|Measuring the CO-H2 ratio in warm gas
|The CO-H2 ratio is commonly used in numerous astrophysical systems to determine the total amount of molecular hydrogen from observations of CO. However, our current knowledge of this fundamental quantity is mostly based on measurements of cold gas; for the case of hot gas we rely only on a couple of direct measurements, dating back to almost 20 years ago. Here we propose to measure the CO-H2 ratio and its possible variations in hot gas. Our aim is to combine observations from Herschel and Spitzer tracing both molecules, in regions excited by protostelalr outflows. Current investigations show that emission from CO and H2 arises from gas at very similar excitation conditions. This fact provides strong indications that both molecules trace the same volume of gas, and therefore comparison of their column densities can directly lead to their ratio.
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2013, OT2_odionato_3, SPG v14.2.0. https://doi.org/10.5270/esa-p6j3rvu