Crawling the cosmic network: Exploring the morphology of structure in the galaxy distribution

Nicholas A. Bond, Michael A. Strauss, Renyue Cen

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Although coherent large-scale structures such as filaments and walls are apparent to the eye in galaxy redshift surveys, they have so far proven difficult to characterize with computer algorithms. This paper presents a procedure that uses the eigenvalues and eigenvectors of the Hessian matrix of the galaxy density field to characterize the morphology of large-scale structure. By analysing the smoothed density field and its Hessian matrix, we can determine the types of structure - walls, filaments or clumps - that dominate the large-scale distribution of galaxies as a function of scale. We have run the algorithm on mock galaxy distributions in a Λcold dark matter cosmological N-body simulation and the observed galaxy distributions in the Sloan Digital Sky Survey. The morphology of structure is similar between the two catalogues, both being filament-dominated on 10-20 h-1 Mpc smoothing scales and clump-dominated on 5 h-1 Mpc scales. There is evidence for walls in both distributions, but walls are not the dominant structures on scales smaller than ∼ 25 h-1 Mpc. Analysis of the simulation suggests that, on a given comoving smoothing scale, structures evolve with time from walls to filaments to clumps, where those found on smaller smoothing scales are further in this progression at a given time.

Original languageEnglish (US)
Pages (from-to)1609-1628
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Aug 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Cosmology: observations
  • Large-scale structure of Universe
  • Methods: data analysis
  • Surveys


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