The Secular Decrease of the Crab Nebula at 927 and 151.5 MHz

Abstract

Long-term measurements have been carried out of the Crab Nebula radio emission flux density relative to Orion A at 927 MHz and relative to Cygnus A and Virgo A at 151.5 MHz. As a result the mean rates have been found of the secular change of the Crab Nebula radio emission flux density: $d_m(927MHz)=-(0.18\pm 0.10)$% year${}^{-1}$ (over the period 1977--2000), $d_m(151.5MHz)=-(0.32\pm 0.08)$% year${}^{-1}$ (over the period 1980--2003).

2 pages, 2 figures, poster report at Supernovae as Cosmological Lighthouses, 16-19 June 2004, Padua, Italy