
THE GALACTIC AND EXTRA-GALACTIC ALL-SKY MWA EXTENDED SURVEY
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 will be found in Hurley-Walker et al. (in prep). 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 are 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 is divided into five bands that provide near contiguous coverage, but avoid the band around 137 MHz that is contaminated by satellite interference. The observing is executed as a series of four-week-long campaigns where a single declination setting is 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 are only performed at night. Within a night, the observing is 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 are collected. Every 2 hours throughout the night, a calibration field is observed over all five frequency settings, again as a set of 120 s scans totalling 10 minutes. Each declination strip will receive two meridian drift scans (HA=0), one at HA=+1, and one at HA=-1, to improve (u,v)-coverage and sensitivity.
Survey progress
GLEAM-X observing began in January 2018 and final observations are planned for Q3 2022. We plan to release both continuum and polarisation studies using the GLEAM-X data.
The survey description paper is available on arXiv and will be published in PASA in coming weeks. Our first data release will shortly be available via AAO Data Central.
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 observed and 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 This email address is being protected from spambots. You need JavaScript enabled to view it.. 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.
Pointing Declinations (deg)
-72, -55, -40.5, -26.7, -13, +1.6, +18.3
Pointing HAs (hours)
0, -1, 1
RA ranges (hours)
4 to 21 (2018-A); 17 to 8 (2019-B)
Central Frequencies (MHz)
87.68, 118.4, 154.24, 184.96, 215.68
Frequency resolution (kHz)
10
Time resolution (s)
0.5
Comparison to other surveys
Survey Name
Frequency Range
Sensitivity
Angular resolution
Sky area
(MHz)
(mJy/beam)
(arcsec)
(sq deg)
GLEAM-X
72 - 231
1 - 2
~45
30,000
GLEAM
72 - 231
6 - 10
~100
30,000
MSSS-LBA
30 - 74
~15
~100
20,000
VLSS
74
100
80
30,000
MSSS-HBA
120 - 160
~5
~45
20,000
TGSS
150
2 - 5
25
37,000
MWACS
120 - 180
50
~180
6,100
MRC
408
~150
~100
24,000
SUMSS
843
1
45
8,100
NVSS
1400
0.45
45
35,000