESC static science.

Also included is an extension (depthLimitedNumGalMetric) of a previous metric (LSSObsStrategy/GalaxyCountsMetric_extended) that accounts for the depth+ebv cut when estimating the number of galaxies at a given redshift; note that this metric is not super relevant for DESC-LSS science (since we are way past the shot noise limit) but may be of interest for other science.

rhiannonlynne commented 5 years ago

Hi @humnaawan .. is this up to date and we can merge to master? Also - you say the depthLimitedNumGalMetric is not a useful metric for DESC-LSS science .. is the previous GalaxyCountMetric_extended relevant, or should that one also be marked not useful for DESC-LSS science? Does the new metric replace the previous metric?

humnaawan commented 4 years ago

@rhiannonlynne my apologies -- I should’ve used more accurate terminology than “not super relevant”. The Ngal metric is a statistical metric -- as I alluded to earlier, we are in a regime with O(10^9) galaxies, making statistical uncertainties for LSS be small. In contrast, however, the systematic uncertainties that arise from e.g. observing strategy artifacts are more pressing for LSS, making Ngal metric, while useful, not be of primary relevance for DESC-LSS. It will still be useful for, e.g., Galaxies SC where many science investigations are likely to be statistics-limited.

To further clarify, depthLimitedNumGalMetric is an extension of GalaxyCountMetric_extended as it accounts for S/N cuts (depth, ebv, all-band coverage for photo-z quality) that we plan to implement for LSS (and all static science); this is done by using egFootprintMetric to restrict to the survey area that passes the selection cuts before the number of galaxies is estimated.

rhiannonlynne commented 4 years ago

Merged PR from humnaawan:master