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A new instrument installed
on the Very Large Telescope (VLT) at the European Southern Observatory
(ESO) in Chili will provide scientists with detailed information for the
study of the physical properties of a number of galaxies that form in
the distant Universe. This new spectrograph, known as FLAMES/GIRAFFE,
was developed through collaborative work by the European Southern Observatory,
the Observatoire de Paris, the Observatoire de Genève, and the
Anglo Australian Observatory. The instrument has 15 Integral Field Units
(IFUs), each one made up of a mosaic of 20 optical fibers that can be
positioned on an area of the sky. Each IFU looks like an insect's eye;
together they record no less than 300 spectra simultaneously. The fiber
optics systems and the spectrograph were developed by the GEPI Laboratory
of the Observatoire de Paris.
Within the next few months at the ESO, one of the VLT's four telescopes
measuring 8.2 meters in diameter (Kueyen) will be equipped with a new
spectrograph called FLAMES/GIRAFFE. The spectrograph is connected to a
system of 15 fiber bundles known as Integral Field Units (IFUs). Each
unit consists of a mosaic of 20 microlenses (a microlens measures 0.3
x 0.3 mm), which are connected to 20 optical fibers. These IFUs are positioned
in the focal plane by a fiber positioner. The entire system guides light
to the spectrograph.
Working under the ESO's responsibility and with its support, the GEPI
Laboratory of the Observatoire de Paris (a joint CNRS/third party laboratory)
developed the IFU fiber systems and the Giraffe spectrograph. The Anglo
Australian Observatory built the fiber positioner and the Observatoire
de Genève worked with the GEPI to develop the data reduction software.
With the 15 IFUs making simultaneous observations, there will be a spectacular
increase in the volume of astrophysical data about distant objects, enabling
astronomers to study, in greater detail, the physical properties of galaxies
as they are being formed.
These observations will lead to a better understanding of the velocity
fields of a wide range of galaxies in the distant Universe, when it was
only one third to one half its current age, providing detailed information
about the internal structure and motions of the gas clouds within these
celestial objects. Such research is essential to gain a better understanding
of galaxies and, in particular, the way in which, through successive fusions,
they are formed and contribute to building the Universe.
For more information:
Observatoire de Paris:
: http://www.obspm.fr/actual/nouvelle/jan02/flames.shtml
ESO: http://www.eso.org/outreach/press-rel/pr-2002/pr-01-02.html
Research contacts:
François Hammer
Observatoire de Paris
Tel: +33 1 45 07 74 08.
E-mail: francois.hammer@obspm.fr
Véronique CAYATTE
Observatoire de Paris
Tel: +33 1 45 07 74 24.
E-mail: veronique.cayatte@obspm.fr
CNRS-INSU (National Institute for Sciences of the Universe) contact :
Philippe Chauvin
Tel: +33 1 44 96 43 36
E-mail: Philippe.Chauvin@cnrs-dir.fr
Observatoire press contact:
Christiane Adam
Tel: +33 1 45 07 74 74
E-mail: christiane.adam@obspm.fr
Press contact :
Martine Hasler
Tel : +33 1 44 96 46 35
e-mail : martine.hasler@cnrs-dir.fr
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