ALMA Detection of Bipolar Outflows: Evidence for Low Mass Star Formation within 1pc of Sgr A*

TL;DR

Deep ALMA observations reveal 11 bipolar outflows near Sgr A*, providing evidence for ongoing low-mass star formation within 1 parsec of the supermassive black hole, challenging previous assumptions about star formation in such extreme environments.

Contribution

First detection of bipolar outflows indicating low-mass star formation within 1pc of Sgr A* using high-resolution ALMA data.

Findings

11 bipolar outflows detected near Sgr A*

Estimated star formation rate of ~5×10^{-4} solar masses per year

Star formation activity could influence the stellar mass in the Galactic center

Abstract

We report the discovery of 11 bipolar outflows within a projected distance of 1pc from Sgr A* based on deep ALMA observations of $^{13}$CO, H30$\alpha$ and SiO (5-4) lines with sub-arcsecond and $\sim1.3$ km/s, resolutions. These unambiguous signatures of young protostars manifest as approaching and receding lobes of dense gas swept up by the jets created during the formation and early evolution of stars. The lobe masses and momentum transfer rates are consistent with young protostellar outflows found throughout the disk of the Galaxy. The mean dynamical age of the outflow population is estimated to be $6.5^{+8.1}_{-3.6}\times10^3$ years. The rate of star formation is $\sim5\times10^{-4}$\msol\,yr$^{-1}$ assuming a mean stellar mass of $\sim0.3$ \msol. This discovery provides evidence that star formation is taking place within clouds surprisingly close to Sgr A*, perhaps due to events that compress the host cloud, creating condensations with sufficient self-gravity to resist tidal disruption by Sgr A*. Low-mass star formation over the past few billion years at this level would contribute significantly to the stellar mass budget in the central few pc of the Galaxy. The presence of many dense clumps of molecular material within 1pc of Sgr A* suggests that star formation could take place in the immediate vicinity of supermassive black holes in the nuclei of external galaxies