here - Institute for Astronomy Umleitung

Title: Science Case
Reference: MUSE-MEM-SCI-052
Issue: 1.3
Date: 04/02/2004
Page: 99/100
parameters, which are generally not easy to quantify, such as the accuracy of sky subtraction,
PSF stability, minimization of diffuse light, etc. However, optimizing such key aspects of the
instrument performance forms the very basis upon which MUSE has been designed and shall
be built, and we are confident that this will ultimately ensure the achievement of our aims.
8.3. High spatial resolution IFU
In contrast to wide-field IFUs, which are not numerous, there is a growing number of AOassisted
IFUs in development or in operation. In the following table we show the main
competitors (operating or planned) for 8m telescopes.
Instrument GNIRS+IFU NIFS OSIRIS SINFONI MUSE
Telescope Gemini S Gemini N Keck VLT VLT
Multiplex type Slicer IFU Slicer IFU Lenslet IFU Slicer IFU Slicer IFU
No. spatial elements 620 2000 1000 1000 90,000
Spatial sampling,
arcsec/pixel
0.07x0.07 0.04x0.10 0.02
0.05
0.10
FOV (arcsec) 2.2x1.5 3.0x2.9 1.28x0.32
3.20x0.80
6.40x1.60
0.025
0.10
0.25
0.8x0.8
3.2x3.2
8x8
0.025
7.5x7.5
Spectral elements 1000 2000 1300 2000 4000
Spectral resolutions 1800, 6000 5300 3800 4000 3000
Wavelength range 0.9-2.5 µm 0.9-2.5 µm 1-2.5 µm 1-2.5 µm 0.46-0.93 µm
Detector 1kx1k InSb 2k x 2k
HgCdTe
2k x 2k 2k x 2k 24x4kx4k
CCD
Date comm. 2003 (NS) 2005 2004 2004 2011
Table 8-2: Existing or planned AO assisted IFU on 8m class telescopes
In the following we have focused our comparison with SINFONI which is available at VLT,
but most of what will follow is also be valid for the other instruments. We limit our
comparison to the 25 milli-arcsec sampling of SINFONI.
One can then perform the same computation as in previous subsection. This gives a gain of 90
in Etendue 10 and 135 in 3D power for MUSE with respect to SINFONI. But the key
parameter is the spatial resolution given by the AO system. It is well known that AO
performance is much better in the infrared than in the optical. The SINFONI predicted
performances are quite good, with 50% Strehl ratio in the K band. However, this performance
is obtained only with a bright, natural on-axis guide star (V