6dF: Observing, data reduction

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6dF Observing, data reduction dataflow

• Q.A.Parker
• Macquarie University/AAO

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Talk outline

• Brief summary of observing procedure
• 6dF data reduction with 6dFdr runz
• Dataflow

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Current 6dF observing team

• Malcolm Hartley (observing management)
• Paul Cass (6dFdr)
• Ken Russell
• Fred Watson
• Dionne James (Bessell BOM programme)
• Will Saunders (post commissioning development,
  observing)
• Other 6dfsag members/qap as required

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Standard 6dF Observing process

• Selection of tiles from latest tiling run
  sufficient to cover night/run
• Consistent directory structure and field naming
  conventions ensures no confusion of input files,
  configure files etc for each nights observations
• Potential targets cross-checked against SCOS
  image thumbnails to remove contaminants prior to
  configuration
• .fld files created for each cleaned tile
  pointing includes merging in of suitable
  Tycho-2 guide stars
• 6dfconfigure run on .fld files for given field
  plate (takes into account broken fibres etc)

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Standard 6dF .fld file structure

• comment line - 6dF field configuration file (an
  ascii file)
• LABEL target field number 1 xyz cluster
• UTDATE 2002 05 27
• EQUINOX J2000.0
• CENTRE 12 43 23.30 -10 34 10.0
• end of required header info
• these are fiducial star positions
• F1 12 40 20.55 -10 30 11.4 F 9 12.0 1
  brightest star
• F2 12 38 10.31 -09 59 58.9 F 9 13.5 1
  fiducial star
• these are target object positions
• NGC1002 12 41 30.55 -10 31 56.9 P 2 15.0 1
  galaxy target
• ic3082 12 40 18.40 -10 32 21.5 P 2 17.0 1
  galaxy target
• PHR1232 12 32 26.5 -09 58 26.4 P 2 16.6 1
  galaxy target
• .
• . etc up to 200 say
• these are checked blank sky positions
• sky-1 12 40 10.20 -10 32 21.5 S 5 99.9 1
  blank sky (checked)
• sky-2 12 39 11.5 -09 58 45.6 S 5 99.9 1
  blank sky (checked)

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Observing process cont.

• Once field configuration has been tested the
  output configuration (.sds file) is input to the
  robot configure software
• Configuration typically takes an hour for a full
  150 fibre field
• If possible first 2 fields will have been
  prepared earlier in the afternoon with the first
  ready to go before the end of astronomical
  twilight
• Availability of two field plates enables one to
  be configured whilst the other is being observed
• 20-30 minutes are needed to mount each fibred 6dF
  field plate in the telescope, take dome
  flat-fields and arc frames and for acquiring the
  field on the sky.
• Acquire both 600V (1 hr) and 316R (0.5hr)
  observations for each field
• 5 fields per night have been achieved during the
  winter lunations and 3 are possible in the summer
  lunations

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6dF R-theta robot and field plate
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Data acquisition via 6dF CICADA

• CICADA has been customised for 6dF in the
  following ways
• A 6dF instrument configuration plug-in added
• An interface to the UK Schmidt TEL_CONTROL built
  as a TCS plug-in
• A FITS plug-in written to insert 6dF BINTABLE
  extensions describing the 6dF instrument
  configuration

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6dF commissioning data frame
Emission lines
Night sky lines
Blue region
Red region
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6dFdr creating 1-D calibrated spectra

• Directly analogous to 2dFdr has same basic
  functionality and very similar GUI
• Specifically modified to work with 6dF data
  frames by Jeremy Bailey (AAO)
• After some development now offers a relatively
  stable platform for reduction on standard 6DFGRS
  data almost as a black box
• Care needs to be taken with the observations to
  ensure trouble free processing through the 6dfdr
  package

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Running 6dFdr

• Requires at least 1 Flat field frame, 1 arc frame
  and 3 or more data frames
• 6dfdr runs on Starlink sdf files so need to
  convert from cicada output fits images (tool
  available e.g. fits2ndf)
• Once 6dfdr is launched simply a question of going
  to setup menu select prefix identifying
  frames in the run
• Select the Flat field - reduce it - check tram
  line fitting is o.k.
• Select the Arc - reduce Arc
• Select data frames reduce data frames
• Combine the individual reduced data frames
• Plot spectra from combined reduced frames to
  check o.k.
• Exit 6dfdr and cleanup all unwanted files

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316R data
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RUNZ semi-automated Z determinations

• Modified version of the code developed
  principally by Will Sutherland for the 2dFGRS.
• Offers a convenient mechanism for interactive
  redshift estimation from 1-D 6dfdr reduced
  spectra
• Some extra functionality offered by WS/QAP
• Currently need to reduce the 600V and 316R data
  separately though are plans to splice the 2
  slightly overlapping regions together after
  attempting flux-calibration
• Still needs modifications to make it run more
  smoothly with 6dfdr reduced data (was developed
  for and works better with a wider wavelength
  coverage than 600V and 316R provide alone).

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Can autofit to selected lines
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6dF WWW interface form of data product

• The www interface will provide access to
  the reduced survey data in the form of object
  parameters for each object together with their
  associated reduced 6dF spectra. For each
  observed object we would provide a minimum of
• object ID position (J2000 ra,dec) optional
  l,b
• 2MASS J,H,K photometry (with errors),
• DENIS I-band magnitude (with error)
• classification/spectral type (e.g. galaxy, AGN,
  stellar contaminant etc)
• redshift, z error, optical magnitude
• structural image information from the SCOS
  optical parameter lists
• fully reduced 1-D spectra
• Basic ancillary information for each entry such
  as date of observation, grating, 6dF field plate,
  fibre number etc
•  

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Higher dispersion 600V data

• Additionally the velocity dispersions from the
  600V data would include
• most of the above parameters plus measurements
  (with errors) of
•        
• velocity dispersion line indices,
• galaxy diameters,
• distance estimates
• peculiar velocities.
• The www interface would permit all (or a
  selection) of the object parameters to be
• down-loaded including an option to down-load the
  associated 1-D spectra.
• The interface would also permit direct access to
  the raw/partially processed
• image frames via a suitable query system and
  survey field map.
• It is estimated that 3 months of software effort
  would be required to produce such an
• interface based On PERL scripts.

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Dataflow to Database

• Final details still to be sorted
• Involves assimilation of reduced spectra AND
  redshift/peculiar velocity results into the
  current master results catalogue
• Results catalogue contains observed objects from
  the master input catalogue

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WFAU 6dF involvement includes

• Involvement in survey data products management
• commissioning support (qap - done)
• help with target catalogue construction (mar/qap
  done)
• archival of survey data products
• community access to the data products via
  development of suitable www interface
• keen scientific interest in survey exploitation
  (Andy Taylor, Dan Burkey, Andy Lawrence)
• PhD student (started Oct 2000)

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Data and information flow in the 6DFGRS
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