Abstract
We present the magnetic field in the dense material of the Central Molecular Zone (CMZ) of the Milky Way, traced in 850 μm polarized dust emission as part of the James Clerk Maxwell Telescope B-fields in STar-forming Region Observations survey. We observe a highly ordered magnetic field across the CMZ between Sgr B2 and Sgr C that is strongly preferentially aligned with the orbital gas flows within the clouds of the CMZ. We find that the observed relative orientations are nonrandom at a >99% confidence level and are consistent with models in which the magnetic field vectors are aligned within 30° 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.
| Original language | English |
|---|---|
| Article number | L22 |
| Journal | Astrophysical Journal Letters |
| Volume | 982 |
| Issue number | 1 |
| Early online date | 20 Mar 2025 |
| DOIs | |
| Publication status | Published - 20 Mar 2025 |
Acknowledgements
We thank the referee for providing thoughtful and constructive feedback that helped improve this manuscript.The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan; Academia Sinica Institute of Astronomy and Astrophysics; the Korea Astronomy and Space Science Institute; the National Astronomical Research Institute of Thailand; Center for Astronomical Mega-Science (as well as the National Key R&D Program of China with No. 2017YFA0402700). Additional funding support is provided by the Science and Technology Facilities Council of the United Kingdom and participating universities and organizations in the United Kingdom, Canada, and Ireland. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. The data taken in this Letter were observed under the project codes M20AL018, M17AP074, and M20AP023. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agency. The Starlink software (M. J. Currie et al. 2014) is currently supported by the East Asian Observatory.
We would also like to thank Jürgen Ott for providing the SWAG NH3 data.
Facilities: JCMT - James Clerk Maxwell Telescope (SCUBA-2, POL-2), ATCA - Australia Telescope Compact Array.
Software: Starlink (M. J. Currie et al. 2014), Astropy (Astropy Collaboration et al. 2013, 2018), SciPy (P. Virtanen et al. 2020), lmfit (M. Newville et al. 2024).
Funding
J.K. is currently supported by the Royal Society under grant No. RF\ERE\231132, as part of project URF\R1\211322 and acknowledges funding from the Moses Holden Scholarship, which supported his PhD. D.W.-T. acknowledge Science and Technology Facilities Council (STFC) support under grant No. ST\R000786\1. K.P. is a Royal Society University Research Fellow, supported by grant No. URF\R1\211322. COOL Research DAO is a Decentralised Autonomous Organisation supporting research in astrophysics aimed at uncovering our cosmic origins. D.J. is supported by NRC Canada and by an NSERC Discovery Grant. X.L. acknowledges support from the National Key R&D Program of China (No. 2022YFA1603101), the Strategic Priority Research Program of the Chinese Academy of Sciences (CAS) grant No. XDB0800300, the National Natural Science Foundation of China (NSFC) through grant Nos. 12273090 and 12322305, the Natural Science Foundation of Shanghai (No. 23ZR1482100), and the CAS "Light of West China" Program No. xbzg-zdsys-202212. F.P. acknowledges support from the MICINN under grant No. PID2022-141915NB-C21. M.T. is supported by JSPS KAKENHI grant No. 24H00242. W.K. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2024-00342488). S.-P.L., M.-Z.Y., and S.-T.C. acknowledges the grants from the National Science and Technology Council of Taiwan under project numbers 109-2112-M-007-010-MY3, 112-2112-M-007-011, and 113-2112-M-007-004. K.Q. acknowledges National Natural Science Foundation of China (NSFC) grant Nos. 12425304 and U1731237, and the National Key R&D Program of China with Nos. 2023YFA1608204 and 2022YFA1603103.
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science