New views of star birth and the heart of a spiral galaxy have been seen by
a state-of-the-art astronomical instrument on its first night. The new
UKIRT Imaging Spectrometer (UIST) has a revolutionary ability to ‘slice’
any object in the sky into sections, producing a three dimensional view of
the conditions throughout entire galaxies in a single observation. UIST
has just been installed on the United Kingdom Infrared Telescope (UKIRT)
in Hawaii.

Project scientist Suzanne Ramsay Howat from the UK Astronomy Technology
Centre (ATC) in Edinburgh said “UIST will give astronomers using UKIRT a
unique way of viewing the Universe, keeping this telescope at the
cutting-edge of science”.

The instrument saw its ‘First Light’ on the night of 24th September, when
it was trained on the Omega Nebula. This nebula, also called Messier 17,
is a gas cloud where new stars are forming. Located 5000 light years from
Earth, M17 is a near neighbor and can be studied in exquisite detail with
an instrument such as UIST. The intense ultraviolet radiation from young,
hot stars blasts the atoms in clouds of interstellar gas, making them glow
brightly as seen in the bottom right of the UIST image.

One of the most exciting new features of UIST is its ‘image slicer’ or
Integral Field Unit (IFU). The IFU ‘slices’ the light from an astronomical
target into thin sections. Each slice is then spread out to make a
spectrum, rather like the rainbows produced when light passes through a
prism of glass. Astronomers can use these spectra to investigate the
interactions between stars, cosmic dust and gas in complex objects like
galaxies.

The image slicer was tested in UIST’s first night on UKIRT. The galaxy
NGC1068, 47 million light years from Earth, was chosen for the
observations. This galaxy is known to have an active nucleus, or centre,
which is a perfect target for the image slicer. The IFU creates an
infrared ‘data cube’ from the galaxy’s nucleus in a single observation.
This can be sliced in one direction to show the appearance of the nucleus
at a single infrared wavelength, or at right angles to produce spectra
across the entire nucleus.

The UIST team have spent five weeks commissioning and installing the
instrument on UKIRT. The telescope is situated atop Mauna Kea on the Big
Island of Hawaii, which is one of the best sites in the world for
astronomy. This follows five years of construction at the ATC in
Edinburgh, where the team overcame many technological challenges.

Dr Ramsay Howat explained “At infrared wavelengths, the ambient heat of
the instrument itself creates unwanted background light. To avoid this,
the entire 750kg instrument is cooled inside a cryostat to about -200C,
just 70 degrees above absolute zero. The dinner plate sized wheels that
allow different optical components to be selected have to be rotated to
within 1/250 of a degree, and the optical pathways must stay precisely
aligned even as the instrument shrinks in the extreme cold.”

At the heart of UIST is an extremely sensitive infrared detector with a
million pixels – 16 times more than the previous spectrometer ‘CGS4’. UIST
combines and improves upon the capabilities of the instruments previously
on the telescope.

Dr Andy Adamson, Director of UKIRT, is extremely excited about the future
with UIST. “Combining the power of UIST imaging and spectroscopy with the
telescope’s excellent image quality will revolutionise observations at
UKIRT. We’ll be able to image objects of interest and analyse them
spectrally, all with the same instrument.”

Images

See http://outreach.jach.hawaii.edu/pressroom/2002_uist/ for larger
versions.

“UIST infrared image of the Omega Nebula, a site of star formation 5000
light years from Earth.” Image: Joint Astronomy Centre.
http://outreach.jach.hawaii.edu/pressroom/2002_uist/m17.jpg

“The active galaxy NGC1068, imaged using the Integral Field Unit, or
‘image slicer’. The greyscale image in the foreground shows the galactic
nucleus in combined infrared light. Above is an image slice at a single
wavelength, and to the right is a spectral slice showing the spectra
across the entire nucleus.” Image: Stephen Todd, ROE and Douglas
Pierce-Price, JAC.
http://outreach.jach.hawaii.edu/pressroom/2002_uist/ifu.jpg

“The UK Infrared Telescope (UKIRT), on Mauna Kea, Hawaii – UIST’s new
home.” Photograph: Royal Observatory, Edinburgh.
http://outreach.jach.hawaii.edu/pressroom/2002_uist/ukirt.jpg

“UIST arrives at UKIRT.” Photograph: Mel Strachan, UK ATC.
http://outreach.jach.hawaii.edu/pressroom/2002_uist/arrival.jpg

Notes to Editors

UIST:

The UKIRT Imaging Spectrometer (UIST) was designed and built at the UK
Astronomy Technology Centre (UK ATC) in Edinburgh. It detects infrared
light with wavelengths between 1 and 5 microns with a 1024 x 1024 pixel
Indium Antimonide detector array. It can be used for imaging,
spectroscopy, integral field spectroscopy, and polarimetry. These multiple
abilities allow it to replace almost all the existing instrumentation on
UKIRT. It has the first “common-user” infrared integral field unit
available to the astronomical research community. It cost just under UKP
3M to build and was funded by the Particle Physics and Astronomy Research
Council (PPARC). It will enable astronomers to take advantage of the
better image quality that resulted from the UKIRT Image Upgrades Programme
that was completed in 1998.

The Omega Nebula (Messier 17):

This nebula is a gas cloud which is a site of vigorous star formation. It
is located in our own galaxy at a distance of 5000 light years from Earth.
The intense ultraviolet radiation from young, hot stars blasts the atoms
in clouds of interstellar gas. The clouds glow brightly, as seen in blue
in the bottom right of the UIST image. At some distance from the new
stars, the starlight stops destroying the cloud. This is marked by the
sharp transition from light to dark running diagonally across the picture.
Behind this line, astronomers can study the original gas cloud, seeking to
understand the process of stellar birth.

NGC1068:

NGC1068 is a ‘Seyfert 2’ galaxy located 47 million light years from Earth.
It has an active galactic nucleus surrounded by a ring, or torus, of
molecular gas.

UKIRT:

The world’s largest telescope dedicated solely to infrared astronomy, the
3.8-metre UK Infrared Telescope (UKIRT) is sited near the summit of Mauna
Kea, Hawaii, at an altitude of 4194 meters above sea level. It is operated
by the Joint Astronomy Centre in Hilo, Hawaii, on behalf of the UK
Particle Physics and Astronomy Research Council.

The UK ATC:

The UK Astronomy Technology Centre is located at the Royal Observatory,
Edinburgh (ROE). It is a scientific site belonging to the Particle Physics
and Astronomy Research Council (PPARC). The mission of the UK ATC is to
support the mission and strategic aims of PPARC and to help keep the UK at
the forefront of world astronomy by providing a UK focus for the design,
production and promotion of state of the art astronomical technology.

The ROE:

The Royal Observatory, Edinburgh comprises the UK Astronomy Technology
Centre (UK ATC) of the Particle Physics and Astronomy Research Council
(PPARC), the Institute for Astronomy (IfA) of the University of Edinburgh
and the ROE Visitor Centre.

Contacts

* Douglas Pierce-Price
Science Outreach Specialist, Joint Astronomy Centre
Email: outreach@jach.hawaii.edu
Tel: +1 808 969 6524
Fax: +1 808 961 6516

* Eleanor Geer
PR Officer, Royal Observatory Edinburgh
Email: efg@roe.ac.uk
Tel: +44 131 668 8397

* Dr. Suzanne Ramsay Howat
UIST Project Scientist
Email: s.ramsay-howat@jach.hawaii.edu
Tel: +1 808 969 6512 (until December 2002)

* Dr. Sandy Leggett
UIST Imaging Instrument Scientist, Joint Astronomy Centre
Email: s.leggett@jach.hawaii.edu
Tel: +1 808 969 6523

* Dr. Chris Davis
UIST Spectroscopy Instrument Scientist, Joint Astronomy Centre
Email: c.davis@jach.hawaii.edu
Tel: +1 808 969 6520

Web links

JAC UIST press release and information
http://outreach.jach.hawaii.edu/pressroom/2002_uist/

About UKIRT
http://outreach.jach.hawaii.edu/articles/aboutukirt/

JAC UIST home page
http://www.jach.hawaii.edu/JACpublic/UKIRT/instruments/uist/uist.html

ATC UIST home page
http://www.roe.ac.uk/atc/projects/uist/index.html

JAC outreach home page
http://outreach.jach.hawaii.edu/

PPARC home page
http://www.pparc.ac.uk/