We performed ^ { 12 } CO ( 1 – 0 ) , ^ { 13 } CO ( 1 – 0 ) , and HCN ( 1 – 0 ) interferometric observations of the central region ( about 450 pc in radius ) of M82 with the Nobeyama Millimeter Array , and have successfully imaged a molecular superbubble and spurs .
The center of the superbubble is clearly shifted from the nucleus by 140 pc .
This position is close to that of the massive black hole ( BH ) of \gtrsim 460 M _ { \odot } and the 2.2 \mu m secondary peak ( a luminous supergiant dominated cluster ) , which strongly suggests that these objects may be related to the formation of the superbubble .
Consideration of star formation in the cluster based on the infrared data indicates that ( 1 ) energy release from supernovae can account for the kinetic energy of the superbubble , ( 2 ) the total mass of stellar-mass BHs available for building-up the massive BH may be much higher than 460 M _ { \odot } , and ( 3 ) it is possible to form the middle-mass BH of 10 ^ { 2 } -10 ^ { 3 } M _ { \odot } within the timescale of the superbubble .
We suggest that the massive BH was produced and is growing in the intense starburst region .