Mathematics – Probability
Scientific paper
Oct 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...434...24b&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 434, no. 1, p. 24-36
Mathematics
Probability
19
Astronomical Models, Cosmology, Galactic Evolution, Galactic Mass, Galactic Structure, Gravitational Collapse, Gravitational Fields, Universe, Analytic Functions, Poisson Equation, Red Shift, Velocity
Scientific paper
Gravitational instability theory provides our physical understanding of how structure forms in the universe. The growth of the velocity field leads to the formation of filaments or chains of galaxies, which we shall term large-scale structure (LSS). As galaxies are not continuous tracers of structure, this leads us to introduce the concept of a 'broken network structure' as a model of lSS. Furthermore, modulation by the gravitational potential results in 'voids' containing regions of positive potential with boundaries of sheets or 'walls' of rich filaments, which we shall identify as superlarge-scale structure (SLSS), with then a 'broken cellular structure' as a model of SLSS. Observationally, large galaxy redshift surveys corroborate the theory by their striking in the universe are simply the surface density of filaments, that is, the number intersecting unit area, and the size of 'cells'. We introduce here a new simple method of analysis to measure these directly. As this present method deals with pencil beam surveys, instead of attempting to measure the cell size we measure the linear density of 'sheets' that is, the number intersecting a line of unit length. As the more frequent elements of SLSS are probable superclusters and rich filaments of galaxies, we shall simply term an element of SLSS a 'supercluster'; to a pencil beam beam survey such elements appear sheetlike. We test out the method using simple numerical simulations of such structure, as well as on simulations of Poisson and the geometric Soneira-Peebles hierarchical models, which clearly have no such structure. In an exploratory investigation of the method with real data, we apply it to the presently available deep pencil beam galaxy redshift surveys. We find for the mean surface density of filaments sigmaf approximately = 0.45 x 10-2 h2/sq Mpc, which corresponds to a mean separation of Df approximately = 14/h Mpc, corresponding to a mean distance between superclusters of Ds approximately = 50/h Mpc. For the very deep surveys, we find instead Ds2 approximately = 130/h Mpc. If we take into account the low probability of approximately = 0.4 for a 'sheet' to be detected in these surveys, the result also corresponds to a supercluster scale of approximately = 50 /h Mpc. Finally, we consider the theoretical interpretation of these scales and discuss some of the possible observational problems and their future resolution.
Buryak Olga E.
Doroshkevich Andrei G.
Fong Richard
No associations
LandOfFree
Measurement of large- and superlarge-scale structures of the universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Measurement of large- and superlarge-scale structures of the universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Measurement of large- and superlarge-scale structures of the universe will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1070395