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`Big Bangs and Black Holes: Connecting Fundamental Physics and 
 Observational Astrophysics'

Abstract:
Although theoretical concepts of black holes date back over 200 years,  
they remained in the realms of mathematical speculation until the late  
20th century. Today, the existence of black holes - stellar and  
supermassive - is no longer debated; instead, the physics of their  
creation and the far-reaching consequences of their existence remain  
at the forefront of modern astronomy. Optical light, to which human  
eyes are most sensitive, has been harvested throughout human history,  
enriching ancient cultures and helping our forebears realise that the  
Earth does not lie at the centre of the Universe. However, this light  
represents only a small fraction of the total light available for  
collection; technological advances in the 20th and 21st centuries have  
ensured that we can collect light ranging from the highest energy  
gamma rays, through X-rays to long wavelength radio waves; perhaps  
more importantly, the information gathered from astronomical images  
can be augmented with techniques such as spectroscopy and polarimetry,  
which allow the motions of stars and gas in distant galaxies to be  
measured or magnetic fields in distant stellar explosions to be  
probed. Although black holes themselves do not emit radiation,  
experimental confirmation of their existence resulted from such  
impressive technical advances. This lecture will introduce some of the  
most powerful phenomena in the Universe that are driven by black  
holes, big and small - Active Galactic Nuclei and Gamma Ray Bursts.  
These two classes of objects may share many physical processes but  
change their observed properties on vastly different timescales  
(millions of years, minutes, seconds);  I will compare and contrast  
our current understanding of them, gained by combining multi- 
wavelength, multi-epoch imaging with spectroscopy and polarimetry to  
decode the information in the detected light. With a growing  
understanding of these phenomena, I will show that increasingly rich  
astronomical datasets may be mined to provide independent constraints  
on theories of gravity, such as string phenomenology and quantum  
gravity.
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