Measuring H2 spin temperature in molecular cloud by near-infrared absorption spectroscopy
Final Report Abstract
The goal of the present proposal was to measure the nuclear-spin temperature, i.e., the population ratio of ortho- and para-molecular hydrogen, in cold dark clouds. We wanted to show it is not in equilibrium with the kinetic temperature of the clouds, as the theories have predicted for long time. The preparatory works were done in time with the start of the project and were incrementally updated and brushed up during the project period. The upgraded high-resolution spectrograph of the VLT, CRIRES+, was integral rig for the observations. As the delays of the return of CRIRES+ to the telescope were announced, we modified our workflows, but trying to keep the nuclear spin of H2 as the central piece of the project. Fortunately, new infrared spectrographs (other than CRIRES+) came online during the funding period - iSHELL at the IRTF, EXES onboard SOFIA, 3KK at Wendelstein, and the prospect of NIRSpec on the JWST. We spent quite busy three years, utilizing these new observational resources, for investigating interstellar ice, deuterium chemistry, and quantitative measurement of dust extinction in dark clouds.
Publications
- "The first frost in the Pipe Nebula", Astronomy and Astrophysics, 610, 9, (2018)
Goto, Miwa, Bailey, Jeffrey D., Hocuk, Seyit, Caselli, Paola, Esplugues, Gisela B., Cazaux, Stephanie, and Spaans, Marco
(See online at https://doi.org/10.1051/0004-6361/201629830) - "Search for H3+ isotopologues toward CRL 2136 IRS 1", Astronomy and Astrophysics, 632, 29 (2019)
Goto, Miwa, Geballe, T. R. Harju, Jorma S., Caselli, P., Sipilä, O., Menten, K. M., Usuda, T.
(See online at https://doi.org/10.1051/0004-6361/201936119)
