Mass inflow rate in the Central Molecular Zone: observational determination and evidence of episodic accretion

Mattia Sormani

Poster -- Galactic scale ISM and star formation

It is well known that the Galactic bar drives a gas inflow into the Central Molecular Zone, which fuels star formation. This inflow happens mostly through two symmetrical dust-lanes, similar to those often seen in external barred galaxies. We use the fact that the Milky Way dust-lanes have been previously identified in the 12CO data cubes and a simple geometrical model to derive the first observational determination of the mass inflow rate in the Central Molecular Zone. We find that the time-averaged inflow rate along the near-side dust lane is $1.1^{+0.6}_{-0.3}\, \rm M_\odot yr^{-1}$ and along the far-side dust lane is $1.5^{+0.7}_{-0.4}\, \rm M_\odot yr^{-1}$, which gives a total inflow of $2.6^{+1.3}_{-0.7}\, \rm M_\odot yr^{-1}$. We also provide the time series of the inflow rate $\dot{M}$ for the next few Myr. The latter shows that the inflow rate is variable with time, supporting a scenario of episodic accretion onto the Central Molecular Zone.