The Spatially Resolved Kinematics, Star-Formation and Chemical Adundances of High-Redshift Galaxies

One of the most compelling science cases for the construction of the next generation of telescope (such as the 40-m Extremely Large Telescope; ELT) is to study the dynamics, chemistry and star-formation in distant galaxies on scales comparable to local star-forming regions (ie such as the Pleideas). Currently, even with the best 8 and 10m class telescopes, only the largest star-forming regions can be resolved. Yet, much higher resolution observations are desperately needed to tell us why the first galaxies that formed in the Universe (ie seen 10-12 billion years ago) are so more efficient at forming stars than galaxies today. One indication comes from theoretical models which predict that the collective effects of star-formation and stellar explosions (supernovae) drive galactic superwinds out of the galaxy (similar, but much more powerful to those seen in M82). This phenomenon prevents the galaxies from forming too many stars, and may offer an explanation of why only 10% of baryons in the local universe are locked up in stars. Observations of galaxies on the scales required to measure the properties of star- forming regions and their energetics (and hence effect on their local environment) are currently far beyond the capabilities of current facilities, yet these are the measurements which are key to guiding theoretical models. However, significant progress can be made by using the natural striking phenomenon of gravitational lensing. Massive galaxy clusters magnify the images of background galaxies which serendipitously lie behind them, producing striking, multiply imaged arcs. This natural lensing effect produces both a boost in flux and in apparent size: the magnification factor can reach a factor 50x. By observing these galaxies we can push the telescope performance into a new regime: for a canonical amplification factor 15x, this effectively reduces the diffraction limit by a factor 4x, giving a 10m telescope the performance of a 40m telescope -- i.e. delivering the performance expected for ELT, still a decade away. Targeting highly magnified galaxies therefore allows us to probe the intrinsic properties of galaxies on scales corresponding to individual star-forming regions. This data allows key questions to be probed: what are the properties of star-forming regions in young galaxies? are the physical conditions very different to local galaxies? How does this effect the interpretation of large redshift surveys which map the demographics of the population as a whole? what is the interaction between star-formation and super-wind outflows? Do super-winds have the form of 'bubbles', or are they more highly collimated? What is the fate of the out-flowing gas (the fate of the galaxy will be very different if the outflows are collimated compared to bubble-like). By selecting very intensely star-forming galaxies we can also bridge the gap between 'normal' galaxies and more extremely luminous galaxies which can be studied without the aid of lensing. Are intensely star-forming galaxies simply scaled up versions of galaxies selected at other wavelengths, or are there other processes involved? Do the super-massive black holes in massive galaxies have more of an impact on the galaxy than in smaller galaxies? Is the type of star-formation in intense starbursts the same as those in more quiescent galaxies, or are the physical conditions very different? My proposed research is aimed at spatially resolving the dynamics, chemistry and distribution of star-formation within galaxies in the distant Universe, focusing on answering these questions.