Tuesday, November 24, 2009

Commissioning Quasars

I am trying to answer these questions about the likelihood targets in the commissioning data. Today I took the collated targets for the QSO commissioning region from the wiki (here) and used spherematch to align it with the truth table that Nic Ross has provided me (based on visually inspected spectra). For truth table see the Nov 20th email from Ross with subject line BOSS Quasars "Truth Table." Both are also on riemann in the directory:
/home/jessica/boss/BOSS_QSOs_First14plates.fits
/home/jessica/boss/bosstarget-qso-comm-collate.fits
Target bitmasks from the wiki:
# restrictive qso selection
maskbits BOSS_TARGET1 10 QSO_CORE
# permissive qso selection
maskbits BOSS_TARGET1 11 QSO_BONUS
# known qso between [2.2,9.99]
maskbits BOSS_TARGET1 12 QSO_KNOWN_MIDZ
# known qso outside of miz range. never target
maskbits BOSS_TARGET1 13 QSO_KNOWN_LOHIZ
# Neural Net that match to sweeps/pass cuts
maskbits BOSS_TARGET1 14 QSO_NN
# UKIDSS stars that match sweeps/pass flag cuts
maskbits BOSS_TARGET1 15 QSO_UKIDSS
# kde targets from the stripe82 coadd
maskbits BOSS_TARGET1 16 QSO_KDE_COADD
# likelihood method
maskbits BOSS_TARGET1 17 QSO_LIKE
These are bitmasks, so in IDL to select items that are only selected by the likelihood method we would do the following:
LIKEONLY = where(truthmatch.BOSS_TARGET1 EQ ishft(long(1),17))

To select items which are selected by the likelihood (and others):

LIKE = where((truthmatch.BOSS_TARGET1 AND ishft(long(1),17)) GT 0)


To select items which are not selected by the likelihood (selected by others):

NOTLIKE = where((truthmatch.BOSS_TARGET1 AND ishft(long(1),17)) EQ 0)

To select objects with high redshift:

HIGHZ = where(truthmatch.Z_PERSON GT 3)


Below is a color-color plot of the above selections on top of the templates used for the likelihood selection. Red is everything. Green is QSOs. Magenta are objects that the likelihood method selected (LIKE). Cyan are objects that only the likelihood method selected (LIKEONLY). White are objects that have a high redshift (HIGHZ):

Color-Color (u-g vs g-r)
of likelihood selected objects

Below are objects that are QSOs but were missed by the likelihood (NOTLIKE). Need to figure out why.


Color-Color (u-g vs g-r)
of not-likelihood QSO objects

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