Telescope

What makes the MWA, the MWA.

Data

The MWA records the low-frequency radio sky in the form of radio astronomy data.

The sheer volume of data produced by the MWA requires high-end computing, networking, and software to deal with the data deluge. The raw data rate into the correlator is 136 Gbit/s (17 GB/s) which is the equivalent of more than 4 HD movies every second. The data ultimately ends up being transported and archived at the Pawsey Supercomputer Research Centre, where, as of September 2022, the MWA has 43 PB of data – the equivalent storage of 1.3 million 32GB iPads, or 43,000 home computers!

The MWA data flow is shown below, and can also be viewed as an animation on the MWA Youtube channel.

Taking data

Twice a year, the MWA Director puts out a Call for Proposals, which astronomers answer to apply for time on the telescope. The proposals are usually for projects that fall within one of the MWA Key Science Cases.

The proposals are then reviewed by the Time Allocation Committee. To see the full list of observing awards (projects and astronomers that have had approved time on the MWA), head to our wiki: Observations

An observing proposal contains both scientific and technical details that allow the operations team to schedule the observations in the upcoming semester.

Metadata

The MWA is operated remotely through an interface to a Monitor and Control (M&C) software package resident on a dedicated computer located within the CSIRO Data Processing Facility at the MWA site.

The M&C software maintains a state-based description of the hardware and an event-driven database describing the observation scheduling of the instrument. M&C software commands several elements of the system including pointing and tracking of the beamformers, frequency selection of the receivers, and parameters for the correlator.

The M&C system contributes to the MWA archive by storing instrument “metadata” into an external database. This includes both the instrument configurations for each observation and also housekeeping information collected from various hardware components.

More M&C information

Data flow

Radio waves emitted by various celestial objects are recorded as voltages from each tile which are then digitised and channelised by the receivers. The data is then sent from the receivers into the MRO Control Building, where media converter servers take the bespoke receiver data format and convert it into regular ethernet packets. Next generation receivers already send their data as regular ethernet packets, so media conversion isn’t required in their case.

The network packets are ingested by the MWAX correlator servers (or saved to disk when in voltage capture mode) which then performs further channelisation and correlation to produce visibility data. The visibility data are then written to disk as files and transferred via 800km of high-speed fibre optic cable to Curtin University’s data cache. The data are then transferred into the MWA data archive at the Pawsey Supercomputing Research Centre.

Archive and outputs

The MWA data archive is located in Perth at the Pawsey Supercomputing Research Centre, and is comprised of two systems named Acacia and Banksia.

Acacia is a 60PB disk-based storage system, of which 10PB is reserved for use by the MWA. Banksia is a 70PB tape storage system, with 40PB being reserved for use by the MWA. Therefore, the total available space for the MWA archive is 50PB, or 50 million gigabytes.

Data are provided to the international astronomy community via the MWA node of the All-Sky Virtual Observatory (MWA ASVO). Here, researchers are able to browse a complete history of all observations ever taken by the telescope, with the ability to drill down by user-specified criteria. Users then submit job requests to the MWA ASVO, which extracts and provides the relevant data from the archive.

Significant processed data products produced by the MWA Collaboration (such as the initial release of the GLEAM survey) are also available via various international scientific databases for analysis and interpretation.

Once MWA data are processed and analysed by astronomers, the outputs are often published in peer-reviewed journals. We keep track of the papers produced by members of the MWA Collaboration, which can be viewed at the link below.

MWA Papers Library

Be Informed

Findings worth tuning into

MWA astronomers are leading the way at low frequencies – read up on the latest news.