THEMIS data handling

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THEMIS data handling

• Arturo López Ariste
• Alberto Sainz Dalda

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THEMIS MTR mode
MTR Multiline spectropolarimetry mode
Up to 10 spectral domains observed simultaneously
from 4000 Å through 13000 Å Full freedom on
scanning over the solar surface and on
polarimetric modulation cycle 1 Gbyte /hour
data rate.
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Some bad experiences

• On the telescope
• Observers cannot handle the raw data flow.
• Up to 75 of the observers are not at hands with
  raw spectropolarimetry data
• More than 50 of the observers come to THEMIS to
  measure the magnetic field and not Stokes
  parameters.

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Some bad experiences

• On the telescope
• Observers cannot handle the raw data flow.
• Up to 75 of the observers are not at hands with
  raw spectropolarimetry data
• More than 50 of the observers come to THEMIS to
  measure the magnetic field and not Stokes
  parameters.

• At BASS 2000
• Users are not interested in raw data
• Users are not interested on Stokes parameters
• Users want magnetic field maps
• Users are not used to vector fields!

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What we did/are doing

• Online data reduction code SQUV
• Quasi-automatic , quasireal-time
• Provides Stokes parameters from raw data
• Handles all normal situations (above 80 success
  rate)
• Ensures a nominal 10-3 polarimetric sensitivity.
• Provides up to 10-4 at shared-risk policy

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What we did/are doing

• Online data reduction code SQUV
• It is automatically launched by the telescope at
  the end of appropriate observing sequences
• Can be downloaded for personal use under GNU-like
  license (www.themis.iac.es)
• It is being implemented at BASS2000 for old data.

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Example
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What we did/are doing

• Stokes analysis and inversion
• GUI-tools to check profiles and build maps
• GUI-tools to invert (Fe I 630 nm line,
  Milne-Eddington)
• GUI-tools to check inversions
• GUI-tools to to analyze vector fields in
  observers and local frames and investigate
  azimuth ambiguity

Online at the telescope, inversion launched by
the acquisition system Downloadable under
GNU-like license (www.themis.iac.es)
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PCA Inversion
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Some bad experiences

• On the telescope
• Observers cannot handle the raw data flow.
• Up to 75 of the observers are not at hands with
  raw spectropolarimetry data
• More than 50 of the observers come to THEMIS to
  measure the magnetic field and not Stokes
  parameters.

• At BASS 2000
• Users are not interested in raw data
• Users are not interested on Stokes parameters
• Users want magnetic field maps
• Users are not used to vector fields!

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