Ion–Molecule Reactions as a Possible Synthetic Route for the Formation of Prebiotic Molecules in Space

International audienceThanks to many astrophysical observations, the number of prebiotic molecules observed in space is growing daily. Organic molecules, which can be the first building blocks for appearance of life, were found in both interstellar medium and comets. As an example, several molecules with the peptide bond moiety were reported, like formamide and urea. The glycine detection has a long and controversial history, and it was recently reported on the comet 67P/Churyumov-Gerasimenko. A general question concerns how these molecules could be formed given the extreme conditions of space. Theoretical chemistry, combined in some cases with laboratory experiments, can help in quantifying the physical chemistry conditions which can allow their synthesis. Here, we summarize some studies on the particular case of ion-molecule collisions

The use of aerosol data in Auger Fluorescence Detector analysis

The Pierre Auger Observatory's Fluorescence Detector (FD) consists of 27 telescopes arranged in four sites around the perimeter of the 3000 square kilometre Surface Detector (SD). Cosmic ray extensive air showers are viewed via the nitrogen fluorescence light they induce in the atmosphere. Careful treatment of light attenuation processes must be made, especially given that some showers are viewed at distances in excess of 30 km. Of particular importance is the attenuation due to scattering by aerosol particles, a challenging topic given that aerosol concentrations can vary on time-scales of hours. At the Auger Observatory, the vertical distribution of aerosols is measured hourly with a series of bi-static lidar systems (consisting of central laser facilities and each of the FD sites), and three times per night with a Raman lidar system. In this contribution we describe the use of aerosol profiles in the analysis of air shower data, in particular in the estimation of the cosmic ray primary energy, and the depth of shower maximum, X-max. We also demonstrate how statistical and systematic uncertainties in the aerosol concentrations propagate through to a contribution to energy and X-max uncertainties