Wednesday 27 Sep 2017Laboratory high resolution spectroscopy and novel spectrometers for astrophysical diagnostics

Dr. Damien Weidmann - STFC Rutherford Appleton Laboratory

Physics, 4th Floor 14:00-15:00

Spectroscopy is the tool of choice to carry out remote characterization of the physics and chemistry beyond the Earth. Being from the ground using large telescopes, or from orbit using space-borne observatories, spectrometers are used to gather emission and/or absorption spectra of a wide range of radiating objects in space. Planetary atmospheres (recently including exoplanets), stars, galaxies, and interstellar medium can thus be characterised and better understood.
From spectra, a wealth of quantitative thermo-physical information can be derived on distant molecules and atoms, providing reference data exist to carry out the relevant modelling and interpretation. These reference data include molecular (or atomic) transition frequencies, intensities, temperature dependence, and pressure (collisional) dependence. In the first part of the seminar, the High-Resolution Spectroscopy Facility, operated by the Spectroscopy Group of RAL Space will be presented. This facility has been extensively used to generate reference spectroscopic data for the Earth atmosphere as well as planetary atmospheres from the solar system, and offers opportunities for laboratory spectroscopy serving the astrophysics community.
The second part of the seminar will expose the concept of thermal infrared laser heterodyne spectro-radiometry, that allows spectral analysis at very high resolving power (>500,000), combined to high angular resolution. Development of the technique for Earth observation and opportunities for extension to planetary and astrophysics applications will be presented.

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