Other
Scientific paper
Dec 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997hst..prop.7175b&link_type=abstract
HST Proposal ID #7175
Other
Hst Proposal Id #7175 Interstellar Matter
Scientific paper
Molecular hydrogen {H_2} emits strong near-infrared line emission, both in regions where it is thermally excited at high temperatures {T>1000 K, e.g. in molecular shocks}, and in the illuminated boundaries of molecular clouds {photon-dominated regions or PDRs} where it is excited by UV pumping. In the case of UV fluorescence, when the illuminating radiation is fairly uniform, observed fluctuations in the H_2 line intensity will trace fluctuations in density and column density in the boundary layer of the molecular cloud. Narrow-band imaging at high angular resolution in H_2 lines with HST/NICMOS, will probe the small-scale structure of PDRs, which is intimately related to the interstellar turbulence. We propose a series of images in the F212N {H_2 1-0 S1} and F215N {adjacent continuum} filters of the entire nebula IC 63. The pure, strong emission allows the medium-band filters F171M and F180M to probe different combinations of H_2 lines. This comparison will also help to calibrate better the reflected light. The Orion Bar feature southeast of the Trapezium is a well studied PDR with some very interesting chemical and physical features {Hogerheijde, Jansen, and van Dishoeck 1995; Jansen 1995}. We propose a series of H_2 images across the bright rim of the bar. A particular position angle is chosen so that parallel exposures with the other NICMOS cameras will probe other tracers at other positions on the bar.
No associations
LandOfFree
H2 imaging of photon-dominated regions {PDRs} does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with H2 imaging of photon-dominated regions {PDRs}, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and H2 imaging of photon-dominated regions {PDRs} will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-895173