Magnetic support of the optical emission line filaments in NGC 1275

TL;DR

This paper presents evidence that magnetic fields stabilize the long, thin emission-line filaments in NGC 1275, enabling cold gas accumulation and influencing galaxy feedback processes.

Contribution

It provides new high-resolution observations showing magnetic support of filaments, clarifying their stability mechanism in the galaxy's environment.

Findings

Magnetic fields in filaments are in pressure balance with surrounding gas.

Threads can extend over 6 kpc while being only 70 pc wide.

Magnetic support delays star formation in the filaments.

Abstract

The giant elliptical galaxy NGC 1275, at the centre of the Perseus cluster, is surrounded by a well-known giant nebulosity of emission-line filaments, which are plausibly about >10^8 yr old. The filaments are dragged out from the centre of the galaxy by the radio bubbles rising buoyantly in the hot intracluster gas before later falling back. They act as dramatic markers of the feedback process by which energy is transferred from the central massive black hole to the surrounding gas. The mechanism by which the filaments are stabilized against tidal shear and dissipation into the surrounding 4x10^7 K gas has been unclear. Here we report new observations that resolve thread-like structures in the filaments. Some threads extend over 6 kpc, yet are only 70 pc wide. We conclude that magnetic fields in the threads, in pressure balance with the surrounding gas, stabilize the filaments, so allowing a large mass of cold gas to accumulate and delay star formation.