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Unveiling the faintest nuclear activity using high-resolution stacking

Very Long Baseline Interferometry provides the sharpest view on the radio sky, with routine milliarcsecond resolution observations which can unequivocally identify galaxies with intense accretion onto the central supermassive black hole (known as Active Galactic Nuclei; AGN). Some AGN are luminous in other wavebands, but have extremely weak radio emission below the sensitivity of the VLBI observations, hence the origin of the emission is unknown. Initial studies contradict each other suggesting that the radio emission originates from either the central AGN or star-formation. A alternative way of investigating these ultra-faint populations is to use stacking (see Fig. 1). This technique combines the signals of multiple pre-selected sources to increase the sensitivity and infer the nature of these objects as a whole. However, in order to obtain a successful stacking signal, we require prior catalogues which have much higher positional accuracy than the waveband we are stacking in. This means that VLBI observations cannot use conventional stacking techniques. In this Masters project, we will attempt to stack high-resolution VLBI observations, beating the astrometric limitations of classical stacking. Using a suite of VLBI simulations, the student will develop upon a novel algorithm in order conduct such stacking. With successful implementation, we will test this upon real data with the aim of uncovering the origin of radio emission in AGN selected in other wavebands.
Node This Project Is Offered On: 




Requirements for students to address: 
A candidate with strong programming skills (e.g. Python) would be preferable for this sort of project. Some knowledge of UNIX would also be advantageous.
Research Area: 

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