N.D.R. Bhat1,2
Abstract.
Exploration of the transient Universe is an exciting and fast-emerging area within radio astronomy.
Known transient phenomena range in time scales from sub-nanoseconds to years or longer, thus
spanning a huge range in time domain and hinting a rich diversity in their underlying physical processes.
Transient phenomena are likely locations of explosive or dynamic events and they offer tremendous
potential to uncover new physics and astrophysics.
A number of upcoming next-generation radio facilities and recent advances in computing and
instrumentation have provided a much needed impetus for this field which has remained a relatively
uncharted territory for the past several decades.
In this paper we focus mainly on the class of phenomena that occur on very short time scales
(i.e. from ~milliseconds to ~nanoseconds), known as fast transients, the detections
of which involve considerable signal processing and data management challenges, given the high time
and frequency resolutions required in their explorations, the role of propagation effects to be
considered and a multitude of deleterious effects due to radio frequency interference.
We will describe the techniques, strategies and challenges involved in their detections and review the
world-wide efforts currently under way, both through scientific discoveries enabled by the ongoing
large-scale surveys at Parkes and Arecibo, as well as technical developments involving the
exploratory use of multi-element array instruments such as VLBA and GMRT.
Such developments will undoubtedly provide valuable inputs as next-generation arrays such as LOFAR
and ASKAP are designed and commissioned. With their wider fields of view and higher sensitivities,
these instruments, and eventually the SKA, hold great potential to revolutionise this relatively nascent
field, thereby opening up exciting new science avenues in astrophysics.
Keywords: surveys -- telescopes -- transients -- methods: observational -- techniques: interferometric -- pulsars: general
1Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
2Australian Research Council Centre of Excellence for All-Sky Astrophysics (CAASTRO)