English

The JCMT BISTRO Survey: Magnetic Fields Align with Orbital Structure in the Galactic Center

Astrophysics of Galaxies 2025-03-05 v2

Abstract

We present the magnetic field in the dense material of the Central Molecular Zone (CMZ) of the Milky Way, traced in 850 μ\mum polarized dust emission as part of the James Clerk Maxwell Telescope (JCMT) B-fields In STar-forming Region Observations (BISTRO) Survey. We observe a highly ordered magnetic field across the CMZ between Sgr B2 and Sgr C, which is strongly preferentially aligned with the orbital gas flows within the clouds of the CMZ. We find that the observed relative orientations are non-random at a >>99% confidence level and are consistent with models in which the magnetic field vectors are aligned within 30o^{o} to the gas flows in 3D. The deviations from aligned magnetic fields are most prominent at positive Galactic longitudes, where the CMZ clouds are more massive, denser, and more actively forming stars. Our observed strongly preferentially parallel magnetic field morphology leads us to hypothesize that in the absence of star formation, the magnetic field in the CMZ is entrained in the orbital gas flows around Sgr A^{*}, while gravitational collapse and feedback in star-forming regions can locally reorder the field. This magnetic field behavior is similar to that observed in the CMZ of the nuclear starburst galaxy NGC 253. This suggests that despite its current low star formation rate, the CMZ of the Milky Way is analogous to those of more distant, actively star-forming, galaxies.

Keywords

Cite

@article{arxiv.2502.11552,
  title  = {The JCMT BISTRO Survey: Magnetic Fields Align with Orbital Structure in the Galactic Center},
  author = {Janik Karoly and Derek Ward-Thompson and Kate Pattle and Steven N. Longmore and James Di Francesco and Anthony Whitworth and Doug Johnstone and Sarah Sadavoy and Patrick M. Koch and Meng-Zhe Yang and Ray Furuya and Xing Lu and Motohide Tamura and Victor Debattista and David Eden and Jihye Hwang and Frederick Poidevin and Bijas Najimudeen and Szu-Ting Chen and Eun Jung Chung and Simon Coude and Sheng-Jun Lin and Yasuo Doi and Takashi Onaka and Lapo Fanciullo and Tie Liu and Guangxing Li and Pierre Bastien and Tetsuo Hasegawa and Woojin Kwon and Shih-Ping Lai and Keping Qiu},
  journal= {arXiv preprint arXiv:2502.11552},
  year   = {2025}
}

Comments

Accepted in ApJL. 16 pages, 9 figures (4 in main text, 5 in appendices), 5 appendices