|The Australia Telescope National Facility Colloquium|
|11:00-12:00 Fri 21 Apr 2006|
ATNF Marsfield Lecture Theatre
Dr Martin Cohen
(University of California, Berkley, USA)
Multiwavelength studies in the Galactic Plane with MSX and Spitzer - Dr Martin Cohen Colloquium
The power of multiwavelength combinations of radio and optical data with infrared imagery from space can be applied to analyses of several different aspects of the interstellar medium along the Galactic Plane. The intimate association of photodissociation regions with HII regions implies the existence of a quantitative relationship between integrated fluxes of ionized domains in the mid-infrared and radio continuum. The ratio of 8.3-micron MSX flux to Molonglo 843-MHz continuum flux is a valuable tool that discriminates between thermal and nonthermal emission processes. These correlations are explored in a new study of HII regions using both MSX and the Spitzer GLIMPSE Legacy survey. Direct comparison of Spitzer 8.0-micron fluxes with MSX 8.3-micron fluxes for HII regions clearly reveals a problem with the diffuse calibration of IRAC. HII regions provide independent quantitative evidence for the discrepancy at 8.0 microns. However, IRAC imagery provides a unique perspective on the structure of HII regions and enables a search to be made for weakly ionized haloes of compact regions, akin to those suggested at radio wavelengths.
This loads a font easier to read for people with dyslexia.
This renders the document in high contrast mode.
This renders the document as white on black
This can help those with trouble processing rapid screen movements.