GMCs scaling relations: role of the cloud definition
  We investigate physical properties of molecular clouds in disc galaxies with
different morphology: a galaxy without prominent structure, a spiral barred
galaxy and a galaxy with flocculent structure. Our $N$-body/hydrodynamical
simulations take into account non-equilibrium H$_2$ and CO chemical kinetics,
self-gravity, star formation and feedback processes. For the simulated galaxies
the scaling relations of giant molecular clouds or so called Larson's relations
are studied for two types of a cloud definition (or extraction methods): the
first one is based on total column density position-position (PP) datasets and
the second one is indicated by the CO~(1-0) line emission used
position-position-velocity (PPV) data. We find that the cloud populations
obtained by using both cloud extraction methods generally have similar physical
parameters. Except that for the CO data the mass spectrum of clouds has a tail
with low-massive objects $M\sim 10^3-10^4$~\Msun. Varying column density
threshold the power-law indices in the scaling relations are significantly
changed. In contrast, the relations are invariant to CO brightness temperature
threshold. Finally, we find that the mass spectra of clouds for the PPV data
are almost insensitive to the galactic morphology, whereas the spectra for the
PP data demonstrate significant variations.
