Effects of Extinction on Broad Band Spectra of HII Regions

Session 108 - HII Regions.
Display session, Thursday, January 18
North Banquet Hall, Convention Center

[108.02] Effects of Extinction on Broad Band Spectra of HII Regions

G. J. Ferland (Kentucky), R. H. Rubin (NASA/Ames), P. G. Martin (Toronto), R. J. Dufour, C. R. O'Dell, Z. Wen (Rice), J. A. Baldwin (CTIO), J. J. Hester (Arizona State), D. K. Walter (S.Carolina State)

Many HII Regions are illuminated blisters flowing off the face of a background molecular cloud. The observed spectrum is a combination of radiation which escapes from the HII region in the direction towards the observer, and a second spectrum reflected from the molecular cloud. The reflection efficiency of the molecular cloud ranges from a low near zero in the far infrared, where the effective grain albedo is near zero, to a high near 30% at ultraviolet wavelengths. Consideration of this reflection component is very important when observations over a broad wavelength range are considered. We outline a method where the presence of this reflection component can be directly taken into account when de-reddening broad band observations.

Supported by AURA/STScI grants related to GO-4385 amp; GO-6056.

Program listing for Thursday