  A quasi-resonant laser induces a long-range attractive force within a cloud
of cold atoms. We take advantage of this force to build in the laboratory a
system of particles with a one-dimensional gravitational-like interaction, at a
fluid level of modeling. We give experimental evidences of such an interaction
in a cold Strontium gas, studying the density profile of the cloud, its size as
a function of the number of atoms, and its breathing oscillations.
