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Code Block
languagebash
themeMidnight
# On Garrawarla, test vcsbeam version
$ module use /pawsey/mwa/software/python3/modulefiles
$ module load vcsbeam
$ make_mwa_tied_array_beam -V
MWA Beamformer v2.18.8_99df2a4

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Code Block
languagebash
themeMidnight
$ cd /astro/mwavcs/asvo/251861
$ wget -O 1318345216.fits http://ws.mwatelescope.org/metadata/fits?obs_id=1318345216
$ cd /astro/mwavcs/vcs/1318345216/combined
$ for freq in {109..120}
do
    sed "s/FREQ/${freq}/" < make_legacy.sbatch > make_legacy_ch${freq}.sbatch
    sbatch make_legacy_ch${freq}.sbatch
done

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Code Block
languagebash
themeMidnight
title/astro/mwavcs/vcs/1318345216/vcsbeam/incoh/vcsbeam_incoh.sbatch
collapsetrue
#!/bin/bash -l

#SBATCH --nodes=12
#SBATCH --ntasks-per-node=1
#SBATCH --cpus-per-task=1
#SBATCH --mem=370gb
#SBATCH --partition=gpuq
#SBATCH --gres=gpu:1
#SBATCH --time=00:30:00
#SBATCH --account=mwavcs
#SBATCH --nice=0
#SBATCH --export=NONE
 
module use /pawsey/mwa/software/python3/modulefiles
module load vcsbeam
 
srun -N 12 -n 12 make_mwa_incoh_beam \
    -m /astro/mwavcs/vcs/1318345216/combined/1318345216_legacy.metafits \
    -b 1318345216 \
    -T 600 \
    -f 109 \
    -d /astro/mwavcs/vcs/1318345216/combined \
    -o incoh

Calibration

Offline Correlator

After beamforming finishes, fold on B0031-07:

Code Block
languagebash
themeMidnight
$ cd module load singularity
$ /astropawsey/mwavcsmwa/vcssingularity/1318345216/cal/1318345216/vis
$ for freq in {109..120}
do
    sed "s/FREQ/${freq}/" < offline_correlate.sbatch > offline_correlate_${freq}.sbatch
    sbatch offline_correlate_${freq}.sbatch
done
Code Block
languagebash
themeMidnight
titleoffline_correlate.sbatch
collapsetrue
#!/bin/bash -l

#SBATCH --nodes=1
#SBATCH --mem=370gb
#SBATCH --partition=gpuq
#SBATCH --gres=gpu:1
#SBATCH --time=01:00:00
#SBATCH --account=mwavcs
#SBATCH --export=NONE

module use /pawsey/mwa/software/python3/modulefiles
module load offline_correlator

for t in {0..599}
do

    gpssecond=$(echo "$t + 1318345216" | bc)
    gpubox=$(echo "FREQ - 108" | bc)

    INPUT_DATA_FILE=/astro/mwavcs/vcs/1318345216/combined/1318345216_${gpssecond}_chFREQ.dat
    START_SECOND=${gpssecond}
    DUMPS_PER_SECOND=1 # This sets the output time resolution
                    presto/presto.sif prepfold -psr J0034-0721 -nosearch -nodmsearch incoh*.fits

Image Added

The pulsar is clearly there, but there is a lot of RFI. After some experimenting, I find that the last 38% or so is RFI free:

Code Block
languagebash
themeMidnight
$ pawsey/mwa/singularity/presto/presto.sif prepfold -psr J0034-0721 -start 0.62 -nosearch -nodmsearch incoh*.fits

Image Added

Therefore, I should only use this section of the data to get a calibration solution.

Calibration

Offline Correlator

Code Block
languagebash
themeMidnight
$ cd /astro/mwavcs/vcs/1318345216/cal/1318345216/vis
$ for freq in {109..120}
do
    sed "s/FREQ/${freq}/" < offline_correlate.sbatch > offline_correlate_${freq}.sbatch
    sbatch offline_correlate_${freq}.sbatch
done


Code Block
languagebash
themeMidnight
titleoffline_correlate.sbatch
collapsetrue
#!/bin/bash -l

#SBATCH --nodes=1
#SBATCH --mem=370gb
#SBATCH --partition=gpuq
#SBATCH --gres=gpu:1
#SBATCH --time=01:00:00
#SBATCH --account=mwavcs
#SBATCH --export=NONE

module use /pawsey/mwa/software/python3/modulefiles
module load offline_correlator

for t in {0..599}
do

    gpssecond=$(echo "$t + 1318345216" | bc)
    gpubox=$(echo "FREQ - 108" | bc)

    INPUT_DATA_FILE=/astro/mwavcs/vcs/1318345216/combined/1318345216_${gpssecond}_chFREQ.dat
    START_SECOND=${gpssecond}
    DUMPS_PER_SECOND=1 # This sets the output time resolution
                    # (e.g. 20 --> 1/20 = 0.05s = 50 ms)
                    # Minimum allowed resolution is 2 ms
    CHANS_TO_AVERAGE=4 # This sets the output frequency resolution
                   # (e.g. 4 --> 4x10 kHz = 40 kHz)
    GPUBOX_CHANNEL_NUMBER=${gpubox} # This should be chosen to "match" the input channel
                         # This is not easy! (mwalib handles this, but at the
                         # moment, offline_correlator is not using mwalib)
    OUTPUT_PREFIX=1318345216 # Output files begin with this

    srun -N 1 -n 1 offline_correlator \
        -d ${INPUT_DATA_FILE} \
        -s ${START_SECOND} \
        -r ${DUMPS_PER_SECOND} \
        -n ${CHANS_TO_AVERAGE} \
        -c ${GPUBOX_CHANNEL_NUMBER} \
        -o ${OUTPUT_PREFIX}

done

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Code Block
languagebash
themeMidnight
title/astro/mwavcs/vcs/1318345216/cal/1318345216/rts/flagged_channels.txt
channels.txt
0
1
16
30
31

Selecting only the last 38% of the observation for calibration

One of the parameters passed to the RTS is the "basename" of the files containing the visibilities. In order to distinguish between the RFI-ridden visibilities and the clean ones, I will create soft links to the clean gpubox files (created in an earlier step) and change the case of the filenames (gpubox → GPUBOX). The first and last filenames are 1318345216_20111011150016_gpubox01_00.fits and 1318345216_20111011151015_gpubox12_00.fits, with the timestamp  in the format YYYYMMDDHHMMSS. To get the last 38%, I need to start 6:12 (mm:ss) into the observation, which means that my first clean file will be 1318345216_20111011150628_gpubox01_00.fits.

Code Block
languagebash
themeMidnight
titleCreate source list
$ cd /astro/mwavcs/vcs/1318345216/cal/1318345216/vis
$ ls 1318345216_2011101115062[89]_gpubox*.fits 1318345216_201110111506[3-5]?_gpubox*.fits 1318345216_20111011150[7-9]??_gpubox*.fits 1318345216_20111011151???_gpubox*.fits | while read f; do ln -s ${f} $(echo ${f} | tr 'gpubox' 'GPUBOX'); done

After doing this, the RTS ".in" file must be altered so that it's only looking for files with GPUBOX in the filename (see below).

Extra flags

After running the RTS (see below) and checking the solutions (using the python scripts supplied in VCSTools), I found that I also had to add 14 to the list of flagged channels, and 5253, 5459 and 61 to the list of flagged tiles.

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Code Block
languagebash
themeMidnight
title/astro/mwavcs/vcs/1318345216/cal/1318345216/rts/rts_1318345216.in
collapsetrue
ReadAllFromSingleFile=
BaseFilename=/astro/mwavcs/vcs/1318345216/cal/1318345216/vis/*_gpuboxGPUBOX
ReadGpuboxDirect=0
UseCorrelatorInput=1

ReadMetafitsFile=1
MetafitsFilename=/astro/mwavcs/vcs/1318345216/1318345216

DoCalibration=
doMWArxCorrections=1
doRawDataCorrections=1
doRFIflagging=0
useFastPrimaryBeamModels=0
generateDIjones=1
applyDIcalibration=1
UsePacketInput=0
UseThreadedVI=1

MaxFrequency=170.24
ObservationFrequencyBase=138.895
ObservationTimeBase=2455846.1252314816
ObservationPointCentreHA=-0.35952189154909175
ObservationPointCentreDec=-5.98757073636307
ChannelBandwidth=0.04
NumberOfChannels=32

CorrDumpsPerCadence=128
CorrDumpTime=1.0
NumberOfIntegrationBins=6
NumberOfIterations=1

StartProcessingAt=0

ArrayPositionLat=-26.7033194
ArrayPositionLong=116.6708152
ArrayNumberOfStations=128

ArrayFile=

SourceCatalogueFile=/astro/mwavcs/vcs/1318345216/cal/1318345216/srclist_pumav3_EoR0aegean_EoR1pietro+ForA_1318345216_patch1000.txt
NumberOfCalibrators=1
NumberOfSourcesToPeel=0
calBaselineMin=20.0
calShortBaselineTaper=40.0
FieldOfViewDegrees=1

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