Observational radio maps

Details on how to obtain the observational maps presented in:

• N. Fornengo, R.A. Lineros, M. Regis, M. Taoso
• "The isotropic radio background revisited"
• http://arxiv.org/abs/arXiv:1402.2218
• (JCAP 1404 (2014) 008)

22 MHz - downloaded from: http://www3.mpifr-bonn.mpg.de/survey.html and re-projected into the Healpix format (Map^)

45 MHz - downloaded from: http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/525/A138 and re-projected into the Healpix format (Map^)

408 MHz - downloaded from LAMBDA website: http://lambda.gsfc.nasa.gov/product/foreground/haslam_408.cfm

820 MHz - downloaded from: http://www3.mpifr-bonn.mpg.de/survey.html and re-projected into the Healpix format (Map^)

1420 MHz - Patricia Reich, private communication: re-projected into the Healpix format

2326 MHz - downloaded via anonymous ftp from: ftp://cdsarc.u-strasbg.fr/catv/A+A/410/847/ (Map^)

^ The maps have been obtained by regridding the original Cartesian-projected maps into a much finer grid, then filling pixels of an intermediate map in the HEALPix tassellation scheme with linear size of pixels close to the one of the regridded Cartesian map, and finally dowgrading the intermediate HEALPix map into an HEALPix map with resolution given by NSIDE=64. Although this is more than sufficient for the purposes of this work, we warn the user that if interested in performing studies at angular scales close to the angular resolution of the original survey, a more sophisticated processing might be in order. In case of use of the above maps, we also remind to cite not only (JCAP 1404 (2014) 008), but the original source as well.