Data

Observational Status

POSSUM observations are proceeding! Click here for a summary of the fields observed so far.

POSSUM data can be obtained by searching in the CSIRO ASKAP Science Data Archive (CASDA). POSSUM’s project code for Pilot Survey data is AS103.

Presently, the CASDA interface provides access to:

Continuum (Stokes I) “component” and “island” catalogs, after mosaicing of the 36 PAF beams
Stokes I and V images and continuum cubes, after mosaicing of the 36 PAF beams:
- Continuum cubes (1 MHz spectral resolution), before convolution to a common beamsize
- Continuum cubes (1 MHz spectral resolution), after convolution to a common beamsize
- Taylor-0 images (frequency-averaged) after convolution to a common beamsize
Visibility datasets for each of the 36 PAF beams
“Ancillary” image data products, including:
- Mean, background, and noise maps
- Source finding model map and residuals
- Stokes I and V Taylor 1 images

Hint: to obtain cut-out images instead of full widefield images and cubes, there are two options:

Use the CASDA web interface. In the CASDA Search Results interface, click the “Actions” (“i”) icon next to the desired image product, and choose “Generate cut-out” (note that you must be logged in to CASDA)
Use CASDA VO Services. Check out the examples provided here to discover how to proceed.

Data products generated by the ASKAP pipeline will be processed by the Australian SKA Regional Centre (AusSRC) and transported to the Canadian Initiative for Radio Astronomy Data Analysis (CIRADA) for final processing through the POSSUM pipeline. The pipeline will use RM-Tools to produce:

1D pipeline outputs (for every source catalogued by EMU):
- IQU frequency spectra
- RM spectra
- Catalog entries summarising polarization properties
3D pipeline outputs:
- 3D Faraday depth cubes of the full field of view
- 2D maps of derived polarization properties