New capability: high-time resolution recording added to the MWA
Some objects in the Universe happen so quickly that we need our telescopes to work on a high-time resolution (less than one second). Such data let us answer questions within high impact research areas such as pulsar emission and the recently detected, possibly extragalactic, bursts of radio emission called fast radio bursts (FRBs).
The original design of the Murchison Widefield Array (MWA) – the low-frequency precursor 0
instrument to the Square Kilometre Array (SKA) in Western Australia – lacked the ability to access these data since it was devised purely as an imaging radio interferometer. In their recent paper, CAASTRO researchers Dr Steven Tremblay, Dr Stephen Ord, Dr Ramesh Bhat, Prof Steven Tingay, as well as other CAASTRO members, describe how high-time resolution recording capabilities have recently been added to the MWA. Their system can record the 100 microsecond and 10 kHz resolution voltage data from the MWA. The team was able to implement an off-the-shelf solution to add this capability to the MWA’s software correlator.
Pulsar observations were critical in the commissioning of this new system. The spin periods of the assorted pulsars, ranging from 5.75 to 3754 milliseconds, were used in the evaluation, as well as other characteristics. Since the signal from each pulsar travels through a different amount of ionised interstellar medium on its journey to Earth, each experiences a different amount of dispersive delay across the observed band. Being able to compensate for this and recover the pulsed signal is another assessment of the system’s performance. This new system paves the way forward for southern hemisphere low-frequency high-time resolution radio science.
S.E. Tremblay, S.M. Ord, N.D.R. Bhat, S.J. Tingay et al. in PASA (2015) “The High Time and Frequency Resolution Capabilities of the Murchison Widefield Array”