Spectra from the shocked nebulae revealing turbulence near the Galactic Centre

TL;DR

This paper analyzes spectra from nebulae near the Galactic Centre to reveal turbulence caused by shocks, showing distinct physical conditions compared to starburst galaxies and AGN.

Contribution

It provides a detailed comparison of nebular spectra near the Galactic Centre with active galaxies, highlighting turbulence and fragmentation due to shocks.

Findings

Physical conditions differ from starburst galaxies and AGN.

Nebulae have low gas velocities, densities, and photoionization fluxes.

Evidence of shock-generated turbulence and matter fragmentation.

Abstract

The spectra emitted from clouds near the Galactic Centre are investigated calculating the UV-optical-IR lines using the physical parameters and the element abundances constrained by the fit of mid-IR observations. The characteristic line ratios are compared with those observed in active galaxies. We have found that the physical conditions in the nebulae near the GC are different from those of starburst galaxies and AGN, namely, gas velocities and densities as well as the photoionization fluxes are relatively low. The geometrical thickness of the emitting nebulae is particularly small suggesting that matter is strongly fragmented by instabilities leading to an underlying shock-generated turbulence.