Manolis Plionis
Monthly Notices of the Royal Astronomical Society, Volume 234, Issue 2, September 1988, Pages 401–416
Publication year: 1988

Summary 

Large-scale number-count anisotropies are present in the Shane & Wirtanen galaxy catalogue. These anisotropies add up to a dipole pointing within 9°−34° of the microwave background radiation dipole, consistent with the dipoles of a shallower optical and of the IRAS galaxy catalogues. The dipole amplitude is ∼4.7±1.3 per cent. The high surface density regions show a dipole anisotropy pointing roughly towards the direction of the recently reported large-scale streaming motion of a sample of elliptical galaxies, while the low density regions appear to have a dipole distribution pointing roughly towards the Local Group motion with respect to the frame defined by these elliptical galaxies. These anisotropies appear to be caused neither by systematic and random errors nor by galactic or atmospheric absorption.