Monday, February 22, 2010

Testing Likelihood

I've been given the task to figure out why the likelihood method is missing QSOs that other methods are selecting.

I'm doing this by looking at QSOs from the 3PC (3%) catalog (see Feb 3rd email from Nic Ross). This file has the positions, redshifts, and targeting information for the objects.

I can get the psf_fluxes by doing a spherematch with the QSOs from the 3PC with the collated summery files (spAll-v5_4_5.fits) which have additional information for these objects. Nick gave me a trimmed file which I put on reimann: /home/jessica/boss/Single_objects_53839.dat which doesn't have duplicate entries for the same objects.

Below is a color-color diagram of the QSO catalog (green) and the everything else catalog (red). These are the catalogs we are using for calculating the likelihood:

Below is a color-color diagram of spectroscopically confirmed quasars which were targeted by the likelihood method (cyan) and missed by the likelihood method (magenta) on top of the normal star template (red) and quasar template (green):

As you would expect, we are missing objects which fall closer to the stellar locus. We can see this better when I plot the green QSO catalog with bigger points:

Looking at the straight psffluxes (which is what we calculate the likelihoods on). Below are plots of log-log plots of the psfflux for various color bands. The cyan points and quasars that the likelihood method targeted. The magenta points are quasars that the likelihood method didn't target (missed). This helps show regions in psfflux space where we do not have QSOs in our catalog which exist in the targeting data set.
u vs g
Below shows the above plot on top of the "everything" (red)
and "quasar" (green) catalogs used in the likelihood method.
u vs r

u vs i

u vs z
g vs r
g vs i

g vs z

r vs i
r vs z

i vz z

I think we should think about including some of these quasars in the inputs for the monte carlo so that we better cover these color regions.

I'm going to also plot where the mis-targeted stars are on these diagrams too.

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