Kinematics of a young low-mass star forming core: Understanding the
  evolutionary state of the First Core Candidate L1451-mm
  We use 3mm multi-line and continuum CARMA observations towards the first
hydrostatic core (FHSC) candidate L1451-mm to characterize the envelope
kinematics at 1000 AU scales and investigate its evolutionary state. We detect
evidence of infall and rotation in the N2H+(1-0), NH2D(1(1,1)-1(0,1)) and
HCN(1-0) molecular lines. We compare the position velocity diagram of the NH2D
line with a simple kinematic model and find that it is consistent with an
envelope that is both infalling and rotating while conserving angular momentum
around a central mass of about 0.06 Msun. The N2H+(1-0) LTE mass of the
envelope along with the inferred infall velocity leads to a mass infall rate of
approximately 6e-6 Msun/yr, implying a young age of 10,000 years for this FHSC
candidate. Assuming that the accretion onto the central object is the same as
the infall rate we obtain that the minimum source size is 1.5-5 AU consistent
with the size expected for a first core. We do not see any evidence of outflow
motions or signs of outflow-envelope interaction at scales > 2000 AU. This is
consistent with previous observations that revealed a very compact outflow
(<500 AU). We conclude that L1451-mm is indeed at a very early stage of
evolution, either a first core or an extremely young Class 0 protostar. Our
results provide strong evidence that L1451-mm is the best candidate for being a
bonafide first core.
