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Published October 1, 2006 | Published
Journal Article Open

The Bubbling Galactic Disk

Abstract

A visual examination of the images from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) has revealed 322 partial and closed rings that we propose represent partially or fully enclosed three-dimensional bubbles. We argue that the bubbles are primarily formed by hot young stars in massive star formation regions. We have found an average of about 1.5 bubbles per square degree. About 25% of the bubbles coincide with known radio H II regions, and about 13% enclose known star clusters. It appears that B4-B9 stars (too cool to produce detectable radio H II regions) probably produce about three-quarters of the bubbles in our sample, and the remainder are produced by young O-B3 stars that produce detectable radio H II regions. Some of the bubbles may be the outer edges of H II regions where PAH spectral features are excited and may not be dynamically formed by stellar winds. Only three of the bubbles are identified as known SNRs. No bubbles coincide with known planetary nebulae or W-R stars in the GLIMPSE survey area. The bubbles are small. The distribution of angular diameters peaks between 1' and 3' with over 98% having angular diameters less than 10' and 88% less than 4'. Almost 90% have shell thicknesses between 0.2 and 0.4 of their outer radii. Bubble shell thickness increases approximately linearly with shell radius. The eccentricities are rather large, peaking between 0.6 and 0.7; about 65% have eccentricities between 0.55 and 0.85.

Additional Information

© 2006 American Astronomical Society. Received 2005 November 14; accepted 2006 June 9. We thank Stephan Jansen, who has been tireless in keeping our computers online. We also acknowledge the IRAC instrument team, who delivered such a superb instrument to Spitzer, and the staff of the Spitzer Science Center, who have been very supportive of the GLIMPSE program. We thank the anonymous referee, whose incisive comments led to the substantial improvement of this work. This research made use of Montage, funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computational Technologies Project, under Cooperative Agreement NCC5-626 between NASA and the California Institute of Technology. Support for this work, part of the Spitzer Space Telescope Legacy Science Program, was provided by NASA through contracts 1224653 (University of Wisconsin at Madison), 1225025 (Boston University), 1224681 (University of Maryland), 1224988 (Space Science Institute), 1242593 (University of California at Berkeley), 1253153 (University of Minnesota), 11253604 (University of Wyoming), and 1256801 (University of Wisconsin at Whitewater) by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Facilities: Spitzer(IRAC)

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023