The VIMOS IFU Pipeline

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The VIMOS IFU Pipeline

• Carlo Izzo

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The VIMOS IFU
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The VIMOS IFU
HR and MR mode
LR mode
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The VIMOS IFU
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Flat fields
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IFU pipeline - historical background

• The IFU pipeline was delivered by the VIRMOS
  Consortium on June 2003. No documentation was
  available, and only LR spectral observations were
  supported at the time. The IFU DRS was also
  declared not to be suitable for automatic data
  reduction.
• On July 2003 it was decided to rewrite the IFU
  pipeline from scratch. Valuable suggestions about
  IFU data reduction issues were provided by Eric
  Emsellem and Arlette Rousset-Pecontal (Centre de
  Recherche Astronomique de Lyon), and by Martin
  Roth (Astro-physikalisches Institut Potsdam).
• The new ESO VIMOS pipeline, based on the CPL, was
  designed and developed in about eight months. It
  was delivered to Paranal on March 2004, and to
  the user community on July 2004.

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VIMOS IFU pipeline recipes

• vmifucalib
• Input a sequence of flat field and one arc lamp
  exposures.
• Produces the extraction mask (spectral tracing
  wavelength calibration), and the relative
  transmission correction.
• vmifuscience
• Input scientific exposure, extraction mask, and
  relative transmission correction. Optionally, a
  spectral response curve.
• Produces the extracted, wavelength calibrated,
  transmission corrected spectra, and a
  reconstructed image of the field-of-view.
  Optionally, a relative flux correction can be
  applied.
• vmifustandard
• Analogous to vmifuscience, it produces also a
  spectral response curve.

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vmifucalib
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vmifucalib
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vmifuscience
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vmifucalib
Extracted scientific spectra
Reconstructed FOV image
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Spectral extraction
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Fiber profile
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Fiber profile
(pixel)
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Problems

• Instrument instability ruins the scientific
  reduction online, and enforces the acquisition of
  night calibrations
• Contamination between multiplexed spectra may
  occasionally prevent an accurate tracing and a
  correct fiber identification
• The extraction mask cannot be aligned to a dark
  scientific exposure

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It would be nice

• WCS on reconstructed images of the field-of-view
• Alignment and sum of jittered exposures
• Optimal extraction
• More interactivity

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THE END