Galaxy-scale jets with new extragalactic radio surveys

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Extragalactic jets from supermassive black holes are known to play an important role in the process of how galaxies evolve. Research in this area over the last decade has focused particularly on powerful jets in the centres of rich galaxy clusters, where jets appear to regulate star formation in massive galaxies - a process now incorporated into most cosmological simulations of galaxy formation. But smaller jets contained within their host galaxies can also have a powerful effect on the scale of individual galaxies, as we have found from recent X-ray studies measuring the impact of their shocks (e.g. Croston et al. 2007, 2009, Mingo et al. 2011, 2012, Heesen et al. 2014). Their low radio luminosity and small size mean that these jets have been difficult to identify in previous radio surveys. For this reason, the demographics of the population, and the role of these small-scale jets in the high-redshift Universe, are not understood. Similarly, direct measurements of their impact via X-ray follow up have only been possible for a handful of objects.This project will involve exploiting new low-frequency surveys of the extragalactic sky with LOFAR (the Low-Frequency Array), which have the sensitivity, resolution and image fidelity to identify and characterize galaxy-scale jets. By cross-matching this population with data at other wavelengths, it will be possible to answer questions about how common they are, and how their radio properties relate to their black hole mass, accretion behaviour and environment. There is also the possibility to work on new and archival X-ray observations to measure shock properties in individual objects.