Document Details Document Type : Article In Journal  Document Title : Orientation of galaxies in clusters Orientation of galaxies in clusters   Document Language : Arabic  Abstract : A detailed analysis of the geometry of galaxies in clusters has been undertaken in both two and three dimensional space. The procedure was applied to the three Abell clusters A1644, A548 E and A548 W. No significant alignment trend of galaxies in clusters confirmed in three dimensional space was found. This result is consistent with the mixed dark matter model MDM of galaxy formation. The result is also consistent with Peebles suggestion that protogalaxies acquired angular momentum from tidal torques exerted by their neighbours in the early universe. The amount of angular momentum predicted by this mechanism could be described by a single dimensionless papameter lambda approximate to 0.8. N-body experiments have shown that lambda has approximately normal distribution with mean value about 0.07 and with a standard deviation of about 0.03. From the analyic fit to flat rotation curves it is found that tidal torque can provide the observed angular momentum if the mean collapse factor is about 20 and the mean halo-to-disk mass ratio is of order 10. The MDM model does not predict any systematic relation between the tidal torques among the halos of galaxies and the large scale structures such as the clusters, superclusters of galaxies and giant voids in between. Further work in this area is still required.  Journal Name : ASTROPHYSICS AND SPACE SCIENCE  Volume : 283  Issue Number : 2  Publishing Year : 2003 AH   Added Date : Monday, June 23, 2008  Researchers Researcher Name (Arabic) Researcher Name (English) Researcher Type Dr Grade Email . Bukhari FA Researcher     . Cram LE Researcher     Back To Researches Page