S.F.Sánchez (CAHA), M.Verheijen (Kapteyn Inst.), N.Cardiel (UCM), D.Martin-Gordon (IAA), J.M.Vilchez (IAA), J.Alves (CAHA)

The Orion IFS survery was performed as a legacy project of PPAK (PI: M.Verheijen), the wide-field mode of PMAS, mounted at the 3.5m telescope on Calar Alto. In total comprises just 1.5h of observations during an useless night for the main project (Mass Disk Project). We release the reduced dataset freely to the comunity for its public use with the only condition of citing the data relase article (at the bottom of this webpage), and the to acknowledge the Calar Alto observatory with the usual acknoledgement.

Fig 1:The 31 individual Mosaic Pointings of PPAK, comprising each one 331 individual spectra. Only 27 were used in the final datarelease. OBSERVATION AND DATA REDUCTION

Observations were carried out the night of the 21st of November 2004, using the PMAS spectrograph (Roth et al. 2001) in the PPAK mode (Kelz et al. 2006), at the 3.5m telescope at the Calar Alto Observatory. PPAK is a wide-field Integral Field Unit, consisting of 331 science fibers packed in an hexagonal bundle of 72"X64" field-of-view, with a filling factor of ~65%. In order to test the capabilities of the instrument for Mosaicing, and covering of large areas, we dedicated a low-transparency/bad seeing night to obtain low-resolution spectroscopy of the largest possible area of the ORION nebulae. The nights were allocated to Dr.M.Verheijen, who was directly involved in the development of PPAK, and very well willing to perform this test in an otherwise useless night.

We obtained 31 mosaic pointings of 2s exposure time on the central regions of the ORION nebulae with PPAK using the V300 grating (range ~3700-7100, FWHM~1.6 ), and covering a total area of ~5'X6' (~30 arcmin2). To our knowledge this is the largest area ever covered with an IFU in a contiguous way. The data, comprising ~10000 individual spectra, are in the process of being reduced using R3D (a package for reducing IFS data also developed at Calar Alto), and they will be freely distributed for the community, once the reduction and calibration processes has been finished (as a "legacy" of the PPAK project).

Figure 1 illustrates the observing strategy of the Mosaic, starting from the very center of the Nebulae, and following and spiral pattern. Each individual pointing overlaps in one of the edge of the PPAK bundle hexagon with the next one, to ensure enough overlapping for creating the Mosaic.

An example of the restored emission line maps:

Fig 3:Three color image created using the reconstructed line intensity map of Hα, [OIII]5007, Hβ, obtained by the fitting procedure described in the article. The final sampling of the maps was 1"/pixel.

The ORION Integrated spectrum

Fig 4:Integrated spectrum obtained by coadding all the spectra in the dataset.

Lines identified in the integrated spectrum

  • Line Identification (Strong Lines)
  • Line Identification (Faint Lines)
  • Line Identification (Faint Lines)
  • Line Identification (Faint Lines)



  • "Integral Field Spectroscopy survey of the Orion Nebula. Data Release."S.F. Sanchez, N.Cardiel, M.A.W.Verheijen,
    D.Martin-Gordon, J.M.Vilchez, J.Alves, AA accepted (astro-ph/0611363)