BOSS Target Selection

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

Target Types

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

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. Confirm?

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