Joshua Rich

PhD candidate, 2008

The Inter-Stellar Medium is a violent, turbulent place undergoing constant transformation through the energetic processes including star-formation.

Astronomy is a science which cannot be done without good quality observations.  It is therefore imperative that the process of taking observations is well understood, and the process of transforming the raw observations into a usable data-set from which astronomical results can be measured is done with care and clarity.

The art of astronomical observations lies in reconstructing the highest fidelity representation of the sky, given the inherent limitations of the data, which are always to some degree affected by atmosphere, instrument, technique or telescope. Some kind of processing always needs to be applied to minimize these issues and produce the most accurate representation of the astronomical source of interest.

Achieving the best possible resolution and contrast in astronomical imaging allows the probing of fine-scale structure in unprecedented detail, providing an insight into some of the smallest events occurring in the universe from which the most violent, energetic and easily observable events are intimately related.  For example, high contrast, high resolution radio imaging of neutral hydrogen provides a detailed view of the processes and structures shaping the Inter-Stellar Medium (ISM) in nearby galaxies.

The typical picture of the ISM is a mixture of gas, dust and cosmic rays encompassing the space between the stars in a galaxy.  It is also a violent, turbulent place undergoing constant transformation through the energetic processes including star-formation.  Supernovae, gamma-ray bursts, high-velocity cloud collisions and even the nearby environment of the galaxy itself are all believed to shape the ISM into an intricate tapestry of holes, shells and bubbles that defines a complex set of tunnels, networks and cavities of under-densities through the tenuous gas and dust.  It is apt then that it has been described as 'the violent interstellar medium' and the 'cosmic bubble bath'.

Research School of Astronomy and Astrophysics (RSAA) PhD student Joshua Rich is studying both of these areas, for several end goals. The first goal is to improve the state of imaging techniques and astronomical software processing, particularly in light of the next-generation radio and optical astronomical facilities which will be producing a huge amount of data that current techniques and software may not adequately handle. The second goal is to push current radio facilities such as the Very Large Array to its limits, allowing a probing of the fine-scale structure in the ISM with the highest resolution data, to understand the events that lead to star-formation in nearby galaxies.

Joshua Rich completed a dual degree in Applied Physics and Information Technology at Central Queensland University in Rockhampton, Queensland before taking a long trek south to Canberra to complete his Honours year at RSAA, ANU. 

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