INTEGRAL FIELD SPECTROSCOPY AT THE VLT STAR (CLUSTER) FORMATION IN 3D : INTEGRAL FIELD SPECTROSCOPY AT THE VLT Markus Kissler-Patig (Instrument Scientist for VIMOS and SINFONI) European Southern Observatory, Garching, Germany VIMOS and SINFONI VIMOS IFU Our program (PI: N.Bastian, Utrecht) aims at studying the star forming complexes in merging galaxies selected along the Toomre sequence. The Observations were obtained in Service Mode with the Integral-Field Unit (IFU) of VIMOS on the VLT. The IFU allows one to obtain 1600 spectra simultaneously in spectral resolution mode, paving an area on the sky of ~30”x30”, with a resolution of 0.67”. We have used here the ‘high-resolution’ (R~2500) blue grism covering the range Å. The following images show a preview of our results for one of the NGC 4038/4039 pointings obtained so far. Data for NGC 7252 have also been analyzed and will be published soon. Several instruments attached to the ESO VLT offer integral field spectroscopy as an observing mode. Not only has this mode become much easier to use than in the past, but both pipelines for data reduction as well as visualization tools are becoming available, making the reduction and analysis as easy as for more classical modes such as imaging and long-slit spectroscopy. VIMOS is available since one year at the VLT, although the pipeline for IFU data only became public recently. Its main characteristic: Wavelength range: nm Spectral Resolution: Field of View: 15”x15” - 60”x60” Spatial resolution: 0.33”/spaxel or 0.67”/spaxel Number of spaxels: 40x40 or 80x80 The region of the spectrum around the'blue bump’ Wolf-Rayet [4650 A] feature for the five complexes in field 1. The continuum has been subtracted from each spectrum. The WR feature is clearly observed in complexes 4 and 5, and weakly, though definitely present, in complex 1. Observed spectra of the cluster complexes in Field 1. All spectra are in the rest wavelength of NGC 4038, and have not been corrected for extinction. Prominent emission lines are indicated, including the Wolf-Rayet feature at ~4650 Å. The spectra have been binned using a boxcar function with width 4.5 Å. HST images in B (top) and B,V,H  (bottom) Reconstructed VIMOS IFU data cube, each spatial element (spaxel) of 0.67”x0.67” on the sky has an associated spectrum of 2048 pixel ( 0.5Å/pix). The integration time was ~2h in the HR_blue set-up. SINFONI The Science Verification (SV) for SINFONI consists of a number of programs aimed at giving a preview of the instrument capabilities. One program (coordinated by L.Tacconi- Garman, ESO Garching) aims at studying a couple of star clusters in the starburst galaxies NGC 253 and NGC A very first preview is given on the left. The first test data have been obtained 2 weeks ago with the H+K grating and the largest field of view. The program foresees to obtain data using the adaptive optics (AO) capability of SINFONI and closing the loop on the brightest star cluster (R~15 mag) to then make full use of the 12.5x25mas/spaxel plate-scale. Under very good atmospheric conditions, SINFONI can use AO guide star as faint as R~17 mag to improve the image quality. All data (raw and reduced) for this and the other SV programs will be made public within 2 months of the observations through the ESO web pages. SINFONI is offered now for P75 (deadline Oct 1, 2004 for observation starting April 1, 2005). Its main characteristic: Adaptive Optics assisted (optional, not mandatory!) Wavelength range: nm Spectral Resolution: Field of View: 0.8”x0.8” or 3”x3” or 8”x8” Spatial resolution: 12.5x25mas/spaxel or 50x100mas/spaxel or 125x250mas/spaxel Number of spaxels: 64x32 “Finding chart” (HST image at 0.95 microns) for the two young star clusters in NGC 253. Below, the data are viewed with the Euro3D visualization tool (coded by S.Sanchez, IAP, Potsdam). This tool allows to view both the raw data, the reconstructed image (in any wavelength range) and the extract spectrum of selected spaxels. Its many analysis tool make it a powerful tool also for fast analysis. The two star clusters were observed with SINFONI in the H+K band (covering 1.4 to 2.5 microns) at a resolution of 125x250mas/spaxel, (8”x8” field-of-view) for 6x200s. The data were reduced by the pipeline routines and the data cubes are shown with two freely available visualization tools. The data are displayed here with QfitsView (coded by T.Ott, MPE, Garching). The tool is well suited for fast viewing of the data. Br  in emission (2.17  m) testifies of the young star cluster.