GLEAM-X

Description

The GLEAM-X survey covers the entire sky south of Dec +30, using the extended configuration of the MWA, as described in Wayth et al. 2018. A description of the science motivations and survey methodology for GLEAM-X can be found here. As in the original GLEAM survey, the sky has been divided into seven drift scans in declination and five frequency ranges as summarised below. The declinations were chosen such that the peak in the primary beam response for a given setting corresponds approximately to the half power point of the neighbouring beam along the meridian at 150 MHz. The instantaneous frequency coverage of the MWA is 30.72 MHz, so the frequency range between 72 and 231 MHz was divided into five bands that provided near contiguous coverage but avoided the band around 137 MHz that was contaminated by satellite interference. 

The observing was executed as a series of four-week-long campaigns where a single declination setting was observed in a night, covering a strip approximately 10 to 12 hours in length, depending on the time of year. The Sun can be bright and time-variable at MWA frequencies, so drift scan observations were only performed at night. Within a night, the observing was broken into a series of 120 s scans for each frequency, cycling through all five frequency settings over 10 minutes. Within a scan, typically 108 s of usable data were collected. Every 2 hours throughout the night, a calibration field was observed over all five frequency settings, again as a set of 120 s scans totalling 10 minutes. Each declination strip received two meridian drift scans (HA=0), one at HA=+1, and one at HA=-1, to improve (u.v)-coverage and sensitivity. 

Data

GLEAM-X observing began in January 2018 and final observations were completed in 2020. Both continuum and polarisation studies using the GLEAM-X data had been released.

The survey description paper is now published in PASA. Our first data release is available via AAO Data Central, with the second data release covering the South Galactic Pole region to be released in 2024.

If you’d like to read about the unusual long-period radio transient we discovered in GLEAM-X, you can find the paper here. 

For Astronomers

GLEAM-X is still being processed. Check back here for updates on survey progress as they come in! In the meantime, check out the original GLEAM survey. 

To join the team or work on pre-release GLEAM-X data, please contact Natasha Hurley-Walker via nhw@icrar.org.

As per the MWA large project policy, any member of the MWA collaboration can access raw GLEAM-X data for their science. This can be downloaded from the MWA node of the All-Sky Virtual Observatory.