Evidence for supernova feedback sustaining gas turbulence in nearby star-forming galaxies by C. Bacchini et al. on Wednesday 30 November

HI and CO observations indicate that the cold gas in galaxies is very

turbulent. However, the turbulent energy is expected to be quickly dissipated,

implying that some energy source is needed to explain the observations. The

nature of such turbulence was long unclear, as even the main candidate,

supernova (SN) feedback, seemed insufficient. Other mechanisms have been

proposed, but without reaching a general consensus. The key novelty of our work

is considering that the gas disc thickness and flaring increase the dissipation

timescale of turbulence, thus reducing the energy injection rate required to

sustain it. In excellent agreement with the theoretical expectations, we found

that the fraction of the SN energy (a.k.a. SN coupling efficiency) needed to

maintain the cold gas turbulence is $\sim 1$%, solving a long-standing

conundrum.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16540v1