Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.mrao.cam.ac.uk/~anthony/latex/Tello.ps Дата изменения: Sun May 21 20:56:18 2000 Дата индексирования: Tue Oct 2 02:18:58 2012 Кодировка: Поисковые слова: п п п п

A New Radio Continuum Survey of the Sky at 1465 MHz
between declinations 52 ф and +68 ф
C. Tello et al.
Instituto Nacional de Pesquisas Espaciais, Brazil
We have mapped the total sky brightness at 1465 MHz in two
adjacent 60 ф declination bands with the portable 5.5-m parabolic
re ector of the Galactic Emission Mapping (GEM) project, an on-
going international collaboration to survey the radio continuum of
the sky in decimeter and centimeter wavelengths. The observa-
tions were conducted from two locations, one in the USA and the
other in Brazil, using a novel instrumental approach to overcome
the well-known shortcomings of survey experiments. Our strategy
consists of a 1-rpm rotating dish to circularly scan the sky at 30 ф
from Zenith. The dish uses a rim-halo to re-direct the spillover
sidelobes of its backre helical feed toward the sky and the en-
tire assembly has been enclosed inside a wire mesh ground shield
in order to minimize and level out the contamination from the
ground. The diraction characteristics of this set-up have been
succesfully modelled and undesired systematic striping across the
observed bands has been carefully removed by a baseline propaga-
tion method which exploits the time-forward and time-backward
intersection of the circular scanning technique. The nal map dis-
plays nearly 300 hours of our best quality data with a 6 ф resolution
and a sensitivity of 20 mK.
(Co-authors: T. Villela/Brazil, G.F. Smoot/USA, S. Tor-
res/Colombia, M. Bersanelli/Italy.)
1