LELUYA  the Next Generation Radiative Transfer Modeling
Whenever energy in the form of radiation travels through a medium, it is absorbed, scattered, and reemitted. We study the medium by
observing such reprocessed energy. The medium can be a dust cloud around a star or in a galaxy, the Earth's atmosphere,
a human body, etc. Not surprisingly, numerical models of radiative transfer appeared together with the first computers.
Since then, the algorithms have evolved and been able to calculate exact solutions to onedimensional geometrical configurations
(sphere or slab). However, there is still no a robust exact solver for multidimensional configurations.
Current state of the art computer codes can handle it only by Monte
Carlo techniques on simplified numerical grids, often with limited
precision, or by applying approximate methods and trivial configurations
to simplify the problem.
Astronomical observations of objects deeply imbedded in dust cannot be studied
without an exact solution of the multidimensional
radiative transfer problem. LELUYA is the first code capable of solving exactly an arbitrary axially symmetric
multigrain dust distribution around a heating source. A newly developed parallel algorithm automatically traces the dust density
and optical depth gradients, creating the optimal adaptive grid, which is highly unstructured and triangular. Different grids are
created this way for different wavelengths to accommodate the spectral variation of dust opacity. The radiative transfer problem,
including dust absorption, emission and scattering, is solved exactly.


The first applications, currently underway, already yield results that other codes are not able to achieve. For example, the image
of an evolved star seemed to require an unphysical binary system. LELUYA shows that this is an artifact of certain 2D dust geometry
around a single star, which includes a nonspherical dust cavity. Such a cavity cannot be found automatically and self consistently
by any other radiative transfer code. Another popular application is in young stellar objects, where LELUYA provides the first tool
capable of exact handling of nonspherical geometries, crucial for understanding configurations such as flared disks.
(Apr 18, 2002)
What does LELUYA mean?
The name Leluya was suggested by Lidija Bajuk
(scena.hgu.hr/lidijabajuk).
Explanation of its meaning you can find here:
www.leluya.org/mythology/Leluya.html
What does the LELUYA's logo represent?
Creature shown on the logo is a "firefly man". Very little is known
about them, except that they can "catch" light and "eat" it. When they
are very hungry, they sometimes enter a room and fly around a light bulb
eating the light so fast that the room becomes dark.
The logo was designed by Marko Cavka (zenmaster@hrvatska.com).

