Poster Presentation

ALMA observation of high spatial resolution for magnetic structure in high-mass star-forming region G240.31+0.07

Author(s): Yi-Zhun Chen(NTHU), Huei-Ru Chen (NTHU)

Presenter: Yi-Zhun Chen (National Tsing Hua University)

G240.31+0.07 is a high star formation region at 5.4kpc. The region have at lest one UC HII associated with H2O and OH maser. The bipolar, wide-angle and quasi-parabolic molecular outflow is detected and the hourglass magnetic field aligned within 20◦ of outflow axis. The hot molecular core are derived by the brightness ratio of two H2CO line in the 223 GHz. We present the 223 GHz ALMA dust polarization observation in the massive star-forming region G240.31+0.07. With a beam size of 0.5′′ × 0.3′′, we resolve the dust emission into three cores, with the respective mass estimated to be 14 M⊙ , 10 M⊙ , and 2.7 M ⊙ for MM1, MM2, and MM3 by assuming a dust spectral index of 1.5. Because the data have a high spatial resolution (∼ 0.12 pc) and sensitivity (∼ 0.25 mJy/beam), wezoom up on the magnetic field structure and gravity relation. The magnetic field shows an hourglass-like in northeast-southwest orientation, but the region near MM2 has some rotation trend to east-west.Using the Davis-Chandrasekhar-Fermi (DCF) method, we estimated a magnetic field strength for the plane of sky component.