Title: "Characterization of molecular emission lines detected in three local star-forming galaxies 
using far-IR Herschel/HIFI and sub-mm APEX data"

Abstract:
We present the results from far-IR Herschel/HIFI (480 to 1910 GHz) and sub-mm APEX 
observations (200-360 GHz) of three local starburst galaxies: NGC 4945, NGC 253 and Arp 220. 
We detected CO, 13^CO, CI and CH in emission as well as some dense gas tracers, such as 
HNC, HCN, HCO+, CS. We derived the main physical parameters of the galaxies (e.g., column 
density, excitation temperature and local standard of rest velocity) by applying a Local 
Thermodynamic Equilibrium (LTE) analysis to these molecular lines. A Large Velocity Gradient 
(LVG) analysis indicates that the volume gas density of these galaxies is about 10^6 cm-3. The 
unprecedented high sensitivity and angular resolution of ALMA will allow to spatially resolve (on 
both pc and kpc scales) the gas properties (e.g., temperatures, densities, isotopic ratios) as 
key parameters to explore the relationship between star formation, gas density and also the gas 
kinematics, in comparison with other tracers, like the atomic and ionized gas.