BOSS Target Selection

Target Types

In BOSS there are four types of targets, which are described in more detail on the following pages:

Target selection is the process of selecting objects from the imaging survey for spectroscopic followup.

Target Runs Used in BOSS

A target run specifies both a target software version and a version of the data reductions. The following table contains information for the various runs of the targeting code. The tag version is marked BOSSTARGET_V. For information on tiling chunks, see the tiling page.

Target Run Version Info URLs Comments
main016
BOSSTARGET_V v2_0_18
IDLUTILS_V v5_4_24
PHOTOOP_V v1_10_26
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO ngc targets
QSO SGC targets
QSO bonus chunks
boss29-*.
main015
BOSSTARGET_V v2_0_18
IDLUTILS_V v5_4_24
PHOTOOP_V v1_10_25
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO SGC targets QSO chunk boss28
main014
BOSSTARGET_V v2_0_17
IDLUTILS_V v5_4_23
PHOTOOP_V v1_10_1
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC targets QSO chunk boss24-boss27
main013
BOSSTARGET_V v2_0_16
IDLUTILS_V trunk
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC targets
QSO SGC targets
QSO chunk boss19-boss23

A trunk version of idlutils was used but this has no affect on the targets

main012
BOSSTARGET_V v2_0_15a
IDLUTILS_V v5_4_24
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC targets
QSO SGC targets
QSO chunk boss18

These targets were actually bootstrapped from main011 due to some disk failures at LBL.

main011
BOSSTARGET_V v2_0_15
IDLUTILS_V v5_4_24
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC target file
QSO SGC target file
QSO chunk boss17
main010
BOSSTARGET_V v2_0_14
IDLUTILS_V v5_4_22
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC target file
QSO SGC target file
QSO chunk boss16
These files include targets selected using multi-epoch photometry, when available. First chunk where new UKIDSS information is also included in the ExD processing when available, which is in turn used in the NN combinator.
main009
BOSSTARGET_V v2_0_13
IDLUTILS_V v5_4_24
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
LRG target file LRGs for chunk boss15-* targeted from this run. This differs from main008 in the limit ifiber2mag – extinction < 21.5
main008
BOSSTARGET_V v2_0_9
IDLUTILS_V v5_4_20
PHOTOOP_V v1_10_2
PHOTO_SWEEP dr8_final
PHOTO_RESOLVE 2010-05-23
PHOTO_CALIB dr8_final
QSO NGC target file
QSO edfinal
QSO SGC target file
LRG target file
LRG chunks boss12-boss14
QSO chunks boss12-boss13 using “sgc40” subset.

QSO chunk boss14 using “edcore-maskngc40” and bootstrapped from main008 using code in BOSSTARGET v2_0_12. This file was mistakenly used instead of edfinal-maskngc40; edcore is actually trunk but has the same targets. Should reference edfinal in the future.

QSO chunk boss15 uses subset file edfinal-maskngc40

STD chunks boss12-*

main007
BOSSTARGET_V v2_0_5
IDLUTILS_V v5_4_13
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-11-16.v2
PHOTO_RESOLVE 2009-11-16
PHOTO_CALIB fall09i
LRG target file LRGs for Chunk boss7-boss11 targeted from this run.
main006
BOSSTARGET_V v2_0_4
IDLUTILS_V v5_4_11
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-11-16.v2
PHOTO_RESOLVE 2009-11-16
PHOTO_CALIB fall09i
QSO NGC target file
QSO SGC target file
Chunk boss7-boss10 QSOs targeted from this run.ngc, masked for bad u data.

Subset file “maskngc”, which masks out the bad u-band data, was used for boss7 but this is not *stated* in the plan-boss7.par file.

Subset file “masksgc1” was used for boss9 Unlike “maskngc”, this does not mask out bad data, but rather restricts to a smaller chunk of the SGC.

Subset file “maskngc” was used for boss10.

In principle “maskngc” should have been used for boss8 but I think it was not needed since the target area was further north than the “bad” u data runs.

main005
BOSSTARGET_V v2_0_3
IDLUTILS_V v5_4_11
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-11-16.v2
PHOTO_RESOLVE 2009-11-16
PHOTO_CALIB fall09i
QSO target file
LRG target file
STD target file
For QSO,LRG chunks boss5+boss6 targeted from this run.For STD chunks boss5-boss11 targeted from this run.
No cut on calib_status.
Full survey available at that time.
main004
BOSSTARGET_V v2_0_2
IDLUTILS_V v5_4_11
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-11-16
PHOTO_RESOLVE 2009-06-14
PHOTO_CALIB default0
STD target file Chunks boss3+boss4 STD targeted from this run.
main002
BOSSTARGET_V v2_0_1
IDLUTILS_V v5_4_11
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-11-16
PHOTO_RESOLVE 2009-06-14
PHOTO_CALIB default0
QSO target file
LRG target file
Chunks boss3+boss4 QSO and LRG targeted from this run.No cut on calib_status.
comm2
BOSSTARGET_V v1_1_2
IDLUTILS_V v5_4_9
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-09-28
PHOTO_RESOLVE 2009-06-14
PHOTO_CALIB default0
QSO target file
LRG target file
STD target file
Chunk boss2 LRG+QSO+STD
comm
BOSSTARGET_V v1_0_4
IDLUTILS_V v5_4_7
PHOTOOP_V v1_9_4
PHOTO_SWEEP 2009-06-14
PHOTO_RESOLVE 2009-06-14
PHOTO_CALIB default0
QSO target file
LRG target file
STD target file
Chunk boss1 LRG+QSO+STD

Targeting Software

Targets lists for galaxies, quasars and standards were generated using a unified software framework bosstarget. This code can be checked out from the svn repository

 svn export http://www.sdss3.org/svn/repo/boss/bosstarget/tags/{tag} bosstarget-{tag}

Where {tag} represents a “tagged” version of the code. Targets used for BOSS spectroscopic followup are always generated using a tagged version of bosstarget

To run the code, make sure the PHOTO_SWEEP environment variable points to the location of your copy of the datasweeps Similarly, make sure PHOTO_RESOLVE points to the relevant resolve files and PHOTO_CALIB points to the relevant calib files.

Then the following IDL commands will execute targeting for a particular set of imaging runs and camcols

 IDL> bt=obj_new('bosstarget') IDL> bt->self->process_runs, target_type, target_run,  $ runs=runs, camcols=camcols

where target_type is ‘lrg’,’qso’,’std’ and target_run is an arbitrary string. There are more options documented in the code. The ->process_partial_runs method can be used to process a set of runs. The targets can then be collated into a single file using ->gather or the partial sets using ->gather_partial.

After the collation, appropriate BOSS_TARGET1 flags can be applied to limit to a smaller subset of targets.

For QSOs a further trimming is applied in order to limit the target density to 40/sq degree in “cells” on the sky. This code is in /pro/bosstarget_util.pro in the ->subreg_density_tune.

Variability Selected Targets

The variability selected catalog used for quasars in chunk boss11 is described in Palanque-Delabrouille et al. 2011