Infrared Space Observatory Measurements of [C II] Line Variations in Galaxies

摘要: We report measurements of the [C II] fine-structure line at 157.714 ?m in 30 normal star-forming galaxies with Long Wavelength Spectrometer (LWS) on Infrared Space Observatory (ISO). The ratio to total far-infrared (FIR) luminosity, LC II/LFIR, measures cooling gas that dust, and thus efficiency grain photoelectric heating process. This varies by more than a factor 40 current sample. About two-thirds have II/LFIR ratios narrow range (2-7) ? 10 -->?3. other one-third show trends decreasing increasing dust temperature, as measured flux infrared emission 60 100 ?m, F?(60 ?m)/F?(100 ?m), star formation activity, FIR blue-band LFIR/L -->B. also find three FIR-bright are deficient line, which is undetected 3 upper limits ?4. trend temperature activity may be due decreased high UV radiation intensity grains become positively charged, yield energy photoelectrons. no observed photodissociation region lines among highest -->B ?m) ratios. Their lack continuing seen sample warm IRAS colors. In case, imply density G -->0/n>10 cm -->3 (where -->0 units local average interstellar field). low could either weak II], owing self-absorption, or strong continuum from regions such dense H II plasma ionized hard active galactic nuclei. mid-infrared radio images these most comes compact nucleus. CO I detected galaxies, absorption toward