All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz

摘要

Aims: We study the Galactic large-scale synchrotron emission by generating areliable all-sky spectral index map and temperature map at 45 MHz. Methods: Weuse our observations, the published all-sky map at 408 MHz, and abibliographical compilation to produce a map corrected for zero-level offsetand extragalactic contribution. Results: We present full sky maps of theGalactic emission at 45 MHz and the Galactic spectral index between 45 and 408MHz with an angular resolution of 5\degs. The spectral index varies between 2.1and 2.7, reaching values below 2.5 at low latitude because of thermal free-freeabsorption and its maximum in the zone next to the Northern Spur.