Science

The bursting and transient universe is one of the major areas of unexplored phase space. Traditional observations have greatly expanded our knowledge of the steady-state properties of many astrophysical phenomena, but the physics of the dynamic universe remains elusive due to the difficulty of observing short lived and impulsive events. Across all areas of astronomy, transient science has become a major focus of new and proposed observatories including ROTSE, SNAP, Swift, GLAST, LIGO, and Ice Cube. Since radio can observe the magnetic fields and non-thermal processes which drive many dynamic astronomical events, transient radio observations could provide key observations for understanding the bursting and transient universe. Potential sources of radio transient emission fall into the four broad categories below.

Gamma Ray Bursts (GRBs) and radio supernovae may both produce short and long duration transient radio signals. The “afterglow” emission from GRBs and supernovae light curves provide signals at the upper frequencies of the MWA which are delayed from the initial explosion and slowly rise in intensity over a few weeks to months.

The Sun and Jupiter are well-known sources of transient radio emission, and the MWA should extend these studies to nearby stars and planets. While the MWA does not quite have the sensitivity to observe solar type activity from nearby G-class stars, it will observe the stellar transient activity of more active stellar systems. The radio bursts from hot-Jupiter type planets may also be detected, offering insight into the magnetic fields of these unique objects and the solar winds of their parent stars.

The launching of relativistic jets and knots from black hole accretion systems produces bright x-ray flares, and is a poorly understood phenomenon central to understanding the physics behind Active Galactic Nuclei (AGN), micro-quasars and gamma-ray bursts. Simultaneous transient radio and x-ray observations could provide crucial insight into the physics behind the launching of relativistic jets.

The MWA transient survey opens a new area of phase space, and may detect unexpected transient sources. Some of the more exotic possibilities include coincident observations with LIGO and the neutrino detectors, or SETI observations.