GISMO Data Reduction

Contents

  1. GISMO Data Reduction
    1. Basic reduction
    2. Filtering options
    3. Skydip reduction

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Basic reduction

To reduce GISMO data with crush, first log into your project account: 

ssh -X 078-13@mrt-lx2.iram.es

Raw data are stored in the directory ~/observationData/gismo. The scans are stored in a filing hierarchy, organised by source name, then an IRAM scan ID composed of a UT calendar date and a scan number. For example, the scan 113 taken on 2013-04-12 of NGC4449 is stored as: 

~/observationData/gismo/NGC4449/2013-04-12.113/NGC4449_2013-04-12.113_gismo.fits

To reduce this scan with crush, type in your terminal: 

crush gismo -default                           \
            -datapath=~/observationData/gismo  \ 
            -object=NGC4449                    \
            -date=2013-04-12 113               \
            -outpath=~/crush_reduction         \
            -name=NGC449

It is possible to add several scans: 

crush gismo -default                           \
            -datapath=~/observationData/gismo  \ 
            -object=NGC4449                    \
            -date=2013-04-12 113-116 120       \
            -date=2013-04-13 1-6               \
            -outpath=~/crush_reduction         \
            -name=NGC4449

and also to combine different source-names: 

crush gismo -default                           \
            -datapath=~/observationData/gismo  \
            -object=NGC4449                    \
            -date=2013-04-12 113-116 120       \
            -object=NGC4449-N                  \
            -date=2013-04-14 21-23             \
            -outpath=~/crush_reduction         \
            -name=NGC4449

Filtering options

Just replace -default by one of the following options:

-deep

deep fields when the most aggressive filtering of common mode is done

-extended

for structures larger than the field-of-view

-faint

faint sources (S/N<10)

-bright

bright sources (S/N>1000)

You may also want to use combinations like e.g. -faint -extended.

Don't forget that Attila Kovacs wrote good CRUSH documentation.

Skydip reduction

crush gismo -skydip                            \
            -skydip.elRange=25:50              \
            -datapath=~/observationData/gismo  \
            -object=TipCurrentAzimuth          \
            -date=2013-04-26 99                \
            -outpath=~/crush_reduction         \
            -name=skydip.2013.04.26.99

Author: Israel Hermelo (IRAM 30m continuum pool manager)

email: hermelo@iram.es

Created: 2013.10.25

Last update: 2013.10.25