The VIMOS IFU PipelineThe VIMOS IFU Pipeline

Carlo IzzoCarlo Izzo

The VIMOS IFUThe VIMOS IFU

The VIMOS IFUThe VIMOS IFU

HR and MR modeHR and MR modeLR modeLR mode

The VIMOS IFUThe VIMOS IFU

Flat fieldsFlat fields

IFU pipeline - historical backgroundIFU pipeline - historical background

• The IFU pipeline was delivered by the VIRMOS Consortium on June The IFU pipeline was delivered by the VIRMOS Consortium on June 2003. No documentation was available, and only LR spectral 2003. No documentation was available, and only LR spectral observations were supported at the time. The IFU DRS was also observations were supported at the time. The IFU DRS was also declared not to be suitable for declared not to be suitable for automaticautomatic data reduction. data reduction.

• On July 2003 it was decided to rewrite the IFU pipeline from On July 2003 it was decided to rewrite the IFU pipeline from scratch. Valuable suggestions about IFU data reduction issues were scratch. Valuable suggestions about IFU data reduction issues were provided by Eric Emsellem and Arlette Rousset-Pecontal (provided by Eric Emsellem and Arlette Rousset-Pecontal (Centre de Centre de Recherche Astronomique de LyonRecherche Astronomique de Lyon), and by Martin Roth (), and by Martin Roth (Astro-Astro-physikalisches Institut Potsdamphysikalisches Institut Potsdam).).

• The new ESO VIMOS pipeline, based on the CPL, was designed and The new ESO VIMOS pipeline, based on the CPL, was designed and developed in about eight months. It was delivered to Paranal on developed in about eight months. It was delivered to Paranal on March 2004, and to the user community on July 2004.March 2004, and to the user community on July 2004.

VIMOS IFU pipeline recipesVIMOS IFU pipeline recipesvmifucalib:vmifucalib:

• Input: a sequence of flat field and one arc lamp exposures.Input: a sequence of flat field and one arc lamp exposures.

• Produces the extraction mask (spectral tracing + wavelength Produces the extraction mask (spectral tracing + wavelength calibration), and the relative transmission correction.calibration), and the relative transmission correction.

vmifuscience:vmifuscience:

• Input: scientific exposure, extraction mask, and relative Input: scientific exposure, extraction mask, and relative transmission correction. Optionally, a spectral response curve.transmission correction. Optionally, a spectral response curve.

• Produces the extracted, wavelength calibrated, transmission Produces the extracted, wavelength calibrated, transmission corrected spectra, and a reconstructed image of the field-of-view. corrected spectra, and a reconstructed image of the field-of-view. Optionally, a relative flux correction can be applied.Optionally, a relative flux correction can be applied.

vmifustandard:vmifustandard:

• Analogous to Analogous to vmifusciencevmifuscience, it produces also a spectral response , it produces also a spectral response curve.curve.

vmifucalibvmifucalib

__________________________________________________________________

vmifucalibvmifucalib

vmifusciencevmifuscience

vmifucalibvmifucalib

Extracted scientific spectra

Reconstructed FOV image

Spectral extractionSpectral extraction

(pixel)

(pixel)

Fiber profileFiber profile

HR redHR blue

Fiber profileFiber profile

(pixel)

ProblemsProblems

• Instrument instability ruins the scientific reduction online, and Instrument instability ruins the scientific reduction online, and enforces the acquisition of night calibrationsenforces the acquisition of night calibrations

• Contamination between multiplexed spectra may occasionally Contamination between multiplexed spectra may occasionally prevent an accurate tracing and a correct fiber identificationprevent an accurate tracing and a correct fiber identification

• The extraction mask cannot be aligned to a “dark” scientific The extraction mask cannot be aligned to a “dark” scientific exposureexposure

It would be nice…It would be nice…

• WCS on reconstructed images of the field-of-viewWCS on reconstructed images of the field-of-view

• Alignment and sum of jittered exposuresAlignment and sum of jittered exposures

• Optimal extractionOptimal extraction

• More interactivityMore interactivity