Description
Roger et al. (1999) presented a map of the 22 MHz radio emission between declinations -28° and +80°,
covering ~73% of the sky, derived from observations with the 22 MHz radiotelescope of the
Dominion Radio Astrophysical Observatory (DRAO).
The resolution of the telescope (EW x NS) is 1.2° x 1.7° secant(zenith angle).
Roger et al. emphasize that the main value of the data lies in the representation of structure
larger than the beam.
The strongest point sources (Cas A, Cyg A, Tau A and Vir A) have been removed from the map.
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The Centre d'Analyse de Données Etendues group used the data to form an all-sky HEALPix format map
following the method described in Appendix A of Paradis et al. 2012, A&A, 543, 103, ADS.
Their HEALPix map is mirrored here.
The map is in units of K brightness temperature.
Map pixels are set to a sentinel value of -32768.0 for unobserved regions and
for regions affected by sidelobes around Cyg A, Tau A, and Vir A. Provenance: DRAO, MPI for Radio Astronomie. This is a service of NASA HEASARC.
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