„Prezentacja 20/20” – uniwersytecka inicjatywa dla maturzystów

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simole model for DLA

Consider the following model: we have N parallel sticks of integer length, and at integer moments exactly one stick grows by 1, with the probability of k-th stick growing proportional to a fixed power 1'1of its length, properly normalized. Equivalently, we consider sequences of points of the first quadrant of Rn such that on each step exactly one of the coordinates of the point gets incremented...

A DLA model for Turbulence

A connection between fractal dimensions of ”turbulent facets”, and fractal dimensions in DLA is shown.

Dust obscuration of DLA galaxies

We show that the extinction of quasar absorbers increases exponentially with the logarithmic column density of any volatile metal (e.g. zinc), with a charateristic turning point above which the quasars are severely dimmed. We derive the relation between extinction, HI column density (NHI), metallicity (Z ≡ NZnII/NHI) and fraction of iron in dust [fFe(Z)] in Damped Lyman α (DLA) systems. We use ...

Conformal approach to cylindrical DLA

We extend the conformal mapping approach elaborated for the radial Diffusion Limited Aggregation model (DLA) to the cylindrical geometry. We introduce in particular a complex function which allows to grow a cylindrical cluster using as intermediate step a radial aggregate. The grown aggregate exhibits the same selfaffine features of the original cylindrical DLA. The specific choice of the trans...