AHUIR, M. Jérémy (2017) Towards the cosmological evolution of the Cold Gas Mass Density PFE - Project Graduation, ENSTA.
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Abstract
The apparent divergence in the evolution of the star formation rate and the hydrogen mass density bodes a significant role of molecular hydrogen in the process of consumption of gas for stellar formation. However, the lack of observations is at the origin of uncertainties on the dynamics of molecular hydrogen synthesis and star formation. In the light of the low densities involved in the interstellar and intergalactic media, the study of H2 absorption lines in quasar spectra constitutes an interesting option. To avoid systematic bias due to a HI selection, a blind search in quasar spectra is required. For challenging spectra, such as those from the UVES sample, a preliminary study has been performed, comprising emission lines recognition, a power-law fit of the continuum and gaps correction. A probabilistic approach to detect H2 absorbers, by imposing a constraint on the implemented synthetic spectra, allows a successful redshift detection and a good fit of the Voigt profile, leading to a satisfying estimate of column densities. Then, an estimate of the quality of the search is performed in a first attempt to establish an automated distribution function of H2 absorbers.
Item Type: | Thesis (PFE - Project Graduation) |
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Subjects: | Physics, Optics |
ID Code: | 6918 |
Deposited By: | Jérémy Ahuir |
Deposited On: | 19 avr. 2019 09:22 |
Dernière modification: | 19 avr. 2019 09:22 |
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