GLEAM 72-103: GaLactic and Extragalactic Allsky MWA Survey

Short name[s] used to specify survey: GLEAM72-103, GLEAM 72-103,GLEAM 72-103 MHz, GLEAM1, GLEAM 1

Description
GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination 30 degrees at frequencies between 72 and 231 MHz. It was made with the Murchison Widefield Array (MWA) using a drift scan method that makes efficient use of the MWA's very large field-of-view. The survey is described in Wayth et al. (2015) and the website at http://mwatelescope.org/science/gleam-survey.

The data presented here are from the first year of GLEAM observing, published in Hurley-Walker et al. (2017). The 25,000 square degrees of available sky excludes the Galactic Plane, the Magellanic Clouds, Centaurus A, and a few other small regions described in the catalogue paper.

The most sensitive and highest-resolution image is the 170-231MHz image which was used for all source-finding in generating the catalogue. It has a resolution of approximately 2.2 x 2.2/cos (dec + 26.7) arcmin at this frequency. However, due to ionospheric distortions, the final resolution of the survey varies by ~10% over the sky, with a direction-dependent PSF.

The SkyView data for the GLEAM surveys was extracted using the team's cutout server, into small (3 degree) raw cutouts over the region covered by the GLEAM survey. These cutouts have somewhat variable size and resolution. The default scale (i.e., pixel size) used for SkyView images is given in the table below.

SkyView resamples the cutouts retreived from the GLEAM web site into the image geometry requested by the user. Only four wide-band datasets are included here. The table below gives the frequency range, central frequency and a typical pixel scale for each of these bands.
GLEAM Bands In SkyView
Band fmin (MHz) fmax (MHz) fC (MHz) Pixel scale (")
1 72 103 88 56
2 103 134 118 44
3 138 170 155 34
4 170 231 200 28
These data and 20 narrower bands are available through the team web site.

To minimize resampling artifacts, this survey defaults to the Lanczos third order resampler.

Provenance Source data extracted as cutouts from GLEAM cutout server.
Copyright Natasha Hurley-Walker for the GLEAM teeam.

Permission is granted for publication and reproduction of this material for scientific and educational purposes. When using data products provided in this release, it is requested that authors refer to the publications Wayth et al. (2015) and Hurley-Walker et al. (2017).

Regime Radio
NSurvey 4
Frequency 88 MHz
Bandpass 72-103 MHz
Coverage Declination < +25 excluding the Galactic plane
PixelScale ~ 56
PixelUnits Jy/beam
Resolution > 4' but varies with declination and frequency. See references.
CoordinateSystem Equatorial
Equinox ICRS
Projection Zenital Equal Area (ZEA)
Epoch 2013-08-09 to 2014-06-18
Reference Wayth et al. (2015), GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey and
Hurley-Walker, et al. (2017), GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue and
GLEAM web site