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Scientists are announcing today the discovery of a "cosmic chimney" extending upwards from the spiral disk of our Milky Way Galaxy. The chimney, shown in the accompanying picture, was discovered in a new study of the ecosystem of the galaxy by an international consortium of scientists. The picture shows a region of sky 18 times the diameter of the full moon from left to right, as it would appear if our eyes were sensitive to radio radiation. The large, dark cone-shaped feature (apex near center of picture) is a hollow cavity (chimney) surrounded by bright glowing neutral hydrogen gas. (Two dark spots just to the right of center are artifacts of the image processing.) The chimney is about 250 light years across at the top and the entire feature is approximately 6,500 light years away in a neighbouring spiral arm (see accompanying diagram).
At the bottom of the chimney is a star cluster containing hot massive stars which are formed, live their lives and then die in spectacular supernova explosions all within several million years, a relatively short time by astronomical standards. The discovery of this chimney over a region of massive star formation is significant because it lends support to theories suggesting that the hot blast of many supernova explosions can create large vertical cavities through the galactic spiral disk.
Inside the chimney are many smoke-like filaments, including a bright "V" which looks like rabbit ears and is observed to be moving upwards. At the apex of the V lies a smaller denser cloud (diagram), suggesting that dense cloud material may have been blown off into the V shape by the hot supernova wind as it flows up the chimney like exhaust. The exhaust contains heavier elements which pollute the galactic atmosphere above and may eventually rain back down at other places on the galactic disk. It is not yet known whether the fire of many supernovae is raging now or whether we are observing wisps of smoke from the cinders of explosions which took place many millions of years ago. Further observations are being planned to help solve this mystery. Recent evidence suggests that the sun and our solar system may also exist within a cavity similar to this one.
The image was obtained by Magdalen Normandeau, a graduate student at the University of Calgary, as part of a pilot project to map the entire observable Milky Way using a radio telescope at the Dominion Radio Astrophysical Observatory near Penticton, B. C. The international consortium, led by Dr. Russ Taylor of the University of Calgary, consists of 34 members from North American and European Institutes and Universities. The study is expected to take over 3 years to complete. These early results are being presented by Normandeau, Taylor and Dewdney at the meeting of the Canadian Astronomical Society at the Coast Lakeside Resort (PH: (604) 493-8221), May 28 - 31 in Penticton, B. C. The image, this text, and diagram may be obtained via anonymous ftp to astro.queensu.ca in the directory pub/press. A black and white image is stored in chimneybw.(extension) and a colour image is in chimneycol.(extension) where (extension) indicates the file type (e.g. postscript, tiff, or gif). The diagram is in diagram.(extension) and text in newsrelease.text. The package can also be accessed via the world wide web at http://astro.queensu.ca/~irwin/press.html
Contacts:
Russ Taylor, University of Calgary Principal Investigator (403) 220-5385 or (604) 493-2277 (May 24-June 1) russ@bear.ras.ucalgary.ca
Peter Dewdney, Dominion Radio Astrophysical Observatory (604) 490-4322, or (604) 493-2277 ped@drao.nrc.ca
Neb Duric, University of New Mexico (505) 277-5238 duric@deneb.unm.edu
Carl Heiles, University of California, Berkeley (510) 642-4510 heiles@bkyast.berkeley.ca
Judith Irwin, Queen's University (613) 545-2717 (602) 299-2020 (28 May - 5 June) irwin@astro.queensu.ca
Gilles Joncas, Laval University (418) 656-2652 joncas@phy.ulaval.ca
Peter Martin, University of Toronto and Canadian Institute for Theoretical Astrophysics (416) 978-6840 pgmartin@cita.utoronto.ca
Bill McCutcheon, University of British Columbia (currently at Joint Astronomy Center, Hilo) (604) 822-6234 whm@jach.hawaii.edu
David Routledge, University of Alberta (403) 492-5668 david_routledge@mts.ucs.ualberta.ca
