arXiv subjects
Publications and source records attributed to F. Eisenhauer.
In this paper, we discuss the benefits of ground-based, adaptive optics (AO) aided observations for star formation research. After outlining the general advantages, we present results obtained during the ALFA science demonstration programme in 1999. These results underline the absolute necessity of AO assistance for almost any kind of observations regarding star formation regions.
SINFONI, the SINgle Faint Object Near-infrared Investigation, is an instrument for the Very Large Telescope (VLT), which will start its operation mid 2002 and allow for the first time near infrared (NIR) integral field spectroscopy at the diffraction limit of an 8-m telescope. SINFONI is the combination of two state-of-the art instruments, the integral field spectrometer SPIFFI, built by the Max-Planck-Institut fuer extraterrestrische Physik (MPE), and the adaptive optics (AO) system MACAO, built by the European Southern Observatory (ESO). It will allow a unique type of observations by delivering simultaneously high spatial resolution (pixel sizes 0.025arcsec to 0.25arcsec) and a moderate spectral resolution (R~2000 to R~4500), where the higher spectral resolution mode will allow for software OH suppression. This opens new prospects for astronomy.
We present SPIFFI, the integral field spectrometer for the VLT. This instrument allows simultaneous observation of infrared spectra in more than 1000 image points of a two dimensional field. With its set of four gratings and a pixel scale that can be varied by a factor of ten, SPIFFI provides high flexibility, and at the same time offers the unique possibility of diffraction limited imaging spectroscopy at an 8m-class telescope, when fed by the adaptive optics system MACAO. We outline the scientific drivers for building such an instrument, the concept of image slicing, the optical design, and the implementation of SPIFFI.
Integral-field-spectroscopy and multi-object-spectroscopy provide the high multiplex gain required for efficient use of the upcoming generation of extremely large telescopes. We present instrument developments and designs for both concepts, and how these designs can be applied to cryogenic near-infrared instrumentation. Specifically, the fiber-based concept stands out the possibility to expand it to any number of image points, and its modularity predestines it to become the new concept for multi-field-spectroscopy. Which of the three concepts --- integral-field-, multi-object-, or multi-field-spectroscopy --- is best suited for the largest telescopes is discussed considering the size of the objects and their density on the sky.
We have observed NGC 3603, the most massive visible HII region known in the Galaxy, with ANTU(VLT1)/ISAAC in the near-infrared (NIR) J_s, H, and K_s bands. Our observations are the most sensitive observations made to date of this dense starburst region, allowing us to investigate with unprecedented quality its low-mass stellar population. Our mass limit to stars detected in all three bands is 0.1 Mo for a pre-main sequence star of age 0.7 Myr. The overall age of the pre-main sequence stars in the core region of NGC 3603 has been derived from isochrone fitting in the colour-magnitude diagram, leading to 0.3 - 1.0 Myr. The NIR luminosity functions show that the cluster is populated in low-mass stars at least down to 0.1 Mo. Our observations clearly show that sub-solar mass stars do form in massive starbursts.