  The first hydrostatic core (FHSC) is the first stable object to form in
simulations of star formation. This stage has yet to be observed definitively,
although several candidate FHSCs have been reported. We have produced synthetic
spectral energy distributions (SEDs) from 3D hydrodynamical simulations of
pre-stellar cores undergoing gravitational collapse for a variety of initial
conditions. Variations in the initial rotation rate, radius and mass lead to
differences in the location of the SED peak and far-infrared flux. Secondly, we
attempt to fit the SEDs of five FHSC candidates from the literature and five
newly identified FHSC candidates located in the Serpens South molecular cloud
with simulated SEDs. The most promising FHSC candidates are fitted by a limited
number of model SEDs with consistent properties, which suggests the SED can be
useful for placing constraints on the age and rotation rate of the source. The
sources we consider most likely to be in FHSC phase are B1-bN, CB17-MMS,
Aqu-MM1 and Serpens South candidate K242. We were unable to fit SerpS-MM22,
Per-Bolo 58 and Chamaeleon-MMS1 with reasonable parameters, which indicates
that they are likely to be more evolved.
