SIMBAD references

1994A&A...288...30G - Astronomy and Astrophysics, volume 288, 30-42 (1994/8-1)

Analysis of the kinematical behaviour of the near universe II. Voids.

GOICOECHEA L.J.

Abstract (from CDS):

The dynamical effect generated by underdense regions in the local universe is investigated by means of the kinematical data of elliptical galaxies. The sample is sensitive to six QDOT-IRAS voids at z ≤4000 km/s. If we assume the relative masses (m = M/MVirgo) and the velocity indexes of large clusters predicted from QDOT-IRAS galaxies, and reasonable models for the peculiar velocity field around the bubbles, we obtain an important outflow velocity (≥100 km/s) up to galaxy-void distances of ≃25 h–1Mpc. The existence of the six mentioned voids leads to an excellent velocity dispersion for some subsamples of ellipticals (also, the likelihood is significatively increased for all the subsamples). As the voids are placed among two very prominent accumulations of matter (Great Attractor and Perseus-Pisces), a part of the dynamical tail of the bubbles may be due to an underestimation of the mass of both large superclusters. To investigate this possibility, we have analyzed two pictures including free superclusters (either the velocity index and the masses are free parameters, or the masses appear as the only free parameters): only superclusters and superclusters + voids. The new solutions with free superclusters + voids have a likelihood greater than the previously quoted ones (QDOT-IRAS traced superclusters + voids). Now, the infall velocities towards the Great Attractor (Pavo and North Centaurus) and Perseus-Pisces are larger than those inferred from the QDOT-IRAS survey, and the push (at the surface) from a typical void is consistent with {OMEGA}=1 and a reasonable value of its radius (5 h–1-10 h–1Mpc). Moreover, by using large clusters without constraints (only superclusters or superclusters + voids) and some selected subsamples, the solutions cannot account for the MBR dipole, i.e., a Local Anomaly is necessary to explain the observed motion of the Local Group. We have seen a good correlation between the direction of the residual velocities predicted by the solutions and the direction of our infall towards the very local luminous matter.

Abstract Copyright:

Journal keyword(s): cosmology: large-scale structure of Universe - galaxies: clustering - galaxies: distances and redshifts

Simbad objects: 7

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