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Kira Edler, 617-358-1240
For Release: March 23, 2006
NEW MAP OF MILKY WAY CHARTS WHERE STARS ARE BORN
Boston University scientists produce clearest images of star-forming clouds
Boston -- A team of astronomers from Boston University's Institute for
Astrophysical Research has produced the clearest map to-date of the
giant gas clouds in the Milky Way that serve as the birthplaces of
stars. Using a powerful telescope, the astronomers tracked emissions of
a rare form of carbon monoxide called 13CO to chart a portion of our
home galaxy and its star-forming molecular clouds.
The researchers hope the new illustration will aid in the identification
of additional clouds and study of their internal structure to better
understand the origin of stars like the sun, which began its life in
such a cloud about 5 billion years ago. The data and images are
published in the March issue of the Astrophysical Journal Supplement.
The eight-year project, called the Boston University-Five College Radio
Astronomy Observatory (FCRAO) Galactic Ring Survey (GRS), was led by a
team of astronomers based at BU, the University of Cologne in Germany,
and the University of Massachusetts.
To produce the detailed image, the astronomers mapped the location of
13CO in the Milky Way using a large radio telescope operated by the
FCRAO of the University of Massachusetts that captures and images radio
emissions at a frequency near 100,000 MHz -- about 1,000 times higher
than FM stations. When viewed in the emission from 13CO, the clouds are
far more transparent than the more traditionally studied 12CO which
allowed the team to peer more deeply into their interior.
"The value of such high range imaging is that it enables us to identify
the underlying patterns of gas distribution and speeds that point toward
the key physical processes occurring within the molecular gas phase of
the interstellar medium," said Dr. Mark Heyer, a researcher from UMass
involved in the project.
Using a new receiver developed at UMass, the astronomers could depict
the structure of the clouds faster and with much finer detail than any
previous attempts. As an added benefit, the distribution of the clouds
also delineates the spiral structure of the Milky Way.
"Ironically, because we live inside the Milky Way, we know more about
the shapes of far more distant galaxies better than our own," said James
Jackson, astronomy professor at BU and lead investigator of the study.
"The GRS map helps us better understand the configuration of our home
galaxy and its components."
"Upon seeing the GRS image, I knew right away it was something terrific.
It was like the first time I put on glasses as a kid, and wondered how I
ever got along without knowing about every shape, contour and detail of
the world around me," said Dr. Ronak Shah, a researcher from BU who
worked on the project. "The GRS has that affect on a lot of us. We
thought we understood the Milky Way and then the GRS revealed so much
more detail to explore."
According to Dr. Robert Simon, now at the University of Cologne, but who
started the project with Jackson in 1998 at BU, the information from the
GRS will constitute an important new database for the study of molecular
clouds and Milky Way structure for generations of astronomers.
The scientists are now closely analyzing the image and one of the
initial findings is the probable identification of dark, cold molecular
clouds in the earliest stages of star development.
"Data from the Galactic Ring Survey have shown that these clouds are the
counterparts to active, bright star-forming clouds, but because they
have not yet been heated by the embedded stars, they are much colder and
quieter," said Jackson. "Follow-up studies of these clouds will provide
additional important clues about the origin of stars since we'll be able
to examine them at an earlier point in their life."
Another interesting result is that all of the molecular clouds studied
so far have similar lumpy structures, regardless of their size, mass,
and star-forming activity. These lumps will eventually become stars and,
according to the researchers, this similarity suggests that all clouds
form stars of various masses in roughly the same proportion.
The Milky Way is a vast disk of 100 billion stars, gas, and dust and
because it is flat, the map is long and narrow. Since most of the Galaxy
lies in the Southern skies, unreachable from Northern Hemisphere
telescopes, and because many of the molecular gas clouds are
concentrated toward its inner regions, only a portion was imaged.
The Institute for Astrophysical Research (IAR) was founded in 1998 in
order to promote and facilitate research and education in astrophysics
at Boston University. The IAR supports research by BU Astronomy faculty
members, graduate and undergraduate students, and postdoctoral and
senior research associates. In addition, the IAR manages and coordinates
the use of astrophysical research facilities and promotes the design,
development, and operation of instruments and telescopes for
Founded in 1839, Boston University is an internationally recognized
institution of higher education and research. With more than 30,000
students, it is the fourth largest independent university in the United
States. BU contains 17 colleges and schools along with a number of
multi-disciplinary centers and institutes which are central to the
school's research and teaching mission.
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Note to editors: Images available at