Measurement of galaxy internal kinematics in slitless spectroscopy

Slitless spectroscopy has long been considered as a complicated and confused technique because of its self- and cross-confusion effects. However, since the era of the Hubble Space Telescope (HST) instruments which offer a low background and fine spatial resolution, slitless spectroscopy has become an adopted cosmological survey tool to study galaxy evolution from space. Within this context, we investigate its application to single object studies. In recent surveys, the spectra analysis is usually done using backward extraction which mixes spatial and spectral properties and therefore does not take into account self-confusion effect. The goals of this PhD is firstly to include this effect which degrades the effective spectral resolution (which depends on the extent of the source), in order to make the redshift and other integrated spectral features measurements more accurate. We also explore the feasibility to measure spatially resolved quantities such as galaxy kinematics. We build a complete forward model to be quantitatively compared to actual slitless observations. The model is tested on selected observations from 3D-HST and GLASS surveys, to estimate redshift and kinematic parameters (modeling the galaxy rotation curve) on several galaxies. Our forward approach allows to mitigate self-confusion effect, and therefore to increase the precision of redshift measurements. In a sub-sample of well-resolved spiral galaxies from HST surveys, it is possible to significantly constrain galaxy rotation curve parameters. We also study the systematics effects induced by the hypothesis of our model by building slitless simulations with the data of the integral field spectrograph survey MaNGA. These simulations suggest that the precise measurement of the kinematics parameters is difficult for most of the current slitless observations. Nevertheless, they point out that this forward model constrains significantly well the redshift. Finally, this work is promising for future large slitless spectroscopic surveys such as Euclid. (author)