South Pole Telescope Uncovers Organic
Molecules in the Bear's Paw Nebula!
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Media Release - School
of Physics - The University of New South Wales
Tuesday May 23, 2000 |
Using a new infrared telescope at the
South Pole, astronomers at the University of New South Wales have
studied the star forming region NGC 6334, more commonly known by
its popular name the "Bear's Paw Nebula". They found it to
be enveloped by an extensive cloud of gas rich in organic molecules.
These are seen through the infrared emission from of "polycyclic
aromatic hydrocarbons" (or PAHs), commonly found on the Earth in
the waste products of biological species or in auto-exhaust!
The images taken at the South Pole are
amongst the first ever obtained with a new infra-red telescope (called
SPIREX, or 'South Pole Infrared Explorer'). This 60-cm telescope
exploits the extremely cold, dry and stable conditions at the South
Pole to take more sensitive images in the infra-red than can be
obtained anywhere else on the Earth. SPIREX has been developed by
the UNSW astronomers in conjunction with colleagues from the USA.
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Image
Left : Three colour optical emission image of NGC
6334, courtesy of David Malin (Anglo Australian Observatory),
taken with the 3.9-m Anglo-Australian Telescope.
The red glow, somewhat reminiscent of a bears paw, comes
from hot hydrogen gas fluoresced by the intense ultraviolet
radiation from the young stars. The green box
marks the area observed in the infrared.
copyright, David Malin, Anglo Australian
Observatory
Image Right
: Infra-red emission from the heart of NGC 6334,
as imaged by the 60-cm SPIREX Telescope at the South
Pole. The blue shows the emission from polycyclic
aromatic hydrocarbons (PAHs) at 3.3µm, the green
shows continuum emission at 3.5µm and the (faint)
red colour shows hydrogen emission at 4.1µm.
This is the widest-field and most sensitive image
ever taken at these wavelengths with this spatial
resolution.
Image by Michael Merrill, copyright
UNSW/CARA
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Not only do the images taken with SPIREX
reveal extensive emission from PAHs, they reveal the ionized gas
at the heart of the cloud and the massive, young stars they surround.
Shells of UV-fluoresced molecules, 3-5 light years across, surround
bubbles of ionized gas, 0.5-1 light years in size, around sites
of star formation. Massive protostars are found at the centre
of the bubbles. The SPIREX images show these stars to be at
different stages of their birth process. All these stars are
invisible in the optical image.
SPIREX is a prototype telescope and
was designed to show that sensitive astronomical observations were
possible from the Antarctic plateau, despite the harsh environment.
Its success has shown that the conditions are superb for wide-field
imaging at thermal infrared wavelengths, where the "heat" from the
Earth's atmosphere makes observations particularly difficult.
At these wavelengths astronomers can study the birth of stars and
galaxies, within dense cocoons of gas and dust that hide them from
view at optical wavelengths. Despite its modest size (and cost)
the SPIREX Telescope obtained the most sensitive wide-field images
ever taken at these wavelengths at high angular resolution.
This research program has as its goal
the construction a 2-metre size telescope in Antarctica, capable
of being the most sensitive on the Earth for the measurement of
the faint infrared light from protostars and protogalaxies.
It could be built for a fraction of the cost of space facilities,
and yet still be capable of complementing the programs planned for
the largest telescopes in the world. It would provide Australia
with a front-line facility for the 21st century.
A paper with more details on these results
has been accepted by the Astrophysical Journal, and can be obtained
from this
web site (note that it is compressed (gzip format) postscript
file 7 Mbytes in size). Entitled 'High resolution imaging
of photodissociation regions in NGC 6334', it is authored by Michael
Burton, Michael Ashley, Rodney Marks, Antony Schinckel and John
Storey from UNSW, Al Fowler, Mike Merrill and Nigel Sharp from the
National Optical Astronomy Observatory in the USA, Ian Gatley from
the Rochester Institute of Technology, Al Harper, Bob Loewenstein
and Fred Mrozek from the Yerkes Observatory of the University of
Chicago and Jim Jackson and Kathleen Kraemer from Boston University.
The data presented in this paper was
obtained by
Rodney Marks while wintering at the South Pole during 1998.
Tragically, Rodney died of natural causes on May 12, 2000 while
again wintering over at the Pole, working on another astronomical
project. Rodney's perseverance and dedication, overcoming
considerable difficulties through the Antarctic winter, was crucial
to to this program's success. Rodney's pioneering efforts
have shown that infrared astronomy in Antarctica can be a reality,
not just a dream. This paper is dedicated to Rodney's memory.
Further information on the Antarctic
astronomy program at UNSW can be obtained from the UNSW
Astrophysics home page. Live images from the South Pole can
be viewed from the webcam
(though until sunrise in September it is dark), attached to the
AASTO
(Automated Astrophysical Site Testing Observatory).
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