ACES: The Magnetic Field in Large Filaments in the Galactic Center

TL;DR

This study investigates the magnetic field orientations in dense filaments of the Galactic Center's Central Molecular Zone, revealing complex magnetic environments and the influence of turbulence, with implications for filament support against collapse.

Contribution

It provides the first detailed comparison of magnetic field orientations in GC filaments with synthetic MHD models, highlighting the varied dominant formation mechanisms.

Findings

Magnetic orientations vary widely, indicating complex environments.

Filaments are in magnetically dominated environments supporting against collapse.

Some filaments resemble Galactic Disk 'bones' in structure and formation.

Abstract

The Galactic Center (GC) is an extreme region of the Milky Way that is host to a complex set of thermal and non-thermal structures. In particular, the GC contains high-density gas and dust that is collectively referred to as the Central Molecular Zone (CMZ). In this work, we study a subset of HNCO filaments identified in band 3 ALMA observations of the GC obtained by the ALMA CMZ Exploration Survey (ACES) that are comparable to high density filaments identified in the Galactic Disk. We compare the orientation of the magnetic field derived from 214 um SOFIA and 850 um JCMT observations with the filament orientation to determine which mechanisms dominate the formation of these filaments. We observe a large range of magnetic orientations in our observed filaments indicating the complex environments the filaments are located in. We also compare the observational results to synthetic data sets created using an MHD model of the GC. Our analysis reveals that the dominant mechanisms local to the HNCO filaments vary throughout the GC with some filaments being dominated by supersonic turbulence and others by subsonic turbulence. The comparison to synthetic observations indicates that the observed filaments are in magnetically dominated environments that could be supporting these filaments against collapse. Our results on the CMZ filaments are also compared to results obtained on similar filaments located in the Galactic Disk, and we find that the filaments studied here are possible CMZ analogs to the dense filamentary "bones" observed previously in the Galactic Disk.