GREAT ATTRACTOR-LIKE FLUCTUATIONS - OBSERVATIONAL MANIFESTATIONS AND THEORETICAL CONSTRAINTS

The possibility of the explanation of the large-scale peculiar velocit y field around the Local Group (LG) as a result of gravitational actio n of high- amplitude Great Attractor-like fluctuations of a random Gau ssian density field in the Friedmann flat cosmological models with col d, hot and mixed dark matter is investigated. Under the assumption tha t the observable peculiar velocity field is a result of joint action o f Great Attractor (GA), Shapley Concentration (ShC) and the large-scal e bulk flow component (besides infall to Virgo and the Local Anomaly, which are of smaller scale) the necessary parameters of peak-precursor s of GA and ShC are evaluated, their evolution from early linear stage s to present-day is simulated and conditions of realisation of such pe aks in different cosmological models are analysed. It is shown, that i n case of predomination of one source of velocity field - GA - the cor responding peak-precursor has the overdensity delta = (1 divided by 2) /(z+1) and characteristic half-amplitude radius R(delta/2) = (20 divid ed by 25)/(z + 1)h(-1) Mpc for redshifts z >> 1, but the concentration of such peaks is very poor in all models considered. Besides the pecu liar velocity field, such peaks are able to generate hot and cold spot s on the cosmic microwave background sky which are accessible to regis tration by existing techniques. Some of these peaks may show violent d ynamical relaxation in central regions. It is shown, that the possibil ity of the generation of the large-scale velocity component with U-LG = 535 kms-land even with U-LG = 300 km s(-1) via gravitational action of ShC will be insignificant. From the models considered, the preferab le one is joint action of the smaller GA, which contributes a peculiar velocity of the LG U-LG approximate to 235 km s(-1), and the large-sc ale bulk flow component with amplitude of approximate to 300 km s(-1).