Recognition and characterization of hierarchical interstellar structure. I - Correlation function
P. Houlahan, J. Scalo;
ApJS, 1990, 72, 133
ABSTRACT:The problem of the quantitative description of multiscale structure in interstellar cloud complexes and gravitational collapse
calculations is considered, emphasizing the recognition and characterization of
hierarchical fragmentation structure.
The response of the two-point correlation
function to a variety of analytical models for density structure is discussed
for simple clustering of pointlike clouds to more complex models
involving clouds with a distribution of sizes and densities and hierarchical
substructure.
By expressing the density distribution as the superposition of
individual clouds, it is shown that the correlation function generates two types
of terms: those involving each cloud's density convolved with itself and
those involving pairs of different clouds.
Major distortion of the
correlation function are introduced by the presence of any image features with size
scales a significant fraction of the image size.
Ils ont test\'e la ACR sur une vari\'et\'e d'objets simul\'es. Le comportement de
l'ACR est compl\`etement domin\'e par les structures dans l'image (ex. gradient).
L'information sur l'autosimilarit\'e des structures est alors compl\`etement
noy\'ee. {\bf Notons n\'eanmoins que l'\'etude ici faite est sur des champ de DENSIT\'E}.
KEYWORDS: astronomical models, gravitational collapse, interstellar matter, molecular clouds, star formation, computational astrophysics, correlation, hierarchies, power spectra
PERSOKEY:turbulence, ,
CODE: houlahan90