Astronomical instrumentation

Abstract:

The mid-infrared instruments, operating in the 10 and 20 mum atmospheric windows, on the Gemini 8-m telescopes are described. The advantages and disadvantages of ground-based telescopes compared to satellite observatories are briefly discussed. On Gemini-N, Michelle, a cryogenic imager and grating and echelle spectrometer built at the UK Astronomy Technology Centre in Edinburgh offers imaging, long-slit spectroscopy and polarimetry. Spectral resolving powers between 200 and 20,000 are available by selecting one of five interchangeable gratings held in the cold grating drum. The Thermal Region Camera-Spectrometer (TReCS) is undergoing final tests at the University of Florida before delivery to Gemini-S. It offers imaging and low or moderate resolving power (R < 1000) spectroscopy. Even with the excellent image quality and low-emissivity of the Gemini telescopes, the thermal background from the sky, telescope and instrument windows are many orders of magnitude greater than the mid-infrared background emission in space. The main advantages of the Gemini instruments are the high spatial resolution available from large aperture ground-based telescopes (FWHM similar to lambda/D = 0.3 arcsec at 12 mum), the versatile instrumentation and the high spectral resolution, which coupled with the 50 m(2) collecting area, gives good spectroscopic performance. Some initial performance figures and results are given. (C) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Abstract:

In this paper we describe two coating and fabrication techniques we have developed applicable to astronomical instrumentation with particular emphasis on the FMOS instrument for the Subaru telescope.

Abstract:

We present a summary of high-spatial resolution follow-up observations of the elliptical (E) and lenticular (SO) galaxies in the SAURON survey using the OASIS integral field spectrograph. The OASIS observations explore the central 8" x 10" regions of these galaxies using a spatial sampling four times higher than SAURON, often revealing previously undiscovered features. Around 75% (31/48) of the SAURON E/SOs with central velocity dispersion greater than or similar to 120 kin s(-1) were observed with OASIS, covering well the original SAURON representative sample. We present here an overview of this follow-up survey, and some preliminary results on individual objects, including a previously unreported counter-rotating core in NGC4382; the decoupled stellar and gas velocity fields of NGC 2768; and the strong age gradient towards the centre of NGC 3489.

Abstract:

SPIFFI (SPectrometer for Infrared Faint Field Imaging) is a fully cryogenic, near-infrared imaging spectrograph built at the Max-Planck-Institute for Extraterrestrial Physics (MPE) and upgraded with a new detector and spectrograph camera by ASTRON/NOVA, ESO and MPE. The upgraded instrument will become a facility instrument for the ESO VLT in summer 2004 as part of the SINFONI (SINgle Faint Object Near-IR Investigation) project, which is the combination of SPIFFI and ESOs adaptive optics module MACAO (Multiple Application Curvature Adaptive Optics), at the Cassegrain focus of Yepun (UT4). In spring 2003 we had the opportunity to observe with SPIFFI as a guest instrument without the AO-module at the Cassegrain focus of UT2 of the VLT. In this paper we discuss the performance of SPIFFI during the guest-instrument phase. First we summarize the technical performance of SPIFFI like the spatial and spectral resolution, the detector performance and the instruments throughput. Afterwards we illustrate the power of integral field spectroscopy by presenting data and results of the Galactic Center.