Astronomical instrumentation

Abstract:

LUCIFER (LBT NIR-Spectroscopic Utility with Camera and Integral-Field Unit for Extragalactic Research) is a NIR spectrograph and imager for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona. It is built by a consortium of five German institutes and will be one of the first light instruments for the LBT. Later, a second copy for the second mirror of the telescope will follow. Both instruments will be mounted at the bent Gregorian foci of the two individual telescope mirrors. The final design of the instrument is presently in progress.LUCIFER will work at cryogenic temperature in the wavelength range from 0.9 mum to 2.5 mum. It is equipped with three exchangeable cameras for imaging and spectroscopy: two of them are optimized for seeing-limited conditions, the third camera for the diffraction-limited case with the LBT adaptive secondary mirror working. The spectral resolution will allow for OH suppression. Up to 33 exchangeable masks will be available for longslit and multi-object spectroscopy (MOS) over the full field of view (FOV). The detector will be a Rockwell HAWAII-2 HgCdTe-array.

Abstract:

Encouraged by imaging of faint galaxies around bright stars using ALFA on the 3.5-m telescope at Calar Alto, we have begun a survey to identify a large number of candidate sources near bright stars. In this contribution we report the status of this survey and show our preliminary results from deep imaging around one of these stars during the early phases of CONICA and NAOS on the 8.2-m VLT. We outline the exciting prospects for this type of work in terms of number counts, morphology, and rotation curve analyses.

Abstract:

Red spectra of a sample of low-mass stars and brown dwarfs in the Orion Trapezium cluster are discussed. They show late-type spectral characteristics confirming cluster membership and some show evidence of circumstellar activity.

Abstract:

We present very deep JHK imaging of the Trapezium Cluster obtained with Gemini South/Flamingos and Gemini North/Hokupa'a. These images probe the IMF down to similar to 2 M-Jup in a total area of similar to 8 arcmin(2). Several very faint new planetary mass candidates are detected and sources previously detected with UKIRT are verified. Photometry of 124 point sources in this field produces a Luminosity Function which. drops to zero at K=18.75. Allowing. for modest extinction this corresponds to a possible turn-down in the IMF near 5 Mjup. A minority of PMOs exhibit large K band excesses attributed to hot dust, confirming their extreme youth. Some of the faintest sources are associated with short trails of light of uncertain nature. These may provide a clue to the origin of PMOs, perhaps marking evacuated paths cleared by rapidly moving objects.