Formation of Galactic Prominence in the Galactic Central Region

Abstract

Abstract We carried out 2.5-dimensional resistive MHD simulations to study the formation mechanism of molecular loops observed by Fukui et al. in the Galactic central region. Since it is hard to form molecular loops by lifting up dense molecular gas, we study the formation mechanism of molecular gas in rising magnetic arcades. This model is based on the in situ formation model of solar prominences, in which prominences are formed by cooling instability in helical magnetic flux ropes formed by imposing converging and shearing motion at footpoints of the magnetic arch anchored to the solar surface. We extended this model to Galactic center scale (a few hundreds of parsecs). Numerical results indicate that magnetic reconnection taking place in the current sheet that formed inside the rising magnetic arcade creates dense blobs confined by the rising helical magnetic flux ropes. Thermal instability taking place in the flux ropes forms dense molecular filaments floating at high Galactic latitude. The mass of the filament increases with time and can exceed 10 5 M ⊙ .