Water maser detections toward 70 $μ$m infrared dark clumps at early star formation stage

Water masers provided powerful probes of shocked gas and protostellar activity during the early stages of star formation. Using VLA K-band observations of the 22 GHz water line, we report the first detections of water masers toward dense cores in five 70 $μ$m infrared dark clumps, providing evidence