I've been playing with the single epoch likelihoods cross checked with the truth table. The rest of the targeting will be on single epoch measurements (i.e. not stripe 82) so these are a more accurate measurement of how well the likelihood is doing. I've been playing with adjusting various parameters like how we define "variability" in terms of the chi^2 cut, if we should add variable objects from the L_everything catalog to L_QSO.

Below are the raw numbers of quasars targeted (normalized to targeting of ~40/degree^2) as well as the accuracy of each method:

No variability Method

; number quasars

1029

;percent accuracy

0.545986

; total targeted

1881

Variable objects with chi^2 > 1.5 subtracted from L_everything

; number quasars

1047

;percent accuracy

0.556619

; total targeted

1881

Variable objects with chi^2 > 1.5 subtracted from L_everything

Variable objects with chi^2 > 1.5 added to L_QSO

; number quasars

1033

;percent accuracy

0.549176

;total targeted

1881

Variable objects with chi^2 > 1.1 subtracted from L_everything

; number quasars

1053

;percent accuracy

0.559809

; total targeted

1881

Variable objects with chi^2 > 1.2 subtracted from L_everything

; number quasars

1055

;percent accuracy

0.560872

; total targeted

1881

Variable objects with chi^2 > 1.3 subtracted from L_everything

; number quasars

1054

;percent accuracy

0.560340

; total targeted

1881

Variable objects with chi^2 > 1.4 subtracted from L_everything

; number quasars

1051

;percent accuracy

0.558745

; total targeted

1881

Variable objects with chi^2 > 1.2 subtracted from L_everything

Variable objects with chi^2 > 1.6 added to L_QSO

; number quasars

1036

;percent accuracy

0.550771

;total targeted

1881

Variable objects with chi^2 > 1.2 subtracted from L_everything

Variable objects with chi^2 > 1.5 added to L_QSO

; number quasars

1035

;percent accuracy

0.550239

;total targeted

1881

Variable objects with chi^2 > 1.2 subtracted from L_everything

Variable objects with chi^2 > 1.4 added to L_QSO

; number quasars

1034

;percent accuracy

0.549708

;total targeted

1881

Variable objects with chi^2 > 1.2 subtracted from L_everything

Variable objects with chi^2 > 1.3 added to L_QSO

; number quasars

1029

;percent accuracy

0.547049

;total targeted

1881

It seems that the method with the best accuracy (56%) is variable objects with chi^2 > 1.2 subtracted from L_everything.

Here is a plot of the L_everything (non variable) vs L_QSO:

Magenta objects are targeted QSOs.

Cyan objects are targeted stars.

Green objects are not targeted stars.

Red objects are missed qsos.

It looks like we might be able to make the L_ratio a function of L_QSO to perhaps pick up a few more of the red objects at the top right corner.

Another interested plot is looking at likelihood-ratio vs g-band flux:

The color scheme is the same as first plot

We might be able to get more missed QSOs (red) if we target faint (g-flux less than 5) objects with a L_ratio close to the cut. I've also plotted likelihood-ratio vs g-r magnitude:

To download file directly from web using the command line:

wget http://www.downloadingurl.com/filetodownload.fits

If it is from a password protected page (like the wiki) then do the following:

wget --http-user=myusername --http-password=mypassword http://www.downloadingurl.com/filetodownload.fits

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