Final Report Summary - SIMPLE-FEEDBACK (Fedback in low mass galaxies at z>1 : a SIMPLE study)
Project aims and objectives
Galaxy formation is very inefficient. On average, only 5 % of baryons made it in galaxies. 'Why is galaxy formation so inefficient?' is one of the most fundamental questions in modern astrophysics. This question is directly related to the mechanisms that regulate gas supply/gas losses. A large number of observations have shown that galactic outflows are important in regulating the gas content of galaxies. However, in spite of rapid progress, our current knowledge of the physical properties of galactic winds is still in its infancy. Little is known on the mass outflow rate, for instance.
The main goal of this project is to understand the physical properties of galactic winds produced by star-forming galaxies and how they might depend on the galaxy properties (such as mass, star-formation rate, etc.). In order to achieve our main objective, we have selected a dozen low-mass galaxies 'caught in the act' of producing super-winds half way across the universe (at redshift z = 1) where the wind signature is seen in background quasar spectra. For each of these galaxies, we have obtained detailed 2-dimensional kinematics with the SINFONI instrument of one of the Very Large Telescopes (VLT) of the European Southern Observatory (ESO). For each of the quasars, we also have detailed absorption kinematics along the Quasi-stellar object (QSO) line-of-sight, also obtained at the European Southern Observatory.
The objectives planned for this project were to exploit the available data in order to (i) assess the dynamical state of the starbursts, and (ii) extract the physical properties of the intervening gas. We have analysed the data, computed the star-formation rates, the dynamical masses of the galaxies from the SINFONI maps. Another key aspect of our project is to understand the absorption kinematics in the context of galactic winds and we recently successfully achieved this milestone. For this, we needed to model the galactic outflow. Using a simple bi-conical flow, we could demonstrate that the absorption kinematics seen in the quasar spectra could be very well accounted for.
Galaxy formation is very inefficient. On average, only 5 % of baryons made it in galaxies. 'Why is galaxy formation so inefficient?' is one of the most fundamental questions in modern astrophysics. This question is directly related to the mechanisms that regulate gas supply/gas losses. A large number of observations have shown that galactic outflows are important in regulating the gas content of galaxies. However, in spite of rapid progress, our current knowledge of the physical properties of galactic winds is still in its infancy. Little is known on the mass outflow rate, for instance.
The main goal of this project is to understand the physical properties of galactic winds produced by star-forming galaxies and how they might depend on the galaxy properties (such as mass, star-formation rate, etc.). In order to achieve our main objective, we have selected a dozen low-mass galaxies 'caught in the act' of producing super-winds half way across the universe (at redshift z = 1) where the wind signature is seen in background quasar spectra. For each of these galaxies, we have obtained detailed 2-dimensional kinematics with the SINFONI instrument of one of the Very Large Telescopes (VLT) of the European Southern Observatory (ESO). For each of the quasars, we also have detailed absorption kinematics along the Quasi-stellar object (QSO) line-of-sight, also obtained at the European Southern Observatory.
The objectives planned for this project were to exploit the available data in order to (i) assess the dynamical state of the starbursts, and (ii) extract the physical properties of the intervening gas. We have analysed the data, computed the star-formation rates, the dynamical masses of the galaxies from the SINFONI maps. Another key aspect of our project is to understand the absorption kinematics in the context of galactic winds and we recently successfully achieved this milestone. For this, we needed to model the galactic outflow. Using a simple bi-conical flow, we could demonstrate that the absorption kinematics seen in the quasar spectra could be very well accounted for.