The Voltage Capture System (VCS; Tremblay et al. 2015) provides access to high time and frequency resolution voltage data from the MWA. The data recorded are the critically sampled voltages streaming from the fine-PFB stage of the standard MWA signal chain (i.e. before the correlator), thus the data have 100 μs time resolution and 10 kHz frequency resolution.
The primary science driver for the VCS is pulsars, exploring a frequency range in which the vast majority of pulsars have very little or no published information. The science cases are numerous, but include:
- pulsar emission mechanism, i.e. studying phenomena such as giant pulses, sub-pulse drifting, and emission intermittency,
- survey science, i.e characterising known pulsars, detection of new pulsars, and regular monitoring of targets of interest, and
- propagation effects induced by the interstellar medium, i.e pulse broadening/scattering, scintillation and dispersion measure variations (in time and frequency).
There are also opportunities in terms of Solar science (e.g. solar bursts, interplanetary scintillation) and other fast-transient science cases where high time resolution is desirable (e.g. triggering on GRBs, FRBs and other exotic phenomena).
Fundamentally, VCS data is much larger than normal MWA observations, providing ~28 TB/hr of data. This also limits the duration of any single observing run to ~1.5 hours.