THE GALACTIC AND EXTRA-GALACTIC ALL-SKY MWA EXTENDED SURVEY

Public Information

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.

For Astronomers

As part of the MWA Collaboration policy on open access, the raw visibilities of each year of GLEAM-X observing are public 18 months after observing finishes.

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..

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

The GLEAM-X survey will cover the entire sky south of Dec +30, and will use the extended configuration of the MWA, which will be described in Wayth et al. in prep. 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 strips 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.

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

Survey progress

GLEAM observing began in January 2018 and the first semester concluded in June 2018. The second semester is planned for 2019-B, subject to the availability of the extended configuration in that proposal round.