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Research Interests

My greatest astronomical and astrophysical interests are in:

  • cosmology - the study of the universe's origin, fate, and evolution on the largest scales of size and time
  • extreme gravity - when gravity is so strong (near a black hole, for instance) that time and space blend into one another
  • radio interferometry - an involved technique for networking radio antennas together to produce the highest resolution images ever created by mankind

Current Research Background

Currently, my master's research is related to all three of my interests. In recent years, much attention has been directed towards the study of long radio transients, bursts of radio emission believed to be caused by a range of extreme astrophysical events:

  • The deaths of massive stars, supernovae, can produce extremely energetic jets of material, shot out at relativistic speeds, along the axis of the star's rotation. The immediate event leads to long gamma-ray bursts (GRBs), which last from seconds to minutes, but in the aftermath the jet of extremely hot material collides with the local interstellar medium and produces radiation spanning the whole electromagnetic spectrum as ejected electrons spiral around magnetic field lines. The radio afterglow created by this 'Synchrotron emission', which can last for years, is an independent window into the study of these events from the monitoring of the GRB itself.

  • Supermassive black holes (SMBHs), now believed to exist in the core of nearly every major galaxy, occasionally tear apart stars that pass too close, beginning a sort of feeding frenzy. These are called 'tidal disruption events' (TDEs), and create a radio transient with a similar mechanism to the supernovae, as the SMBH winds up a relativistic jet in a similar manner. This may be complemented by radio emission that does not come from the jetted material, as some of the shredded star is flung into the surrounding medium.

The study of the radio transients associated with these events is of great scientific value to the study of these phenomena. In the majority of cases, the electromagnetic radiation we receive is the only information we can use to study them; the event itself is far too small on the sky to resolve what is physically going on. Until recently these events were almost exclusively detected by observations in high-energy light (UV, X-ray, and gamma ray), but the next generation of radio telescopes have the potential to help monitor and observe these events. This can help massively to constrain our models and simulations of what is actually going on (since the radio emission mechanism is different from that of the higher energy light), can help greatly to positively identify these events (TDEs, for example, can look an awful lot like GRBs but necessarily occur in the centers of what could be very distant galaxies - the high resolution images radio astronomy can help confirm that the transient came from the centre of a galaxy), and overcomes several other challenges with short-wavelength astronomy. Radio astronomy can be done from the ground with larger telescopes, whereas the UV and higher energy light used to otherwise monitor these events is (thankfully) blocked almost completely by our atmosphere, necessitating the use of high-demand, low-resolution space-based telescopes. Radio observations may also allow us to detect otherwise hidden events, since light more energetic than infrared is absorbed by galactic dust, whereas radio light passes unimpeded.

All of these factors make radio astronomy, and especially radio interferometry, a promising and potentially very useful way of studying these phenomena.

My Research

For my master's research project, I am predicting how many long radio transients of many types we may be able to see with one of the world's best, up and coming, radio observatories, the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD), which is currently under construction at the Dominion Radio Astrophysical Observatory in Penticton, BC, Canada. Several factors will make this radio interferometer an excellent tool for searching for long radio transients:

  • CHORD will have an unusually large field of view for a radio interferometer. This will help survey our enormous sky for these events, which are found by noticing changes in repeated observations in the same location of the sky

  • CHORD is designed for very sensitive, precision cosmology, and generally is a very sensitive instrument, helping detect events with would have been too faint for other telescopes

  • CHORD is a radio interferometer, and as such has impressive angular resolution. This helps positively identify and classify radio transients, preventing false positives and reducing the number of true events that are cut out of datasets out of fear that they could be false positives

I am in the opening phase of this research, and have much learning to do myself. Stay tuned for developments as this work continues!