  The observational counterparts of theoretically predicted first hydrostatic
cores (FHSC) have been searched for in the interstellar medium for nearly two
decades now. Distinguishing them from other types of more evolved but still
embedded objects remains a challenge because these objects have a short
lifetime, are small, and embedded in a dense cocoon. One possible lead to
finding them is the characterization of the outflows that are launched by these
objects. We observed the L1451-mm FHSC candidate with the NOEMA interferometer
in order to study the emission of several molecules. A nonlocal thermodynamic
equilibrium analysis of the CH$_3$OH detected lines was performed to retrieve
the physical conditions of the emitting region around the central source,
together with the CH$_3$OH, SiO, CS, and H$_2$CO column densities. Of the
targeted molecules, we detected lines of c-C$_3$H$_2$, CH$_3$OH, CS, C$^{34}$S,
SO, DCN, DCO$^+$, H$_2$CO, HC$_3$N, HDCO, and SiO. One of the methanol lines
appears to be a maser line. The detection of this class I maser and the SiO
line in L1451-mm support the presence of a low-velocity and compact outflow.
The excitation conditions of the thermal lines of methanol are also compatible
with shocks (H$_2$ density of $\sim 3\times 10^6$~cm$^{-3}$ and a temperature
higher than 40~K). Although these low-velocity outflows are theoretically
predicted by some models of FHSC, these models also predict the shock
temperature to be below 20~K, that is, not evaporating methanol. In addition,
the predicted velocities would not erode the grains and release silicon in the
gas phase. We therefore conclude that these new observations favor the
hypothesis that L1451-mm would be at a very early protostellar stage, launching
an outflow nearly on the plane of the sky with a higher velocity than is
observed.
