The VIMOS IFU Pipeline Carlo Izzo

The VIMOS IFU

The VIMOS IFU LR mode HR and MR mode

The VIMOS IFU

Flat fields

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.

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.

vmifucalib _________________________________

vmifucalib

vmifuscience

vmifucalib Extracted scientific spectra Reconstructed FOV image

Spectral extraction (pixel)

Fiber profile

Fiber profile HR blue HR red (pixel)

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

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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