TY - JOUR
T1 - Magnetic fields in massive star-forming regions (MagMaR)
T2 - the magnetic field at the onset of high-mass star formation
AU - Sanhueza, Patricio
AU - Liu, Junhao
AU - Morii, Kaho
AU - Girart, Josep Miquel
AU - Zhang, Qizhou
AU - Stephens, Ian W.
AU - Jackson, James M.
AU - Cortes, Paulo C.
AU - Koch, Patrick M.
AU - Cyganowski, Claudia J.
AU - Saha, Piyali
AU - Beuther, Henrik
AU - Zhang, Suinan
AU - Beltran, Maria T.
AU - Cheng, Yu
AU - Olguin, Fernando A.
AU - Lu, Xing
AU - Choudhury, Spandan
AU - Pattle, Kate
AU - Fernandez-Lopez, Manuel
AU - Hwang, Jihye
AU - Kang, Ji-hyun
AU - Karoly, Janik
AU - Ginsburg, Adam
AU - Lyo, A. -Ran
AU - Taniguchi, Kotomi
AU - Jiao, Wenyu
AU - Eswaraiah, Chakali
AU - Luo, Qiu-yi
AU - Wang, Jia-Wei
AU - Commercon, Benoit
AU - Li, Shanghuo
AU - Xu, Fengwei
AU - Chen, Huei-Ru Vivien
AU - Zapata, Luis A.
AU - Chung, Eun Jung
AU - Nakamura, Fumitaka
AU - Panigrahy, Sandhyarani
AU - Sakai, Takeshi
N1 - Funding: P.S. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI Number JP22H01271 and JP23H01221) of the Japan Society for the Promotion of Science (JSPS). P.C.C. was supported by the NAOJ Research Coordination Committee, NINS (NAOJ-RCC-2202-0401). The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. J.M.G. and P.S. acknowledge support by the grant PID2020-117710GB-I00 (MCI-AEI-FEDER, UE). This work is also partially supported by the program Unidad de Excelencia Maria de Maeztu CEX2020-001058-M. P.S. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI numbers JP22H01271 and JP24K17100) of JSPS. M.T.B. acknowledges financial support through the INAF Large Grant The role of MAGnetic fields in MAssive star formation (MAGMA). Y.C. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI number JP24K17103) of JSPS. 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. C.J.C. acknowledges support from the STFC (grant ST/Y002229/1). K.P. is a Royal Society University Research Fellow, supported by grant No. URF\R1\211322. J.K. is supported by the Royal Society under grant No. RF\ERE\231132, as part of project URF\R1\211322. L.A.Z. acknowledges financial support from CONACyT-280775, UNAM-PAPIIT IN110618, and IN112323 grants, México. C.E. acknowledges the financial support from the grant RJF/2020/000071 as a part of the Ramanujan Fellowship awarded by the Science and Engineering Research Board (SERB). Data analysis was in part carried out on the Multi-wavelength Data Analysis System operated by the Astronomy Data Center (ADC), National Astronomical Observatory of Japan. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2017.1.00101.S, ADS/JAO.ALMA#2018.1.00105.S, ADS/JAO.ALMA# 2016.1.01036.S, and ADS/JAO.ALMA#2017.1.00237.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ.
PY - 2025/2/10
Y1 - 2025/2/10
N2 - A complete understanding of the initial conditions of high-mass star formation and what processes determine multiplicity requires the study of the magnetic field in young massive cores. Using Atacama Large Millimeter/submillimeter Array (ALMA) 250 GHz polarization observations (0."3 = 1000 au) and ALMA 220 GHz high-angular-resolution observations (0."05 = 160 au), we have performed a full energy analysis including the magnetic field at core scales and have assessed what influences the multiplicity inside a massive core previously believed to be in the prestellar phase. With a mass of 31 M⊙, the G11.92 MM2 core has a young CS molecular outflow with a dynamical timescale of a few thousand years. At high resolution, the MM2 core fragments into a binary system, with a projected separation of 505 au and a binary mass ratio of 1.14. Using the Davis–Chandrasekhar–Fermi method with an angle dispersion function analysis, we estimate in this core a magnetic field strength of 6.2 mG and a mass-to-magnetic-flux ratio of 18. The MM2 core is strongly subvirialized, with a virial parameter of 0.064, including the magnetic field. The high mass-to-magnetic-flux ratio and low virial parameter indicate that this massive core is very likely undergoing runaway collapse, which is in direct contradiction with the core accretion model. The MM2 core is embedded in a filament that has a velocity gradient consistent with infall. In line with clump-fed scenarios, the core can grow in mass at a rate of 1.9–5.6 × 10−4 M⊙ yr−1. In spite of the magnetic field having only a minor contribution to the total energy budget at core scales (a few thousands of astronomical units), it likely plays a more important role at smaller scales (a few hundreds of astronomical units) by setting the binary properties. Considering energy ratios and a fragmentation criterion at the core scale, the binary system could have been formed by core fragmentation. The binary system properties (projected separation and mass ratio), however, are also consistent with radiation-magnetohydrodynamic simulations with super-Alfvenic or supersonic (or sonic) turbulence that form binaries by disk fragmentation.
AB - A complete understanding of the initial conditions of high-mass star formation and what processes determine multiplicity requires the study of the magnetic field in young massive cores. Using Atacama Large Millimeter/submillimeter Array (ALMA) 250 GHz polarization observations (0."3 = 1000 au) and ALMA 220 GHz high-angular-resolution observations (0."05 = 160 au), we have performed a full energy analysis including the magnetic field at core scales and have assessed what influences the multiplicity inside a massive core previously believed to be in the prestellar phase. With a mass of 31 M⊙, the G11.92 MM2 core has a young CS molecular outflow with a dynamical timescale of a few thousand years. At high resolution, the MM2 core fragments into a binary system, with a projected separation of 505 au and a binary mass ratio of 1.14. Using the Davis–Chandrasekhar–Fermi method with an angle dispersion function analysis, we estimate in this core a magnetic field strength of 6.2 mG and a mass-to-magnetic-flux ratio of 18. The MM2 core is strongly subvirialized, with a virial parameter of 0.064, including the magnetic field. The high mass-to-magnetic-flux ratio and low virial parameter indicate that this massive core is very likely undergoing runaway collapse, which is in direct contradiction with the core accretion model. The MM2 core is embedded in a filament that has a velocity gradient consistent with infall. In line with clump-fed scenarios, the core can grow in mass at a rate of 1.9–5.6 × 10−4 M⊙ yr−1. In spite of the magnetic field having only a minor contribution to the total energy budget at core scales (a few thousands of astronomical units), it likely plays a more important role at smaller scales (a few hundreds of astronomical units) by setting the binary properties. Considering energy ratios and a fragmentation criterion at the core scale, the binary system could have been formed by core fragmentation. The binary system properties (projected separation and mass ratio), however, are also consistent with radiation-magnetohydrodynamic simulations with super-Alfvenic or supersonic (or sonic) turbulence that form binaries by disk fragmentation.
KW - Dust continuum emission
KW - Polarimetry
KW - Star formation
KW - Star forming regions
KW - Massive stars
KW - Magnetic fields
KW - Young stellar objects
KW - Binary stars
U2 - 10.3847/1538-4357/ad9d40
DO - 10.3847/1538-4357/ad9d40
M3 - Article
SN - 0004-637X
VL - 980
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 1
M1 - 87
ER -