Huge Images Show Majestic Beauty and Violence of Large and SmallMagellanic Clouds (Forwarded)

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EMBARGOED FOR RELEASE: 9:20 a.m. EST, Monday, January 9, 2006

RELEASE NO: NOAO 06-01

Huge Images Show Majestic Beauty and Violence of Large and Small
Magellanic Clouds

The glowing gas of the interstellar medium (ISM) is the breeding ground
for the formation of new stars, and the cemetery where the ashes of dead
stars ultimately return.

A team led by astronomers from the National Optical Astronomy Observatory
(NOAO) has conducted a new study called the Magellanic Cloud Emission Line
Survey (MCELS) that focused expressly on the ISM in the Large Magellanic
Cloud and Small Magellanic Cloud -- the nearest major galaxies to the
Milky Way.

Hundreds of individual images from MCELS have been assembled into large
mosaics of each nearby galaxy being released to the public in Washington,
DC, at the annual meeting of the American Astronomical Society, in
anticipation of presentations today and on Wednesday, January 11.

"Extinction of light from dust hides most of our own galaxy from view at
optical wavelengths, and it is often difficult to determine distances
accurately. For these reasons, we must look beyond the Milky Way to gain a
global perspective on the interstellar medium," said NOAO astronomer Chris
Smith, principal investigator for MCELS. "The Magellanic Clouds provide a
unique venue for studying the interstellar medium and its components on
all size scales."

The Large and Small Magellanic Clouds are neighboring patches of glowing
starlight readily visible in Earth's southern skies. They are named after
Ferdinand Magellan, the Portuguese explorer who, along with other members
of his 1519 expedition, were the first Europeans to sight these objects.
The Large and Small Clouds are now recognized as the closest major
galaxies, at distances of about 160,000 and 200,000 light-years,
respectively.

MCELS data are revealing a wealth of new information about structures in
the Magellanic Clouds: glowing clouds of gas that surround hot, newly
formed stars; small planetary nebulae barely a light-year across; much
larger shell-like remnants of stars that died as supernovae; and, giant
super-shell complexes carved out by multiple supernovae, stretching
thousands of light-years.

"MCELS reveals interstellar gas that has been heated and energized by
stars, and so it's an especially valuable data set for understanding how
energy and matter cycle between stars and gas," said MCELS team member
Sally Oey of the University of Michigan, Ann Arbor. "This is important to
us since we, and the entire Earth, are made up of material that has been
cycled through ancient stars and interstellar gas."

The MCELS team surveyed both galaxies using the University of Michigan's
0.9-meter Curtis Schmidt telescope at the National Science Foundation's
Cerro Tololo Inter-American Observatory near La Serena, Chile. Five
wavelength bands were used: emission lines of hydrogen (H-alpha),
doubly-ionized oxygen ([O III]), and singly-ionized sulfur ([S II]), plus
red and green continuum bands.

Carried out over five years, the survey covered the central 8 by 8 degrees
of the LMC, and 3.5 by 4 degrees of the SMC, regions that include most of
the gas found in both galaxies. The SMC mosaic image comprises over 500
individual images, while over 1,500 have been combined for the LMC mosaic.

In general, the team conducts its research by using the continuum images
to subtract most of the stars from the images. "This technique reveals far
fainter and more extensive gaseous emission," said team member Frank
Winkler of Middlebury College, Middlebury, VT, who led the assembly of the
SMC image. "In fact, we can observe gaseous structures 20 times fainter
than the night sky."

"In conjunction with surveys of the Magellanic Clouds carried out at other
wavelengths, MCELS will lead to a fuller understanding of processes that
shape the interstellar medium, and mark the beginnings and ends of stellar
lives," said team member Sean Points of NOAO.

MCELS is also an example of the significant science that can be done by
undergraduate students. Students at the University of La Serena, Chile,
and at Middlebury College have played key roles in all phases of the
survey, from the original observations to processing the data to assembly
of the mosaic images presented at the AAS meeting. Analyses based on the
survey have led to four bachelor's degree honors theses at Middlebury and
one at La Serena.

For more information on MCELS and these results, see poster 25.07 today,
and special session 145 and poster session 132 on Wednesday. The new
mosaic images of the LMC and SMC are on display in large format at the
NOAO exhibit booth (# 500) at the AAS meeting. Digital image files are
available in a variety of resolutions at
http://www.noao.edu/outreach/press/p...01.html#images

The MCELS project has been supported in part by NSF grants AST-9540747 and
AST-0307613, and through the generous support of the Dean B. McLaughlin
Fund at the University of Michigan. The National Optical Astronomy
Observatory is operated by the Association of Universities for Research in
Astronomy Inc. (AURA), under a cooperative agreement with the National
Science Foundation.

IMAGE CAPTIONS;

[Image 1:
http://www.noao.edu/image_gallery/html/im0993.html]
More than 500 individual images from MCELS have been assembled into this
large mosaic of the Small Magellanic Cloud, released to the public in
Washington, DC, in January 2006 at the annual meeting of the American
Astronomical Society.

Credit: F. Winkler/Middlebury College, the MCELS Team, and NOAO/AURA/NSF

[Image 2:
http://www.noao.edu/image_gallery/html/im0994.html]
More than 1,500 individual images from MCELS have been assembled into this
large mosaic of the Large Magellanic Cloud, released to the public in
Washington, DC, in January 2006 at the annual meeting of the American
Astronomical Society.

Credit: C. Smith, S. Points, the MCELS Team and NOAO/AURA/NSF