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تسجيل مستخدم جديدInvestigations of the Local Supercluster Velocity Field III. Tracing the backside infall with distance moduli from the direct Tully-Fisher relation
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We have extended the discussion of Paper II (Ekholm et al. 1999) to cover also the backside of the Local Supercluster (LSC) by using 96 galaxies within Theta<30 deg from the adopted centre of LSC and with distance moduli from the direct B-band Tully-Fisher relation. In order to minimize the influence of the Malmquist bias we required log V_max>2.1 and sigma_{B_T}<0.2 mag. We found out that if R_Virgo<20 Mpc this sample fails to follow the expected dynamical pattern from the Tolman-Bondi (TB) model. When we compared our results with the Virgo core galaxies given by Federspiel et al. (1998) we were able to constrain the distance to Virgo: R_Virgo=20-24 Mpc. When analyzing the TB-behaviour of the sample as seen from the origin of the metric as well as that with distances from the extragalactic Cepheid PL-relation we found additional support to the estimate R_Virgo=21 Mpc given in Paper II. Using a two-component mass-model we found a Virgo mass estimate M_Virgo= (1.5-2)M_virial, where M_virial=9.375.10^14M_sun for R_Virgo=21 Mpc. This estimate agrees with the conclusion in Paper I (Teerikorpi et al. 1992). Our results indicate that the density distribution of luminous matter is shallower than that of the total gravitating matter when q_0<=0.5. The preferred exponent in the density power law, alphaapprox2.5, agrees with recent theoretical work on the universal density profile of dark matter clustering in an Einstein-deSitter universe (Tittley & Couchman 1999).
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