IFS SURVEY OF THE ORION NEBULA: DATA RELEASE

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 ~3700-7100Å, FWHM~1.6 Å), 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.

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.