SPIFFI: A high-resolution near-infrared imaging spectrometer
P SOC PHOTO-OPT INS 3354 (1998) 394-403
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%.The nuclear stellar core, the hot dust source, and the location of the nucleus of NGC 1068
Astrophysical Journal 490:1 PART I (1997) 238-246
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.3D - A new generation imaging spectrometer
P SOC PHOTO-OPT INS 2871 (1997) 1179-1186
Abstract:
3D is a new type of a highly sensitive near-infrared integral field spectrometer developed at MPE. It has been designed to multiplex spectral as well as spatial information thus obtaining a full data cube in a single integration. At a spectral resolution between 1000 and 2000 and a field of view of 16 x 16 pixels, optimized for subarcsecond spatial resolution imaging spectroscopy, it has a much higher efficiency compared to conventional techniques. Outfitting one of the VLTs with a near-IR 3D type instrument will provide a powerful tool for diffraction-limited integral field spectroscopic research, in particular on faint high-z galaxies in the early universe. The basic design, recent upgrades as well as plans for a possible VLT-3D instrument are presented.NIR imaging spectroscopy of IRAS F10214+4724: Evidence for a starburst region around an AGN at z=2.3
REV MEX AST ASTR 6 (1997) 48-51
Abstract:
We report 1'' K-band imaging spectroscopy of the z=2.284 galaxy IRAS F10214+4724. We find that the rest-frame H alpha and [N II] emission have different spatial extents. Furthermore, we detect broad (Delta upsilon(FWZP)approximate to 3500 km s(-1)) H alpha emission. We conclude that F10214+4724 is a very luminous gravitationally lensed galaxy, which intrinsically contains both a type 1 AGN and a more extended star-forming disk. The AGN and circumnuclear star formation both contribute significantly to the total luminosity of similar to 10(13)L(circle dot).The nuclear stellar cluster in NGC 1068
ASTROPHYS SPACE SCI 248:1-2 (1997) 225-234