We present new NH _ { 3 } ( 1,1 ) , ( 2,2 ) , and ( 4,4 ) observations from the Karl G. Jansky Very Large Array ( VLA ) compiled with work in the literature to explore the range of conditions observed in young , massive star-forming regions .
To sample the effects of evolution independent from those of distance/resolution , abundance , and large-scale environment , we compare clumps in different evolutionary stages within a single Infrared Dark Cloud ( IRDC ) , G32.02+0.06 .
We find that the early stages of clustered star formation are characterized by dense , parsec-scale filamentary structures interspersed with complexes of dense cores ( < 0.1 pc cores clustered in complexes separated by \sim 1 pc ) with masses from about 10 to 100 M _ { \odot } .
The most quiescent core is the most extended while the star forming cores are denser and more compact , showing very similar column density structure before and shortly after the onset of massive star formation , with peak surface densities \Sigma \gtrsim 1 g cm ^ { -2 } .
Quiescent cores and filaments show smoothly varying temperatures from 10-20 K , rising to over 40 K in star-forming cores .
We calculate virial parameters for 16 cores and find that the level of support provided by turbulence is generally insufficient to support them against gravitational collapse ( \langle \alpha _ { vir } \rangle \sim 0.6 ) .
The star-forming filaments show smooth velocity fields , punctuated by discontinuities at the sites of active star formation .
We discuss the Massive Molecular Filament ( MMF ; M \sim 10 ^ { 5 } M _ { \odot } , length > 60 pc ) hosting the IRDC , hypothesizing that it may have been shaped by previous generations of massive stars .