Central mass accumulation in nuclear spirals

TL;DR

This paper uses high-resolution hydrodynamical simulations to show how nuclear spirals in galaxies can accumulate mass in their central regions, potentially leading to star formation and bulge development.

Contribution

It demonstrates the role of spiral shocks in transporting gas inward and forming high-density regions conducive to star formation in galaxy centers.

Findings

Gas accumulates in nuclear spirals due to spiral shocks.

High-density gas regions form downstream of shocks.

Conditions favor star formation and bulge growth.

Abstract

In central regions of non-axisymmetric galaxies high-resolution hydrodynamical simulations indicate spiral shocks, which are capable of transporting gas inwards. The efficiency of transport is lower at smaller radii, therefore instead of all gas dropping onto the galactic centre, a roughly uniform distribution of high-density gas develops in the gaseous nuclear spiral downstream from the shock, and the shear in gas is very low there. These are excellent conditions for star formation. This mechanism is likely to contribute to the process of (pseudo-) bulge formation.