Matthias Tecza

Abstract:

We present the results of our subarcsecond resolution interferometric observations of the 1.3 mm CO J = 2-->1 line in the luminous merger NGC 6240. Roughly half of the CO flux is contained in a rotating and highly turbulent thick disk centered between the two radio and near-infrared nuclei. In this disk the molecular gas has velocity widths which reach FWZP line widths of up to 1000 km s(-1). The mass of this gas concentration makes up between 30%-70% of the dynamical mass in this region. NGC 6240 may be in an earlier merging stage than typical ULIRGs such as Arp 220. We compare these results from NGC 6240 with those of other luminous, gas-rich interacting galaxies and mergers.

Abstract:

SINFONI, the SINgle Faint Object Near-infrared Investigation, is an instrument for the Very Large Telescope (VLT), designed to provide spectroscopy at the telescope diffraction limit in the near-infrared. This unique capability is achieved by combining two state-of-the-art developments, an integral field spectrometer (SPIFFI) and a curvature sensor based adaptive optics system (MACAO). SINFONI is a collaborative effort by the Max-Planck-Institut fur extraterrestrische Physik (MPE) and the European Southern Observatory (ESO).SINFONI will operate at the Cassegrain focus of Unit Telescope 1 (UT1) of the VLT, in conjunction with a Laser Guide Star (LGS) for almost complete sky coverage. It will provide integral field data cubes, with a hexagonal field of view ranging from similar to 1 " to 8 ", with corresponding pixel sizes of 0." 03 to 0." 25. The field of view contains 1024 spatial pixels, with similar to 100% filling factor in the focal plane. Spectra are obtained for each of the 1024 pixels. Spectral resolutions of R=2000 to R=4500 will be available, covering the J, H and K spectral windows. The high spectral resolution made will allow software OH suppression in the J and H bands. The detector is a 1024(2) HgCdTe HAWAII array from Rockwell. Spectroscopy of faint objects (m(K) < 21 and m(H) < 22) will be easily feasible.

Abstract:

The SINFONI1 project combines the MPE cryogenic near-infrared imaging spectrometer SPIFFI2 with an ESO adaptive-optics system on the ESO-VLT to perform high spatial and spectral resolution studies of compact objects. This paper describes the optical design of SPIFFI and the novel techniques used in building its integral-field unit.The image slicer comprises of a bundle of 1024 silica/silica fibers, where each fiber tip is flared to increase the core diameter by a factor of 15. The tapered end is polished to form a spherical microlens with a hexagonal cross-section to couple Light into the optical fiber. This not only yields a high light-coupling efficiency and a high geometrical filling factor but also allows us to use the fiber bundle at a working temperature of 77 K without losing positioning accuracy.

Abstract:

SPIFFI (SPectrometer for Infrared Fibre-fed Field Imaging) is an integral field spectrograph with an HAWAII array that enables us to simultaneously take near infrared spectra of 1024 spatial pixels in an hexagonal field of view on the sky. It can be used on 4 to 8 meter class telescopes with a maximum pixel scale of 0.5 arcsec and with adaptive optics pixel scales, Nyquist sampling the point spread function of the telescope.A fiber bundle of 1024 silica/silica fibers rearranges the two-dimensional field of view into the one-dimensional entrance slit of the spectrometer. A novel technique involving flared fibers is used to achieve a high filling factor and coupling efficiency. Each fiber tip in the bundle is flared to increase the fiber core diameter by a factor of 15. The tapered end is polished to form a spherical micro-lens with a hexagonal cross-section to couple light into the fiber core. Apart from yielding a high coupling efficiency and a high geometrical filling factor, the monolithic micro-lens/fiber system can be used at a working temperature of 77 K without loosing positioning accuracy.The spectrometer optics is achromatic from 1.1 to 2.5 microns and uses four reflection gratings on a wheel as dispersing elements with a resolving power from 2000 to 4500. The fore-optics includes the filter wheel, the cold pupil stop and a scale changing mechanism to switch between three different image scales according to observing and seeing conditions. The spectrometer collimator is a f/4.3 three lens achromat, the spectrometer camera is a f/1.2 folded Schmidt camera. The optical design of the spectrometer is distortion free to get straight, equidistant spectra that match the columns of the detector, thus minimizing cross-talk from adjacent spectra to less than 5%.

Abstract:

We present new near-infrared speckle and adaptive optics imaging and integral field spectroscopy of the nuclear region of NGC 1068. Ninety-four percent of the K-band light in the central 1" originates from a ≤30 milliarcsecond diameter source whose position we determine to coincide within ± 0''15 with the apex of the cone structure seen in the optical narrow emission lines, as well as the location of the flat spectrum radio component SI and the 12 μm emission peak. We interpret the compact source as hot dust near the sublimation temperature within ∼ 1 pc of the true nucleus of the galaxy. The remaining 6% of the light in the central 1″ comes from a moderately extincted stellar core centered on the nuclear position and of intrinsic size ∼50 pc. We show that this nuclear stellar core is probably 5-16 × 108 yr in age and contributes at least 7% of the total nuclear luminosity of ~1 × 1011 L⊙. © 1997. The American Astronomical Society. All rights reserved.