Low-Mass Star-Forming Cores in the GF9 Filament

We carried out an unbiased mapping survey of dense molecular cloud cores traced by the NH3 (1,1) and (2,2) inversion lines in the GF 9 filament, which contains an extremely young low-mass protostar, GF 9-2 (2006, ApJ, 653, 1369). The survey was conducted using the Nobeyama 45m telescope over a region of ~1.5° × 1° with an angular resolution of 73". The large-scale map revealed that the filament contains at least 7 dense cores, as well as 3 possible ones, located at regular intervals of ~0.9 pc. Our analysis shows that these cores have kinetic temperatures of ≾10K and LTE-masses of 1.8–8.2M☉, which makes them typical sites of low-mass star formation. All of the identified cores are likely to be gravitationally unstable, because their LTE-masses are larger than their virial masses. Since the LTE-masses and separations of the cores are consistent with the Jeans masses and lengths, respectively, for the low-density ambient gas, we argue that the identified cores formed via the gravitational fragmentation of the natal filamentary cloud