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Q. Taylor (Penn State University), F. Heitsch, R. Indebetouw (U of Wisconsin-Madison)
Molecular clouds are the birthplaces of stars. Turbulence in the interstellar medium (ISM) is a main ingredient of star formation theory. Its effects inlude pressure support of otherwise gravitationally instable regions, promotion of gravitational collapse due to density enhancements in shocks, and mixing of chemical species. Observationally, turbulence manifests itself in broadened spectral line width and self-similar density structures, resulting in power-law-like power spectra.
The GLIMPSE survey will provide unprecedented high-resolution data of the diffuse emission in the molecular ISM at four far-infrared wavelengths, containing information about the medium's density structure in various evolutionary states. Applying 2-point correlation functions (power spectra and structure functions) to 2MASS and MSX data of the Orion and M17 star formation regions, we investigate whether this information can be extracted from maps of diffuse emission.
Removing the point sources from the maps allows us to extract spectra with clear power-law behavior. The slopes steepen with absolute intensity. Interpretation is complicated by the highly complex interaction of radiation and density structure in the molecular ISM. We discuss the limitations of the method and possible improvements. This work was supported by a NSF-REU site grant (AST-0139563) to U of Wisconsin-Madison.
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.