Magnetic fields and gas flows around circumnuclear starbursts

TL;DR

This paper discusses how strong magnetic fields in circumnuclear starbursts influence gas inflow and outflows, potentially fueling active galactic nuclei and linking star formation with black hole accretion.

Contribution

It presents observational evidence of magnetic fields in starburst galaxies and explores their role in gas dynamics and galaxy evolution.

Findings

Magnetic fields of >= 50-100 muG in circumnuclear regions.

Magnetic stress drives gas inflow towards galaxy centers.

Detection of large-scale helical magnetic fields in outflows.

Abstract

Radio continuum observations of barred galaxies revealed strong magnetic fields of >= 50-100 muG in the circumnuclear starbursts. Such fields are dynamically important and give rise to magnetic stress that causes inflow of gas towards the center at a rate of several solar masses per year, possibly along the spiral field seen in radio polarization and as optical dust lanes. This may solve the long-standing question of how to feed active nuclei, and explain the relation between the bolometric luminosity of AGN nuclei and the star-formation rate of their hosts. The strong magnetic fields generated in young galaxies may serve as the link between star formation and accretion onto supermassive black holes. -- Magnetic fields of >= 160 muG strength were measured in the central region of the almost edge-on starburst galaxy NGC 253. Four filaments emerging from the inner disk delineate the boundaries of the central outflow cone of hot gas. Strong Faraday rotation of the polarized emission from the background disk indicates a large-scale helical field in the outflow walls.