SIMBAD references

We used the Nobeyama 45 m radio telescope to reveal spatial distributions of CCS and HC₃ N in L1147, one of the carbon-chain producing region (CCPR) candidates, where carbon-chain molecules are dominant rather than NH₃. We found that three cores (two CCS cores and one HC₃N core), which are away from a very low luminosity object (a source that may turn into a sub-stellar mass brown dwarf), exist along the NE-SW filament traced by the 850 µm dust continuum. The column densities of CCS are 3-7x10¹²/cm2 and those of HC₃N are 2-6x10¹²/cm2, respectively, much lower than those previously reported toward other CCPRs. We also found that two CCS peaks are displaced from the peaks of HC₃N. In order to interpret such interleaved distributions, we conducted chemical reaction network simulations and found that slightly different gas densities could lead to large variation of the CCS-to-HC₃N ratio in the early phase of dark cloud evolution. Such a chemical "variation" may be seen in other CCPRs. Finally, we were able to confirm that the L1147 filament can be regarded as a CCPR.