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27 results on '"Chi-Yan Law"'

1. Exploring Magnetic Fields in Molecular Clouds through Denoising Diffusion Probabilistic Models

Author

Duo Xu, Jenna Karcheski, Chi-Yan Law, Ye Zhu, Chia-Jung Hsu, and Jonathan C. Tan

Subjects
Interstellar medium, Interstellar magnetic fields, Astrostatistics, Astrostatistics techniques, Molecular clouds, Magnetohydrodynamics, Astrophysics, QB460-466
Abstract

Accurately measuring magnetic field strength in the interstellar medium, including giant molecular clouds, remains a significant challenge. We present a machine learning approach using denoising diffusion probabilistic models (DDPMs) to estimate magnetic field strength from synthetic observables such as column density, orientation angles of the dust continuum polarization vector, and line-of-sight (LOS) nonthermal velocity dispersion. We trained three versions of the DDPM model: the 1-channel DDPM (using only column density), the 2-channel DDPM (incorporating both column density and polarization angles), and the 3-channel DDPM (which combines column density, polarization angles, and LOS nonthermal velocity dispersion). The code and trained model are available on GitHub at http://github.com/xuduo117/DDPM_Bmag . We assessed the models on both synthetic test samples and new simulation data that were outside the training set's distribution. The 3-channel DDPM consistently outperformed both the other DDPM variants and the power-law fitting approach based on column density alone, demonstrating its robustness in handling previously unseen data. Additionally, we compared the performance of the Davis–Chandrasekhar–Fermi (DCF) methods, both classical and modified, to the DDPM predictions. The classical DCF method overestimated the magnetic field strength by approximately an order of magnitude. Although the modified DCF method showed improvement over the classical version, it still fell short of the precision achieved by the 3-channel DDPM.

Published
2025
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2. A Tale of Three: Magnetic Fields along the Orion Integral-shaped Filament as Revealed by the JCMT BISTRO Survey

Author

Jintai Wu, Keping Qiu, Frédérick Poidevin, Pierre Bastien, Junhao Liu, Tao-Chung Ching, Tyler L. Bourke, Derek Ward-Thompson, Kate Pattle, Doug Johnstone, Patrick M. Koch, Doris Arzoumanian, Chang Won Lee, Lapo Fanciullo, Takashi Onaka, Jihye Hwang, Valentin J. M. Le Gouellec, Archana Soam, Motohide Tamura, Mehrnoosh Tahani, Chakali Eswaraiah, Hua-Bai Li, David Berry, Ray S. Furuya, Simon Coudé, Woojin Kwon, Sheng-Jun Lin, Jia-Wei Wang, Tetsuo Hasegawa, Shih-Ping Lai, Do-Young Byun, Zhiwei Chen, Huei-Ru Vivien Chen, Wen Ping Chen, Mike Chen, Jungyeon Cho, Youngwoo Choi, Yunhee Choi, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Sophia Dai, James Di Francesco, Pham Ngoc Diep, Yasuo Doi, Hao-Yuan Duan, Yan Duan, David Eden, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Saeko Hayashi, Thiem Hoang, Martin Houde, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Vera Könyves, Ji-hyun Kang, Miju Kang, Janik Karoly, Akimasa Kataoka, Koji Kawabata, Shinyoung Kim, Mi-Ryang Kim, Kyoung Hee Kim, Kee-Tae Kim, Jongsoo Kim, Hyosung Kim, Gwanjeong Kim, Florian Kirchschlager, Jason Kirk, Masato I.N. Kobayashi, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Hyeseung Lee, Chin-Fei Lee, Sang-Sung Lee, Jeong-Eun Lee, Dalei Li, Di Li, Guangxing Li, Sheng-Yuan Liu, Tie Liu, Hong-Li Liu, Xing Lu, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Mark Rawlings, Brendan Retter, John Richer, Andrew Rigby, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Masumichi Seta, Ekta Sharma, Yoshito Shimajiri, Hiroko Shinnaga, Ya-Wen Tang, Xindi Tang, Hoang Duc Thuong, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Anthony Whitworth, Jinjin Xie, Meng-Zhe Yang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Guoyin Zhang, Chuan-Peng Zhang, Yapeng Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, Stewart Eyres, Sam Falle, Jean-François Robitaille, and Sven van Loo

Subjects
Star formation, Interstellar magnetic fields, Interstellar clouds, Polarimetry, Astrophysics, QB460-466
Abstract

As part of the B -fields In Star-forming Region Observations survey, we present James Clerk Maxwell Telescope (JCMT) 850 μ m polarimetric observations toward the Orion integral-shaped filament (ISF) that covers three portions known as OMC-1, OMC-2, and OMC-3. The magnetic field threading the ISF seen in the JCMT POL-2 map appears as a tale of three: pinched for OMC-1, twisted for OMC-2, and nearly uniform for OMC-3. A multiscale analysis shows that the magnetic field structure in OMC-3 is very consistent at all the scales, whereas the field structure in OMC-2 shows no correlation across different scales. In OMC-1, the field retains its mean orientation from large to small scales but shows some deviations at small scales. Histograms of relative orientations between the magnetic field and filaments reveal a bimodal distribution for OMC-1, a relatively random distribution for OMC-2, and a distribution with a predominant peak at 90 ^∘ for OMC-3. Furthermore, the magnetic fields in OMC-1 and OMC-3 both appear to be aligned perpendicular to the fibers, which are denser structures within the filament, but the field in OMC-2 is aligned along with the fibers. All these suggest that gravity, turbulence, and magnetic field are each playing a leading role in OMC-1, 2, and 3, respectively. While OMC-2 and 3 have almost the same gas mass, density, and nonthermal velocity dispersion, there are on average younger and fewer young stellar objects in OMC-3, providing evidence that a stronger magnetic field will induce slower and less efficient star formation in molecular clouds.

Published
2024
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3. Magnetic Fields in Massive Star-forming Regions (MagMaR): Unveiling an Hourglass Magnetic Field in G333.46–0.16 Using ALMA

Author

Piyali Saha, Patricio Sanhueza, Marco Padovani, Josep M. Girart, Paulo C. Cortés, Kaho Morii, Junhao Liu, Á. Sánchez-Monge, Daniele Galli, Shantanu Basu, Patrick M. Koch, Maria T. Beltrán, Shanghuo Li, Henrik Beuther, Ian W. Stephens, Fumitaka Nakamura, Qizhou Zhang, Wenyu Jiao, M. Fernández-López, Jihye Hwang, Eun Jung Chung, Kate Pattle, Luis A. Zapata, Fengwei Xu, Fernando A. Olguin, Ji-hyun Kang, Janik Karoly, Chi-Yan Law, Jia-Wei Wang, Timea Csengeri, Xing Lu, Yu Cheng, Jongsoo Kim, Spandan Choudhury, Huei-Ru Vivien Chen, and Charles L. H. Hull

Subjects
Dust continuum emission, Magnetic fields, Polarimetry, Star formation, Astrophysics, QB460-466
Abstract

The contribution of the magnetic field to the formation of high-mass stars is poorly understood. We report the high angular resolution (∼0.″3, 870 au) map of the magnetic field projected on the plane of the sky ( B _POS ) toward the high-mass star-forming region G333.46−0.16 (G333), obtained with the Atacama Large Millimeter/submillimeter Array at 1.2 mm as part of the Magnetic fields in Massive star-forming Regions survey. The B _POS morphology found in this region is consistent with a canonical “hourglass” with an embedded flattened envelope in a perpendicular direction, which suggests a dynamically important field. This region is fragmented into two protostars that appear to be gravitationally bound in a stable binary system with a separation of ∼1740 au. Interestingly, by analyzing H ^13 CO ^+ ( J = 3–2) line emission, we find no velocity gradient over the extent of the continuum, which is consistent with a strong field. We model the B _POS , obtaining a marginally supercritical mass-to-flux ratio of 1.43, suggesting an initially strongly magnetized environment. Based on the Davis–Chandrasekhar–Fermi method, the magnetic field strength toward G333 is estimated to be 5.7 mG. The absence of strong rotation and outflows toward the central region of G333 suggests strong magnetic braking, consistent with a highly magnetized environment. Our study shows that despite being a strong regulator, the magnetic energy fails to prevent the process of fragmentation, as revealed by the formation of the two protostars in the central region.

Published
2024
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4. The JCMT BISTRO Survey: The Magnetic Fields of the IC 348 Star-forming Region

Author

Youngwoo Choi, Woojin Kwon, Kate Pattle, Doris Arzoumanian, Tyler L. Bourke, Thiem Hoang, Jihye Hwang, Patrick M. Koch, Sarah Sadavoy, Pierre Bastien, Ray Furuya, Shih-Ping Lai, Keping Qiu, Derek Ward-Thompson, David Berry, Do-Young Byun, Huei-Ru Vivien Chen, Wen Ping Chen, Mike Chen, Zhiwei Chen, Tao-Chung Ching, Jungyeon Cho, Minho Choi, Yunhee Choi, Simon Coudé, Antonio Chrysostomou, Eun Jung Chung, Sophia Dai, Victor Debattista, James Di Francesco, Pham Ngoc Diep, Yasuo Doi, Hao-Yuan Duan, Yan Duan, Chakali Eswaraiah, Lapo Fanciullo, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Tetsuo Hasegawa, Martin Houde, Charles L. H. Hull, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Doug Johnstone, Janik Karoly, Vera Könyves, Ji-hyun Kang, Miju Kang, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Jongsoo Kim, Shinyoung Kim, Gwanjeong Kim, Kyoung Hee Kim, Mi-Ryang Kim, Kee-Tae Kim, Hyosung Kim, Florian Kirchschlager, Jason Kirk, Masato I. N. Kobayashi, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Chang Won Lee, Hyeseung Lee, Chin-Fei Lee, Jeong-Eun Lee, Sang-Sung Lee, Dalei Li, Di Li, Guangxing Li, Hua-bai Li, Sheng-Jun Lin, Hong-Li Liu, Tie Liu, Sheng-Yuan Liu, Junhao Liu, Steven Longmore, Xing Lu, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Takashi Onaka, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Mark Rawlings, Brendan Retter, John Richer, Andrew Rigby, Hiro Saito, Giorgio Savini, Masumichi Seta, Ekta Sharma, Yoshito Shimajiri, Hiroko Shinnaga, Archana Soam, Mehrnoosh Tahani, Motohide Tamura, Ya-Wen Tang, Xindi Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Jia-Wei Wang, Anthony Whitworth, Jintai Wu, Jinjin Xie, Meng-Zhe Yang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Guoyin Zhang, Yapeng Zhang, Chuan-Peng Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, David Eden, Stewart Eyres, Sam Falle, Valentin J. M. Le Gouellec, Frédérick Poidevin, and Sven van Loo

Subjects
Interstellar medium, Interstellar magnetic fields, Interstellar filaments, Molecular clouds, Star formation, Polarimetry, Astrophysics, QB460-466
Abstract

We present 850 μ m polarization observations of the IC 348 star-forming region in the Perseus molecular cloud as part of the B-fields In STar-forming Region Observation survey. We study the magnetic properties of two cores (HH 211 MMS and IC 348 MMS) and a filamentary structure of IC 348. We find that the overall field tends to be more perpendicular than parallel to the filamentary structure of the region. The polarization fraction decreases with intensity, and we estimate the trend by power law and the mean of the Rice distribution fittings. The power indices for the cores are much smaller than 1, indicative of possible grain growth to micron size in the cores. We also measure the magnetic field strengths of the two cores and the filamentary area separately by applying the Davis–Chandrasekhar–Fermi method and its alternative version for compressed medium. The estimated mass-to-flux ratios are 0.45–2.20 and 0.63–2.76 for HH 211 MMS and IC 348 MMS, respectively, while the ratios for the filament are 0.33–1.50. This result may suggest that the transition from subcritical to supercritical conditions occurs at the core scale (∼0.05 pc) in the region. In addition, we study the energy balance of the cores and find that the relative strength of turbulence to the magnetic field tends to be stronger for IC 348 MMS than for HH 211 MMS. The result could potentially explain the different configurations inside the two cores: a single protostellar system in HH 211 MMS and multiple protostars in IC 348 MMS.

Published
2024
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5. Astrochemical Diagnostics of the Isolated Massive Protostar G28.20-0.05

Author

Prasanta Gorai, Chi-Yan Law, Jonathan C. Tan, Yichen Zhang, Rubén Fedriani, Kei E. I. Tanaka, Mélisse Bonfand, Giuliana Cosentino, Diego Mardones, Maria T. Beltrán, and Guido Garay

Subjects
Star formation, Astrochemistry, Complex organic molecules, Spectral line identification, Massive stars, Interstellar medium, Astrophysics, QB460-466
Abstract

We study the astrochemical diagnostics of the isolated massive protostar G28.20-0.05. We analyze data from Atacama Large Millimeter/submillimeter Array 1.3 mm observations with a resolution of 0.″2 (∼1000 au). We detect emission from a wealth of species, including oxygen-bearing (e.g., H _2 CO, CH _3 OH, CH _3 OCH _3 ), sulfur-bearing (SO _2 , H _2 S), and nitrogen-bearing (e.g., HNCO, NH _2 CHO, C _2 H _3 CN, C _2 H _5 CN) molecules. We discuss their spatial distributions, physical conditions, correlation between different species, and possible chemical origins. In the central region near the protostar, we identify three hot molecular cores (HMCs). HMC1 is part of a millimeter continuum ring-like structure, is closest in projection to the protostar, has the highest temperature of ∼300 K, and shows the most line-rich spectra. HMC2 is on the other side of the ring, has a temperature of ∼250 K, and is of intermediate chemical complexity. HMC3 is further away, ∼3000 au in projection, cooler (∼70 K), and is the least line-rich. The three HMCs have similar mass surface densities (∼10 g cm ^−2 ), number densities ( n _H ∼ 10 ^9 cm ^−3 ), and masses of a few solar masses. The total gas mass in the cores and in the region out to 3000 au is ∼25 M _⊙ , which is comparable to that of the central protostar. Based on spatial distributions of peak line intensities as a function of excitation energy, we infer that the HMCs are externally heated by the protostar. We estimate column densities and abundances of the detected species and discuss the implications for hot core astrochemistry.

Published
2024
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6. Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-mass Star-forming Region NGC 2264: Global Properties and Local Magnetogravitational Configurations

Author

Jia-Wei Wang, Patrick M. Koch, Seamus D. Clarke, Gary Fuller, Nicolas Peretto, Ya-Wen Tang, Hsi-Wei Yen, Shih-Ping Lai, Nagayoshi Ohashi, Doris Arzoumanian, Doug Johnstone, Ray Furuya, Shu-ichiro Inutsuka, Chang Won Lee, Derek Ward-Thompson, Valentin J. M. Le Gouellec, Hong-Li Liu, Lapo Fanciullo, Jihye Hwang, Kate Pattle, Frédérick Poidevin, Mehrnoosh Tahani, Takashi Onaka, Mark G. Rawlings, Eun Jung Chung, Junhao Liu, A-Ran Lyo, Felix Priestley, Thiem Hoang, Motohide Tamura, David Berry, Pierre Bastien, Tao-Chung Ching, Simon Coudé, Woojin Kwon, Mike Chen, Chakali Eswaraiah, Archana Soam, Tetsuo Hasegawa, Keping Qiu, Tyler L. Bourke, Do-Young Byun, Zhiwei Chen, Huei-Ru Vivien Chen, Wen Ping Chen, Jungyeon Cho, Minho Choi, Yunhee Choi, Youngwoo Choi, Antonio Chrysostomou, Sophia Dai, James Di Francesco, Pham Ngoc Diep​, Yasuo Doi, Yan Duan, Hao-Yuan Duan, David Eden, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Saeko Hayashi, Martin Houde, Tsuyoshi Inoue, Kazunari Iwasaki, Il-Gyo Jeong, Vera Könyves, Ji-hyun Kang, Miju Kang, Janik Karoly, Akimasa Kataoka, Koji Kawabata, Zacariyya Khan, Mi-Ryang Kim, Kee-Tae Kim, Kyoung Hee Kim, Shinyoung Kim, Jongsoo Kim, Hyosung Kim, Gwanjeong Kim, Florian Kirchschlager, Jason Kirk, Masato I. N. Kobayashi, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Sang-Sung Lee, Hyeseung Lee, Jeong-Eun Lee, Chin-Fei Lee, Dalei Li, Hua-bai Li, Guangxing Li, Di Li, Sheng-Jun Lin, Tie Liu, Sheng-Yuan Liu, Xing Lu, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Geumsook Park, Harriet Parsons, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Brendan Retter, John Richer, Andrew Rigby, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Masumichi Seta, Ekta Sharma, Yoshito Shimajiri, Hiroko Shinnaga, Xindi Tang, Hoang Duc Thuong, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Anthony Whitworth, Jintai Wu, Jinjin Xie, Meng-Zhe Yang, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Chuan-Peng Zhang, Yapeng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, Stewart Eyres, Sam Falle, Jean-François Robitaille, and Sven van Loo

Subjects
Collapsing clouds, Interstellar filaments, Molecular clouds, Interstellar magnetic fields, Interstellar medium, Polarimetry, Astrophysics, QB460-466
Abstract

We report 850 μ m continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B -fields In STar forming Regions Observations large program on the James Clerk Maxwell Telescope. These data reveal a well-structured nonuniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30° from north to east. Field strength estimates and a virial analysis of the major clumps indicate that NGC 2264C is globally dominated by gravity, while in 2264D, magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and longitudinal collapsing, driven by the region's global gravity.

Published
2024
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7. Polarized Light from Massive Protoclusters (POLIMAP). I. Dissecting the Role of Magnetic Fields in the Massive Infrared Dark Cloud G28.37+0.07

Author

Chi-Yan Law, Jonathan C. Tan, Raphael Skalidis, Larry Morgan, Duo Xu, Felipe de Oliveira Alves, Ashley T. Barnes, Natalie Butterfield, Paola Caselli, Giuliana Cosentino, Francesco Fontani, Jonathan D. Henshaw, Izaskun Jimenez-Serra, and Wanggi Lim

Subjects
Star forming regions, Magnetic fields, Infrared dark clouds, Polarimetry, Astrophysics, QB460-466
Abstract

Magnetic fields may play a crucial role in setting the initial conditions of massive star and star cluster formation. To investigate this, we report SOFIA-HAWC+ 214 μ m observations of polarized thermal dust emission and high-resolution GBT-Argus C ^18 O(1-0) observations toward the massive Infrared Dark Cloud (IRDC) G28.37+0.07. Considering the local dispersion of B -field orientations, we produce a map of the B -field strength of the IRDC, which exhibits values between ∼0.03 and 1 mG based on a refined Davis–Chandrasekhar–Fermi method proposed by Skalidis & Tassis. Comparing to a map of inferred density, the IRDC exhibits a B – n relation with a power-law index of 0.51 ± 0.02, which is consistent with a scenario of magnetically regulated anisotropic collapse. Consideration of the mass-to-flux ratio map indicates that magnetic fields are dynamically important in most regions of the IRDC. A virial analysis of a sample of massive, dense cores in the IRDC, including evaluation of magnetic and kinetic internal and surface terms, indicates consistency with virial equilibrium, sub-Alfvénic conditions, and a dominant role for B -fields in regulating collapse. A clear alignment of magnetic field morphology with the direction of the steepest column density gradient is also detected. However, there is no preferred orientation of protostellar outflow directions with the B -field. Overall, these results indicate that magnetic fields play a crucial role in regulating massive star and star cluster formation, and therefore they need to be accounted for in theoretical models of these processes.

Published
2024
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8. Application of Convolutional Neural Networks to Predict Magnetic Fields’ Directions in Turbulent Clouds

Author

Duo Xu, Chi-Yan Law, and Jonathan C. Tan

Subjects
Interstellar medium, Interstellar magnetic fields, Convolutional neural networks, Molecular clouds, Magnetohydrodynamics, Astrophysics, QB460-466
Abstract

We adopt the deep learning method casi-3d (convolutional approach to structure identification-3D) to infer the orientation of magnetic fields in sub-/trans-Alfvénic turbulent clouds from molecular line emission. We carry out magnetohydrodynamic simulations with different magnetic field strengths and use these to generate synthetic observations. We apply the 3D radiation transfer code radmc-3d to model ^12 CO and ^13 CO (J = 1−0) line emission from the simulated clouds and then train a casi-3d model on these line emission data cubes to predict magnetic field morphology at the pixel level. The trained casi-3d model is able to infer magnetic field directions with a low error (≲10° for sub-Alfvénic samples and ≲30° for trans-Alfvénic samples). We further test the performance of casi-3d on a real sub-/trans- Alfvénic region in Taurus. The casi-3d prediction is consistent with the magnetic field direction inferred from Planck dust polarization measurements. We use our developed methods to produce a new magnetic field map of Taurus that has a three times higher angular resolution than the Planck map.

Published
2023
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9. First BISTRO Observations of the Dark Cloud Taurus L1495A-B10: The Role of the Magnetic Field in the Earliest Stages of Low-mass Star Formation

Author

Derek Ward-Thompson, Janik Karoly, Kate Pattle, Anthony Whitworth, Jason Kirk, David Berry, Pierre Bastien, Tao-Chung Ching, Simon Coudé, Jihye Hwang, Woojin Kwon, Archana Soam, Jia-Wei Wang, Tetsuo Hasegawa, Shih-Ping Lai, Keping Qiu, Doris Arzoumanian, Tyler L. Bourke, Do-Young Byun, Huei-Ru Vivien Chen, Wen Ping Chen, Mike Chen, Zhiwei Chen, Jungyeon Cho, Minho Choi, Youngwoo Choi, Yunhee Choi, Antonio Chrysostomou, Eun Jung Chung, Sophia Dai, Victor Debattista, James Di Francesco, Pham Ngoc Diep, Yasuo Doi, Hao-Yuan Duan, Yan Duan, Chakali Eswaraiah, Lapo Fanciullo, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Ray Furuya, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Saeko Hayashi, Thiem Hoang, Martin Houde, Charles L. H. Hull, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Doug Johnstone, Vera Könyves, Ji-hyun Kang, Miju Kang, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Jongsoo Kim, Shinyoung Kim, Gwanjeong Kim, Kyoung Hee Kim, Mi-Ryang Kim, Kee-Tae Kim, Hyosung Kim, Florian Kirchschlager, Masato I. N. Kobayashi, Patrick M. Koch, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Chang Won Lee, Hyeseung Lee, Yong-Hee Lee, Chin-Fei Lee, Jeong-Eun Lee, Sang-Sung Lee, Dalei Li, Di Li, Guangxing Li, Hua-bai Li, Sheng-Jun Lin, Hong-Li Liu, Tie Liu, Sheng-Yuan Liu, Junhao Liu, Steven Longmore, Xing Lu, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Takashi Onaka, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Mark Rawlings, Brendan Retter, John Richer, Andrew Rigby, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Mehrnoosh Tahani, Motohide Tamura, Ya-Wen Tang, Xindi Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Jintai Wu, Jinjin Xie, Meng-Zhe Yang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Guoyin Zhang, Yapeng Zhang, Chuan-Peng Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, David Eden, Stewart Eyres, Sam Falle, Valentin J. M. Le Gouellec, Frédérick Poidevin, Jean-François Robitaille, and Sven van Loo

Subjects
Interstellar magnetic fields, Molecular clouds, Starlight polarization, Collapsing clouds, Interstellar filaments, Astrophysics, QB460-466
Abstract

We present BISTRO Survey 850 μ m dust emission polarization observations of the L1495A-B10 region of the Taurus molecular cloud, taken at the James Clerk Maxwell Telescope (JCMT). We observe a roughly triangular network of dense filaments. We detect nine of the dense starless cores embedded within these filaments in polarization, finding that the plane-of-sky orientation of the core-scale magnetic field lies roughly perpendicular to the filaments in almost all cases. We also find that the large-scale magnetic field orientation measured by Planck is not correlated with any of the core or filament structures, except in the case of the lowest-density core. We propose a scenario for early prestellar evolution that is both an extension to, and consistent with, previous models, introducing an additional evolutionary transitional stage between field-dominated and matter-dominated evolution, observed here for the first time. In this scenario, the cloud collapses first to a sheet-like structure. Uniquely, we appear to be seeing this sheet almost face on. The sheet fragments into filaments, which in turn form cores. However, the material must reach a certain critical density before the evolution changes from being field dominated to being matter dominated. We measure the sheet surface density and the magnetic field strength at that transition for the first time and show consistency with an analytical prediction that had previously gone untested for over 50 yr.

Published
2023
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10. The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43

Author

Janik Karoly, Derek Ward-Thompson, Kate Pattle, David Berry, Anthony Whitworth, Jason Kirk, Pierre Bastien, Tao-Chung Ching, Simon Coudé, Jihye Hwang, Woojin Kwon, Archana Soam, Jia-Wei Wang, Tetsuo Hasegawa, Shih-Ping Lai, Keping Qiu, Doris Arzoumanian, Tyler L. Bourke, Do-Young Byun, Huei-Ru Vivien Chen, Wen Ping Chen, Mike Chen, Zhiwei Chen, Jungyeon Cho, Minho Choi, Youngwoo Choi, Yunhee Choi, Antonio Chrysostomou, Eun Jung Chung, Sophia Dai, Victor Debattista, James Di Francesco, Pham Ngoc Diep, Yasuo Doi, Hao-Yuan Duan, Yan Duan, Chakali Eswaraiah, Lapo Fanciullo, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Ray Furuya, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Thiem Hoang, Martin Houde, Charles L. H. Hull, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Doug Johnstone, Vera Könyves, Ji-hyun Kang, Miju Kang, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Jongsoo Kim, Shinyoung Kim, Gwanjeong Kim, Kyoung Hee Kim, Mi-Ryang Kim, Kee-Tae Kim, Hyosung Kim, Florian Kirchschlager, Masato I. N. Kobayashi, Patrick M. Koch, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Chang Won Lee, Hyeseung Lee, Yong-Hee Lee, Chin-Fei Lee, Jeong-Eun Lee, Sang-Sung Lee, Dalei Li, Di Li, Guangxing Li, Hua-bai Li, Sheng-Jun Lin, Hong-Li Liu, Tie Liu, Sheng-Yuan Liu, Junhao Liu, Steven Longmore, Xing Lu, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Takashi Onaka, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Mark Rawlings, Brendan Retter, John Richer, Andrew Rigby, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Masumichi Seta, Ekta Sharma, Yoshito Shimajiri, Hiroko Shinnaga, Mehrnoosh Tahani, Motohide Tamura, Ya-Wen Tang, Xindi Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Jintai Wu, Jinjin Xie, Meng-Zhe Yang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Guoyin Zhang, Yapeng Zhang, Chuan-Peng Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, David Eden, Stewart Eyres, Sam Falle, Valentin J. M. Le Gouellec, Frédérick Poidevin, Jean-François Robitaille, and Sven van Loo

Subjects
Stellar-interstellar interactions, Interstellar magnetic fields, Young stellar objects, Dust continuum emission, Starlight polarization, Molecular clouds, Astrophysics, QB460-466
Abstract

We present observations of polarized dust emission at 850 μ m from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense ( ${N}_{{{\rm{H}}}_{2}}\sim {10}^{22}$ –10 ^23 cm ^−2 ) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to ∼160 ± 30 μ G in the main starless core and up to ∼90 ± 40 μ G in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvénic. We also present a new method of data reduction for these denser but fainter objects like starless cores.

Published
2023
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11. JCMT BISTRO Observations: Magnetic Field Morphology of Bubbles Associated with NGC 6334

Author

Mehrnoosh Tahani, Pierre Bastien, Ray S. Furuya, Kate Pattle, Doug Johnstone, Doris Arzoumanian, Yasuo Doi, Tetsuo Hasegawa, Shu-ichiro Inutsuka, Simon Coudé, Laura Fissel, Michael Chun-Yuan Chen, Frédérick Poidevin, Sarah Sadavoy, Rachel Friesen, Patrick M. Koch, James Di Francesco, Gerald H. Moriarty-Schieven, Zhiwei Chen, Eun Jung Chung, Chakali Eswaraiah, Lapo Fanciullo, Tim Gledhill, Valentin J. M. Le Gouellec, Thiem Hoang, Jihye Hwang, Ji-hyun Kang, Kyoung Hee Kim, Florian Kirchschlager, Woojin Kwon, Chang Won Lee, Hong-Li Liu, Takashi Onaka, Mark G. Rawlings, Archana Soam, Motohide Tamura, Xindi Tang, Kohji Tomisaka, Anthony P. Whitworth, Jungmi Kwon, Thuong D. Hoang, Matt Redman, David Berry, Tao-Chung Ching, Jia-Wei Wang, Shih-Ping Lai, Keping Qiu, Derek Ward-Thompson, Martin Houde, Do-Young Byun, Huei-Ru Vivien Chen, Wen Ping Chen, Jungyeon Cho, Minho Choi, Yunhee Choi, Antonio Chrysostomou, Pham Ngoc Diep, Hao-Yuan Duan, Jason Fiege, Erica Franzmann, Per Friberg, Gary Fuller, Sarah F. Graves, Jane S. Greaves, Matt J. Griffin, Qilao Gu, Ilseung Han, Jennifer Hatchell, Saeko S. Hayashi, Charles L. H. Hull, Tsuyoshi Inoue, Kazunari Iwasaki, Il-Gyo Jeong, Yoshihiro Kanamori, Miju Kang, Sung-ju Kang, Akimasa Kataoka, Koji S. Kawabata, Francisca Kemper, Gwanjeong Kim, Jongsoo Kim, Kee-Tae Kim, Mi-Ryang Kim, Shinyoung Kim, Jason M. Kirk, Masato I. N. Kobayashi, Vera Konyves, Takayoshi Kusune, Kevin Lacaille, Chi-Yan Law, Chin-Fei Lee, Hyeseung Lee, Jeong-Eun Lee, Sang-Sung Lee, Yong-Hee Lee, Dalei Li, Di Li, Hua-bai Li, Junhao Liu, Sheng-Yuan Liu, Tie Liu, Ilse de Looze, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Brenda C. Matthews, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Geumsook Park, Harriet Parsons, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Brendan Retter, John Richer, Andrew Rigby, Hiro Saito, Giorgio Savini, Anna M. M. Scaife, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Ya-Wen Tang, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Chuan-Peng Zhang, Guoyin Zhang, Yapeng Zhang, Jianjun Zhou, Lei Zhu, Philippe André, C. Darren Dowell, Stewart P. S. Eyres, Sam Falle, Sven van Loo, and Jean-François Robitaille

Subjects
H II regions, Interstellar magnetic fields, Star formation, Molecular clouds, Dust continuum emission, Astrophysics, QB460-466
Abstract

We study the H ii regions associated with the NGC 6334 molecular cloud observed in the submillimeter and taken as part of the B -fields In STar-forming Region Observations Survey. In particular, we investigate the polarization patterns and magnetic field morphologies associated with these H ii regions. Through polarization pattern and pressure calculation analyses, several of these bubbles indicate that the gas and magnetic field lines have been pushed away from the bubble, toward an almost tangential (to the bubble) magnetic field morphology. In the densest part of NGC 6334, where the magnetic field morphology is similar to an hourglass, the polarization observations do not exhibit observable impact from H ii regions. We detect two nested radial polarization patterns in a bubble to the south of NGC 6334 that correspond to the previously observed bipolar structure in this bubble. Finally, using the results of this study, we present steps (incorporating computer vision; circular Hough transform) that can be used in future studies to identify bubbles that have physically impacted magnetic field lines.

Published
2023
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12. The SOFIA Massive (SOMA) Star Formation Survey. IV. Isolated Protostars

Author

Rubén Fedriani, Jonathan C. Tan, Zoie Telkamp, Yichen Zhang, Yao-Lun Yang, Mengyao Liu, James M. De Buizer, Chi-Yan Law, Maria T. Beltran, Viviana Rosero, Kei E. I. Tanaka, Giuliana Cosentino, Prasanta Gorai, Juan Farias, Jan E. Staff, and Barbara Whitney

Subjects
Massive stars, Star formation, Interstellar medium, Jets, Infrared sources, Protostars, Astrophysics, QB460-466
Abstract

We present ∼10–40 μ m SOFIA-FORCAST images of 11 isolated protostars as part of the SOFIA Massive (SOMA) Star Formation Survey, with this morphological classification based on 37 μ m imaging. We develop an automated method to define source aperture size using the gradient of its background-subtracted enclosed flux and apply this to build spectral energy distributions (SEDs). We fit the SEDs with radiative transfer models, developed within the framework of turbulent core accretion (TCA) theory, to estimate key protostellar properties. Here, we release the sedcreator python package that carries out these methods. The SEDs are generally well fitted by the TCA models, from which we infer initial core masses M _c ranging from 20–430 M _⊙ , clump mass surface densities Σ _cl ∼ 0.3–1.7 g cm ^−2 , and current protostellar masses m _* ∼ 3–50 M _⊙ . From a uniform analysis of the 40 sources in the full SOMA survey to date, we find that massive protostars form across a wide range of clump mass surface density environments, placing constraints on theories that predict a minimum threshold Σ _cl for massive star formation. However, the upper end of the m _* −Σ _cl distribution follows trends predicted by models of internal protostellar feedback that find greater star formation efficiency in higher Σ _cl conditions. We also investigate protostellar far-IR variability by comparison with IRAS data, finding no significant variation over an ∼40 yr baseline.

Published
2022
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13. ALMA–IRDC: dense gas mass distribution from cloud to core scales

Author

Jonathan C. Tan, I. Jimenez-Serra, Richard J. Parker, Ashley T. Barnes, Álvaro Sánchez-Monge, Adam Avison, L. Moser, Francesco Fontani, K. Wang, Frank Bigiel, Steven N. Longmore, Jonathan D. Henshaw, Jaime E. Pineda, Chi Yan Law, Giuliana Cosentino, Paola Caselli, Shuo Kong, Siyi Feng, Avison, A. [0000-0002-2562-8609], European Research Council (ERC), Agencia Estatal de Investigación (AEI), Deutsche Forschungsgemeinschaft (DFG), East Asia Core Observatories Association (EACOA), National Natural Science Foundation of China (NSFC), National Key Research and Development Program of China, and Peking University

Subjects
Milky Way, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, 01 natural sciences, Virial theorem, Spectral line, massive [stars], 0103 physical sciences, Cluster (physics), 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, formation [stars], Mass distribution, 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Orders of magnitude (time), 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), clouds [ISM]
Abstract

Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high-mass star formation (HMSF). Here we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as some of the best candidates to study HMSF within the Milky Way. To do so, we have obtained a set of large mosaics covering these IRDCs with ALMA at band 3 (or 3mm). These observations have a high angular resolution (~3arcsec or ~0.05pc), and high continuum and spectral line sensitivity (~0.15mJy/beam and ~0.2K per 0.1km/s channel at the N2H+(1-0) transition). From the dust continuum emission, we identify 96 cores ranging from low- to high-mass (M = 3.4 to 50.9Msun) that are gravitationally bound (alpha_vir = 0.3 to 1.3) and which would require magnetic field strengths of B = 0.3 to 1.0mG to be in virial equilibrium. We combine these results with a homogenised catalogue of literature cores to recover the hierarchical structure within these clouds over four orders of magnitude in spatial scale (0.01pc to 10pc). Using supplementary observations at an even higher angular resolution, we find that the smallest fragments (16Msun without further fragmentation. These high-mass cores contain trans-sonic non-thermal motions, are kinematically sub-virial, and require moderate magnetic field strengths for support against collapse. The identification of these potential sites of high-mass star formation represents a key step in allowing us to test the predictions from high-mass star and cluster formation theories., 21(+6 in appendix) pages, 12(+3) figures, 3(+3) tables. Machine-readable versions of Table A1, A2 and A3 are available online. Accepted for publication in MNRAS

Published
2021
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14. The links between magnetic fields and filamentary clouds – III. Field-regulated mass cumulative functions

Author

Zhuo Cao, Chi-Yung Ng, Chi Yan Law, and Hua-bai Li

Subjects
Physics, Field (physics), Mass distribution, Star formation, Molecular cloud, Isotropy, Fragmentation (computing), Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Magnetic field, 010104 statistics & probability, Space and Planetary Science, Orientation (geometry), 0103 physical sciences, 0101 mathematics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

During the past decade, the dynamical importance of magnetic fields in molecular clouds has been increasingly recognized, as observational evidence has accumulated. However, how a magnetic field affects star formation is still unclear. Typical star formation models still treat a magnetic fields as an isotropic pressure, ignoring the fundamental property of dynamically important magnetic fields: their direction. This study builds on our previous work, which demonstrated how the mean magnetic field orientation relative to the global cloud elongation can affect cloud fragmentation. After the linear mass distribution reported earlier, we show here that the mass cumulative function (MCF) of a cloud is also regulated by the field orientation. A cloud elongated closer to the field direction tends to have a shallower MCF: in other words, a higher portion of the gas is at high density. The evidence is consistent with our understanding of the bimodal star formation efficiency discovered earlier, which is also correlated with the field orientation.

Published
2020
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15. B-fields in Star-forming Region Observations (BISTRO): Magnetic Fields in the Filamentary Structures of Serpens Main

Author

Woojin Kwon, Kate Pattle, Sarah Sadavoy, Charles L. H. Hull, Doug Johnstone, Derek Ward-Thompson, James Di Francesco, Patrick M. Koch, Ray Furuya, Yasuo Doi, Valentin J. M. Le Gouellec, Jihye Hwang, A-Ran Lyo, Archana Soam, Xindi Tang, Thiem Hoang, Florian Kirchschlager, Chakali Eswaraiah, Lapo Fanciullo, Kyoung Hee Kim, Takashi Onaka, Vera Könyves, Ji-hyun Kang, Chang Won Lee, Motohide Tamura, Pierre Bastien, Tetsuo Hasegawa, Shih-Ping Lai, Keping Qiu, David Berry, Doris Arzoumanian, Tyler L. Bourke, Do-Young Byun, Wen Ping Chen, Huei-Ru Vivien Chen, Mike Chen, Zhiwei Chen, Tao-Chung Ching, Jungyeon Cho, Yunhee Choi, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Simon Coudé, Sophia Dai, Pham Ngoc Diep, Yan Duan, Hao-Yuan Duan, David Eden, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Jennifer Hatchell, Saeko Hayashi, Martin Houde, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Miju Kang, Janik Karoly, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Kee-Tae Kim, Gwanjeong Kim, Mi-Ryang Kim, Shinyoung Kim, Jongsoo Kim, Jason Kirk, Masato I. N. Kobayashi, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Chin-Fei Lee, Yong-Hee Lee, Hyeseung Lee, Jeong-Eun Lee, Sang-Sung Lee, Dalei Li, Di Li, Hua-bai Li, Sheng-Jun Lin, Sheng-Yuan Liu, Hong-Li Liu, Junhao Liu, Tie Liu, Xing Lu, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Jonathan Rawlings, Mark G. Rawlings, Brendan Retter, John Richer, Andrew Rigby, Hiro Saito, Giorgio Savini, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Mehrnoosh Tahani, Ya-Wen Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Jia-Wei Wang, Anthony Whitworth, Jintai Wu, Jinjin Xie, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Yapeng Zhang, Chuan-Peng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, Stewart Eyres, Sam Falle, Jean-François Robitaille, Sven van Loo, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France

Subjects
POLARIZATION, FOS: Physical sciences, F500, IMAGING POLARIMETRY, 1ST, INTERSTELLAR CLOUDS, Astrophysics::Solar and Stellar Astrophysics, SCUBA-2, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], LEGACY, Astronomy and Astrophysics, VELOCITY, Astrophysics - Astrophysics of Galaxies, SPITZER, Astrophysics - Solar and Stellar Astrophysics, Physics and Astronomy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], OUTFLOWS, Astrophysics of Galaxies (astro-ph.GA), STRENGTHS
Abstract

We present 850 $��$m polarimetric observations toward the Serpens Main molecular cloud obtained using the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields In STar-forming Region Observations (BISTRO) survey. These observations probe the magnetic field morphology of the Serpens Main molecular cloud on about 6000 au scales, which consists of cores and six filaments with different physical properties such as density and star formation activity. Using the histogram of relative orientation (HRO) technique, we find that magnetic fields are parallel to filaments in less dense filamentary structures where $N_{H_2} < 0.93\times 10^{22}$ cm$^{-2}$ (magnetic fields perpendicular to density gradients), while being perpendicular to filaments (magnetic fields parallel to density gradients) in dense filamentary structures with star formation activity. Moreover, applying the HRO technique to denser core regions, we find that magnetic field orientations change to become perpendicular to density gradients again at $N_{H_2} \approx 4.6 \times 10^{22}$ cm$^{-2}$. This can be interpreted as a signature of core formation. At $N_{H_2} \approx 16 \times 10^{22}$ cm$^{-2}$ magnetic fields change back to being parallel to density gradients once again, which can be understood to be due to magnetic fields being dragged in by infalling material. In addition, we estimate the magnetic field strengths of the filaments ($B_{POS} = 60-300~��$G)) using the Davis-Chandrasekhar-Fermi method and discuss whether the filaments are gravitationally unstable based on magnetic field and turbulence energy densities., 18 pages, accepted for publication in ApJ

Published
2022
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16. The JCMT BISTRO-2 survey : magnetic fields of the massive DR21 filament

Author

Tao-Chung Ching, Keping Qiu, Di Li, Zhiyuan Ren, Shih-Ping Lai, David Berry, Kate Pattle, Ray Furuya, Derek Ward-Thompson, Doug Johnstone, Patrick M. Koch, Chang Won Lee, Thiem Hoang, Tetsuo Hasegawa, Woojin Kwon, Pierre Bastien, Chakali Eswaraiah, Jia-Wei Wang, Kyoung Hee Kim, Jihye Hwang, Archana Soam, A-Ran Lyo, Junhao Liu, Valentin J. M. Le Gouellec, Doris Arzoumanian, Anthony Whitworth, James Di Francesco, Frédérick Poidevin, Tie Liu, Simon Coudé, Mehrnoosh Tahani, Hong-Li Liu, Takashi Onaka, Dalei Li, Motohide Tamura, Zhiwei Chen, Xindi Tang, Florian Kirchschlager, Tyler L. Bourke, Do-Young Byun, Mike Chen, Huei-Ru Vivien Chen, Wen Ping Chen, Jungyeon Cho, Yunhee Choi, Youngwoo Choi, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Y. Sophia Dai, Pham Ngoc Diep, Yasuo Doi, Yan Duan, Hao-Yuan Duan, David Eden, Lapo Fanciullo, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Saeko Hayashi, Martin Houde, Charles L. H. Hull, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Vera Könyves, Ji-hyun Kang, Miju Kang, Janik Karoly, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Jongsoo Kim, Mi-Ryang Kim, Shinyoung Kim, Hyosung Kim, Kee-Tae Kim, Gwanjeong Kim, Jason Kirk, Masato I. N. Kobayashi, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Chi-Yan Law, Sang-Sung Lee, Hyeseung Lee, Jeong-Eun Lee, Chin-Fei Lee, Yong-Hee Lee, Guangxing Li, Hua-bai Li, Sheng-Jun Lin, Sheng-Yuan Liu, Xing Lu, Steve Mairs, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Geumsook Park, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Mark Rawlings, Jonathan Rawlings, Brendan Retter, John Richer, Andrew Rigby, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Ya-Wen Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Hongchi Wang, Jintai Wu, Jinjin Xie, Meng-Zhe Yang, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Chuan-Peng Zhang, Yapeng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Philippe André, C. Darren Dowell, Stewart Eyres, Sam Falle, Jean-François Robitaille, Sven van Loo, National Natural Science Foundation of China, Chinese Academy of Sciences, Natural Sciences and Engineering Research Council of Canada, Ministerio de Ciencia, Innovación y Universidades (España), National Research Foundation of Korea, National Research, Japan Society for the Promotion of Science, Agencia Estatal de Investigación (España), Ching, Tao-Chung [0000-0001-8516-2532], Qiu, Keping [0000-0002-5093-5088], Li, Di [0000-0003-3010-7661], Ren, Zhiyuan [0000-0003-4659-1742], Lai, Shih-Ping [0000-0001-5522-486X], Berry, David [0000-0001-6524-2447], Pattle, Kate [0000-0002-8557-3582], Furuya, Ray [0000-0003-0646-8782], Ward-Thompson, Derek [0000-0003-1140-2761], Johnstone, Doug [0000-0002-6773-459X], Koch, Patrick M [0000-0003-2777-5861], Lee, Chang Won [0000-0002-3179-6334], Hoang, Thiem [0000-0003-2017-0982], Hasegawa, Tetsuo [0000-0003-1853-0184], Kwon, Woojin [0000-0003-4022-4132], Bastien, Pierre [0000-0002-0794-3859], Eswaraiah, Chakali [0000-0003-4761-6139], Wang, Jia-Wei [0000-0002-6668-974X], Kim, Kyoung Hee [0000-0001-9597-7196], Hwang, Jihye [0000-0001-7866-2686], Soam, Archana [0000-0002-6386-2906], Lyo, A-Ran [0000-0002-9907-8427], Liu, Junhao [0000-0002-4774-2998], Le Gouellec, Valentin JM [0000-0002-5714-799X], Arzoumanian, Doris [0000-0002-1959-7201], Whitworth, Anthony [0000-0002-1178-5486], Francesco, James Di [0000-0002-9289-2450], Poidevin, Frédérick [0000-0002-5391-5568], Liu, Tie [0000-0002-5286-2564], Coudé, Simon [0000-0002-0859-0805], Tahani, Mehrnoosh [0000-0001-8749-1436], Liu, Hong-Li [0000-0003-3343-9645], Onaka, Takashi [0000-0002-8234-6747], Tamura, Motohide [0000-0002-6510-0681], Chen, Zhiwei [0000-0003-0849-0692], Tang, Xindi [0000-0002-4154-4309], Kirchschlager, Florian [0000-0002-3036-0184], Bourke, Tyler L [0000-0001-7491-0048], Byun, Do-Young [0000-0003-1157-4109], Chen, Huei-Ru Vivien [0000-0002-9774-1846], Chen, Wen Ping [0000-0003-0262-272X], Cho, Jungyeon [0000-0003-1725-4376], Chrysostomou, Antonio [0000-0002-9583-8644], Chung, Eun Jung [0000-0003-0014-1527], Dai, Y Sophia [0000-0002-7928-416X], Diep, Pham Ngoc [0000-0002-2808-0888], Doi, Yasuo [0000-0001-8746-6548], Duan, Hao-Yuan [0000-0002-7022-4742], Eden, David [0000-0002-5881-3229], Fanciullo, Lapo [0000-0001-9930-9240], Fissel, Laura M [0000-0002-4666-609X], Franzmann, Erica [0000-0003-2142-0357], Friberg, Per [0000-0002-8010-8454], Friesen, Rachel [0000-0001-7594-8128], Fuller, Gary [0000-0001-8509-1818], Gledhill, Tim [0000-0002-2859-4600], Graves, Sarah [0000-0001-9361-5781], Greaves, Jane [0000-0002-3133-413X], Gu, Qilao [0000-0002-2826-1902], Hayashi, Saeko [0000-0001-5026-490X], Houde, Martin [0000-0003-4420-8674], Hull, Charles LH [0000-0002-8975-7573], Inoue, Tsuyoshi [0000-0002-7935-8771], Inutsuka, Shu-ichiro [0000-0003-4366-6518], Jeong, Il-Gyo [0000-0002-5492-6832], Könyves, Vera [0000-0002-3746-1498], Kang, Ji-hyun [0000-0001-7379-6263], Kang, Miju [0000-0002-5016-050X], Karoly, Janik [0000-0001-5996-3600], Kataoka, Akimasa [0000-0003-4562-4119], Kawabata, Koji [0000-0001-6099-9539], Kemper, Francisca [0000-0003-2743-8240], Kim, Jongsoo [0000-0002-1229-0426], Kim, Shinyoung [0000-0001-9333-5608], Kim, Kee-Tae [0000-0003-2412-7092], Kim, Gwanjeong [0000-0003-2011-8172], Kirk, Jason [0000-0002-4552-7477], Kobayashi, Masato IN [0000-0003-3990-1204], Kusune, Takayoshi [0000-0002-9218-9319], Kwon, Jungmi [0000-0003-2815-7774], Lacaille, Kevin [0000-0001-9870-5663], Law, Chi-Yan [0000-0003-1964-970X], Lee, Sang-Sung [0000-0002-6269-594X], Lee, Hyeseung [0000-0003-3465-3213], Lee, Jeong-Eun [0000-0003-3119-2087], Lee, Chin-Fei [0000-0002-3024-5864], Lee, Yong-Hee [0000-0001-6047-701X], Li, Guangxing [0000-0003-3144-1952], Li, Hua-bai [0000-0003-2641-9240], Lin, Sheng-Jun [0000-0002-6868-4483], Liu, Sheng-Yuan [0000-0003-4603-7119], Lu, Xing [0000-0003-2619-9305], Mairs, Steve [0000-0002-6956-0730], Matsumura, Masafumi [0000-0002-6906-0103], Matthews, Brenda [0000-0003-3017-9577], Moriarty-Schieven, Gerald [0000-0002-0393-7822], Nagata, Tetsuya [0000-0001-9264-9015], Nakamura, Fumitaka [0000-0001-5431-2294], Ngoc, Nguyen Bich [0000-0002-5913-5554], Ohashi, Nagayoshi [0000-0003-0998-5064], Park, Geumsook [0000-0001-8467-3736], Parsons, Harriet [0000-0002-6327-3423], Pyo, Tae-Soo [0000-0002-3273-0804], Qian, Lei [0000-0003-0597-0957], Rao, Ramprasad [0000-0002-1407-7944], Rawlings, Mark [0000-0002-6529-202X], Rawlings, Jonathan [0000-0001-5560-1303], Richer, John [0000-0002-9693-6860], Rigby, Andrew [0000-0002-3351-2200], Savini, Giorgio [0000-0003-4449-9416], Shimajiri, Yoshito [0000-0001-9368-3143], Shinnaga, Hiroko [0000-0001-9407-6775], Tang, Ya-Wen [0000-0002-0675-276X], Tomisaka, Kohji [0000-0003-2726-0892], Tram, Le Ngoc [0000-0002-6488-8227], Viti, Serena [0000-0001-8504-8844], Wang, Hongchi [0000-0003-0746-7968], Wu, Jintai [0000-0001-7276-3590], Xie, Jinjin [0000-0002-2738-146X], Yen, Hsi-Wei [0000-0003-1412-893X], Yoo, Hyunju [0000-0002-8578-1728], Yun, Hyeong-Sik [0000-0001-6842-1555], Zhang, Chuan-Peng [0000-0002-4428-3183], Zhang, Yapeng [0000-0002-5102-2096], Zhou, Jianjun [0000-0003-0356-818X], André, Philippe [0000-0002-3413-2293], Falle, Sam [0000-0002-9829-0426], Robitaille, Jean-François [0000-0001-5079-8573], van Loo, Sven [0000-0003-4746-8500], and Apollo - University of Cambridge Repository

Subjects
STAR-FORMING REGIONS, SUBMILLIMETER POLARIZATION, HERSCHEL, FOS: Physical sciences, Astronomy and Astrophysics, MU-M POLARIZATION, MOLECULAR CLOUD, Astrophysics - Astrophysics of Galaxies, 1ST, Astrophysics - Solar and Stellar Astrophysics, Physics and Astronomy, 5101 Astronomical Sciences, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SCUBA-2, GOULD BELT SURVEY, DUST EMISSION, 51 Physical Sciences, Solar and Stellar Astrophysics (astro-ph.SR), FAR-INFRARED POLARIMETRY
Abstract

Tao-Chung Ching et al., We present 850 μm dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1–10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6–1.0 mG in the DR21 filament and ∼0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments., This work is supported by National Natural Science Foundation of China (NSFC) grant Nos. 11988101, U1931117, 11725313, and 12073061 and the CAS International Partnership Program of Chinese Academy of Sciences grant No. 114A11KYSB20160008. T.-C.C. is funded by Chinese Academy of Sciences Taiwan Young Talent Program grant No. 2018TW2JB0002. T.-C.C. and C.E. were supported by Special Funding for Advanced Users, budgeted and administrated by Center for Astronomical Mega-Science (CAMS), Chinese Academy of Sciences. K.P. is a Royal Society University Research Fellow, supported by grant No. URF\R1\211322. D.J. is supported by the National Research Council of Canada and by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant. P.M.K. is supported by the Ministry of Science and Technology (MoST) in Taiwan through grants 109-2112-M-001-022 and 110-2112-M-001-057. C.W.L. is supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2019R1A2C1010851), and by the Korea Astronomy and Space Science Institute grant funded by the Korea government (MSIT; Project No. 2022-1-840-05). T.H. is supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) through the Mid-career Research Program (2019R1A2C1087045). W.K. was supported by the NRF grant funded by the MSIT (2021R1F1A1061794). C.E. acknowledges the financial support from grant RJF/2020/000071 as a part of Ramanujan Fellowship awarded by the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Govt. of India. F.P. acknowledges support from the Spanish State Research Agency (AEI) under grant No. PID2019-105552RB-C43. M.T. is supported by JSPS KAKENHI grant Nos. 18H05442, 15H02063, and 22000005. J.K. is supported by JSPS KAKENHI grant No. 19K14775. L.F. and F.K. acknowledge the support by the MoST in Taiwan through grant 107-2119-M-001-031-MY3 and Academia Sinica through grant AS-IA-106-M03. L.F. acknowledges the support by the MoST in Taiwan through grants 111-2811-M-005-007 and 109-2112-M-005-003-MY3. C.L.H.H. acknowledges the support of the NAOJ Fellowship and JSPS KAKENHI grants 18K13586 and 20K14527. F.K. is supported by the Spanish program Unidad de Excelencia María de Maeztu CEX2020-001058-M, financed by MCIN/AEI/10.13039/501100011033. K.Q. is partially supported by National Key R&D Program of China No. 2022YFA1603100, and acknowledges the National Natural Science Foundation of China (NSFC) grant U1731237. S.P.L. acknowledges grants from the Ministry of Science and Technology of Taiwan 106-2119-M-007-021-MY3 and 109-2112-M-007-010-MY3. Y.D. acknowledges the support of JSPS KAKENHI grants 25247016 and 18H01250. Y.S.D. is supported by the National Key R&D Program of China for grant No. 2022YFA1605300, and NSFC grants Nos. 12273051, 11933003.

Published
2022

17. The JCMT BISTRO survey: A spiral magnetic field in a hub-filament structure, monoceros R2

Author

Jihye Hwang, Jongsoo Kim, Kate Pattle, Chang Won Lee, Patrick M. Koch, Doug Johnstone, Kohji Tomisaka, Anthony Whitworth, Ray S. Furuya, Ji-hyun Kang, A-Ran Lyo, Eun Jung Chung, Doris Arzoumanian, Geumsook Park, Woojin Kwon, Shinyoung Kim, Motohide Tamura, Jungmi Kwon, Archana Soam, Ilseung Han, Thiem Hoang, Kyoung Hee Kim, Takashi Onaka, Chakali Eswaraiah, Derek Ward-Thompson, Hong-Li Liu, Xindi Tang, Wen Ping Chen, Masafumi Matsumura, Thuong Duc Hoang, Zhiwei Chen, Valentin J. M. Le Gouellec, Florian Kirchschlager, Frédérick Poidevin, Pierre Bastien, Keping Qiu, Tetsuo Hasegawa, Shih-Ping Lai, Do-Young Byun, Jungyeon Cho, Minho Choi, Youngwoo Choi, Yunhee Choi, Il-Gyo Jeong, Miju Kang, Hyosung Kim, Kee-Tae Kim, Jeong-Eun Lee, Sang-Sung Lee, Yong-Hee Lee, Hyeseung Lee, Mi-Ryang Kim, Hyunju Yoo, Hyeong-Sik Yun, Mike Chen, James Di Francesco, Jason Fiege, Laura M. Fissel, Erica Franzmann, Martin Houde, Kevin Lacaille, Brenda Matthews, Sarah Sadavoy, Gerald Moriarty-Schieven, Mehrnoosh Tahani, Tao-Chung Ching, Y. Sophia Dai, Yan Duan, Qilao Gu, Chi-Yan Law, Dalei Li, Di Li, Guangxing Li, Hua-bai Li, Tie Liu, Xing Lu, Lei Qian, Hongchi Wang, Jintai Wu, Jinjin Xie, Jinghua Yuan, Chuan-Peng Zhang, Guoyin Zhang, Yapeng Zhang, Jianjun Zhou, Lei Zhu, David Berry, Per Friberg, Sarah Graves, Junhao Liu, Steve Mairs, Harriet Parsons, Mark Rawlings, Yasuo Doi, Saeko Hayashi, Charles L. H. Hull, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Akimasa Kataoka, Koji Kawabata, Gwanjeong Kim, Masato I. N. Kobayashi, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Tae-Soo Pyo, Hiro Saito, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Yusuke Tsukamoto, Tetsuya Zenko, Huei-Ru Vivien Chen, Hao-Yuan Duan, Lapo Fanciullo, Francisca Kemper, Chin-Fei Lee, Sheng-Jun Lin, Sheng-Yuan Liu, Nagayoshi Ohashi, Ramprasad Rao, Ya-Wen Tang, Jia-Wei Wang, Meng-Zhe Yang, Hsi-Wei Yen, Tyler L. Bourke, Antonio Chrysostomou, Victor Debattista, David Eden, Stewart Eyres, Sam Falle, Gary Fuller, Tim Gledhill, Jane Greaves, Matt Griffin, Jennifer Hatchell, Janik Karoly, Jason Kirk, Vera Könyves, Steven Longmore, Sven van Loo, Ilse de Looze, Nicolas Peretto, Felix Priestley, Jonathan Rawlings, Brendan Retter, John Richer, Andrew Rigby, Giorgio Savini, Anna Scaife, Serena Viti, Pham Ngoc Diep, Nguyen Bich Ngoc, Le Ngoc Tram, Philippe André, Simon Coudé, C. Darren Dowell, Rachel Friesen, Jean-Franćois Robitaille, National Research Foundation of Korea, Japan Society for the Promotion of Science, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), and National Science Foundation (US)

Subjects
POLARIZATION, CLOUDS, FOS: Physical sciences, Astronomy and Astrophysics, REGIONS, Astrophysics - Astrophysics of Galaxies, 1ST, DENSE CORES, MODEL, Physics and Astronomy, GRAVITY, POL-2, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SCUBA-2
Abstract

Hwang et al., We present and analyze observations of polarized dust emission at 850 μm toward the central 1 × 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis–Chandrasekhar–Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from Herschel data and the C18O (J = 3 − 2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 ± 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 ± 0.02. Additionally, the mean Alfvén Mach number is 0.35 ± 0.01. This suggests that, in Mon R2, the magnetic fields provide resistance against large-scale gravitational collapse, and the magnetic pressure exceeds the turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically subcritical., J.H. is supported by the University of Science and Technology (UST) Overseas Training Program 2022, funded by the University of Science and Technology, Korea (No. 2022-017). K.P. is a Royal Society University Research Fellow, supported by grant number URF\R1\211322. C.W.L. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF- 2019R1A2C1010851), and by the Korea Astronomy and Space Science Institute grant funded by the Korea government (MSIT; Project No. 2022-1-840-05). D.J. and J.d.F. are supported by the National Research Council of Canada and by Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grants. G.P. is supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF; 2020R1A6A3A01100208) W.K. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; NRF-2021R1F1A1061794). M.T. is supported by JSPS KAKENHI grant Nos. 18H05442, 15H02063, and 22000005. J.K. is supported by JSPS KAKENHI grant No. 19K14775. M.M. is supported by JSPS KAKENHI grant No. 20K03276. F.P. acknowledges support from the Spanish State Research Agency Agencia Estatal de Investigación (AEI) under grant number PID2019-105552RB-C43. S.P.L., H.Y.D., S.J.L., and M.Z.Y. acknowledge grants from the Ministry of Science and Technology of Taiwan 106-2119-M-007-021-MY3 and 109-2112-M-007-010-MY3. C.E. acknowledges the financial support from grant RJF/2020/000071 as a part of a Ramanujan Fellowship awarded by Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Govt. of India. L.F. and F.K. acknowledge support from the Ministry of Science and Technology of Taiwan, under grant No. MoST107-2119-M-001-031- MY3 and from Academia Sinica under grant No. AS-IA-106-M03. L.F. acknowledges the support by the MoST in Taiwan through grants 111-2811-M-005-007 and 109-2112-M-005-003-MY3. F.K. acknowledges support from the Spanish program Unidad de Excelencia María de Maeztu CEX2020-001058-M, financed by MCIN/AEI/10.13039/501100011033. Y.S.D. would like to acknowledge the support from NSFC grants 12273051 and 10878003. M.R. is supported by the international Gemini Observatory, a program of NSFs NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic of Korea, and the United States of America. The JCMT 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 Operation, Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments, budgeted from the Ministry of Finance of China. 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. Additional funds for the construction of SCUBA-2 were provided by the Canada Foundation for Innovation.

Published
2022

18. The JCMT BISTRO Survey: An 850/450$\mu$m Polarization Study of NGC 2071IR in OrionB

Author

A-Ran Lyo, Jongsoo Kim, Sarah Sadavoy, Doug Johnstone, David Berry, Kate Pattle, Woojin Kwon, Pierre Bastien, Takashi Onaka, James Di Francesco, Ji-Hyun Kang, Ray Furuya, Charles L. H. Hull, Motohide Tamura, Patrick M. Koch, Derek Ward-Thompson, Tetsuo Hasegawa, Thiem Hoang, Doris Arzoumanian, Chang Won Lee, Chin-Fei Lee, Do-Young Byun, Florian Kirchschlager, Yasuo Doi, Kee-Tae Kim, Jihye Hwang, Pham Ngoc Diep, Lapo Fanciullo, Sang-Sung Lee, Geumsook Park, Hyunju Yoo, Eun Jung Chung, Anthony Whitworth, Steve Mairs, Archana Soam, Tie Liu, Xindi Tang, Simon Coudé, Philippe André, Tyler L. Bourke, Huei-Ru Vivien Chen, Zhiwei Chen, Wen Ping Chen, Mike Chen, Tao-Chung Ching, Jungyeon Cho, Minho Choi, Yunhee Choi, Antonio Chrysostomou, Sophia Dai, C. Darren Dowell, Hao-Yuan Duan, Yan Duan, David Eden, Chakali Eswaraiah, Stewart Eyres, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, Gary Fuller, Tim Gledhill, Sarah Graves, Jane Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Jannifer Hatchell, Saeko Hayashi, Martin Houde, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Miju Kang, Akimasa Kataoka, Koji Kawabata, Francisca Kemper, Gwanjeong Kim, Mi-Ryang Kim, Shinyoung Kim, Kyoung Hee Kim, Jason Kirk, Masato I. N. Kobayashi, Vera Könyves, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, Shih-Ping Lai, Chi-Yan Law, Jeong-Eun Lee, Yong-Hee Lee, Hyeseung Lee, Dalei Li, Di Li, Hua-Bai Li, Hong-Li Liu, Junhao Liu, Sheng-Yuan Liu, Xing Lu, Masafumi Matsumura, Brenda Matthews, Gerald Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi, Harriet Parsons, Nicolas Peretto, Felix Priestley, Tae-soo Pyo, Lei Qian, Keping Qiu, Ramprasad Rao, Jonathan Rawlings, Mark G. Rawlings, Brendan Retter, John Richer, Andrew Rigby, Hiro Saito, Giorgio Savini, Anna Scaife, Masumichi Seta, Yoshito Shimajiri, Hiroko Shinnaga, Mehrnoosh Tahani, Ya-Wen Tang, Kohji Tomisaka, Le Ngoc Tram, Yusuke Tsukamoto, Serena Viti, Jia-Wei Wang, Hongchi Wang, Jinjin Xie, Hsi-Wei Yen, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Guoyin Zhang, Chuan-Peng Zhang, Yapeng Zhang, Jianjun Zhou, Lei Zhu, Ilse de Looze, Sam Falle, Jean-François Robitaille, Sven van Loo, Lyo, A-Ran [0000-0002-9907-8427], Kim, Jongsoo [0000-0002-1229-0426], Johnstone, Doug [0000-0002-6773-459X], Pattle, Kate [0000-0002-8557-3582], Kwon, Woojin [0000-0003-4022-4132], Bastien, Pierre [0000-0002-0794-3859], Onaka, Takashi [0000-0002-8234-6747], Kang, Ji-Hyun [0000-0001-7379-6263], Furuya, Ray [0000-0003-0646-8782], Hull, Charles L. H. [0000-0002-8975-7573], Tamura, Motohide [0000-0002-6510-0681], Koch, Patrick M. [0000-0003-2777-5861], Ward-Thompson, Derek [0000-0003-1140-2761], Hoang, Thiem [0000-0003-2017-0982], Arzoumanian, Doris [0000-0002-1959-7201], Lee, Chin-Fei [0000-0002-3024-5864], Byun, Do-Young [0000-0003-1157-4109], Kirchschlager, Florian [0000-0002-3036-0184], Doi, Yasuo [0000-0001-8746-6548], Kim, Kee-Tae [0000-0003-2412-7092], Hwang, Jihye [0000-0001-7866-2686], Lee, Sang-Sung [0000-0002-6269-594X], Park, Geumsook [0000-0001-8467-3736], Yoo, Hyunju [0000-0002-8578-1728], Chung, Eun Jung [0000-0003-0014-1527], Mairs, Steve [0000-0002-6956-0730], Soam, Archana [0000-0002-6386-2906], Liu, Tie [0000-0002-5286-2564], Tang, Xindi [0000-0002-4154-4309], Coudé, Simon [0000-0002-0859-0805], André, Philippe [0000-0002-3413-2293], Bourke, Tyler L. [0000-0001-7491-0048], Chen, Zhiwei [0000-0003-0849-0692], Ping Chen, Wen [0000-0002-5519-0628], Ching, Tao-Chung [0000-0001-8516-2532], Cho, Jungyeon [0000-0003-1725-4376], Chrysostomou, Antonio [0000-0002-9583-8644], Eden, David [0000-0002-5881-3229], Franzmann, Erica [0000-0003-2142-0357], Friberg, Per [0000-0002-8010-8454], Friesen, Rachel [0000-0001-7594-8128], Fuller, Gary [0000-0001-8509-1818], Gledhill, Tim [0000-0002-2859-4600], Graves, Sarah [0000-0001-9361-5781], Gu, Qilao [0000-0002-2826-1902], Hatchell, Jannifer [0000-0002-4870-2760], Houde, Martin [0000-0003-4420-8674], Inoue, Tsuyoshi [0000-0002-7935-8771], Inutsuka, Shu-ichiro [0000-0003-4366-6518], Iwasaki, Kazunari [0000-0002-2707-7548], Kang, Miju [0000-0002-5016-050X], Kataoka, Akimasa [0000-0003-4562-4119], Kawabata, Koji [0000-0001-6099-9539], Kemper, Francisca [0000-0003-2743-8240], Kim, Gwanjeong [0000-0003-2011-8172], Kim, Mi-Ryang [0000-0002-1408-7747], Kim, Shinyoung [0000-0001-9333-5608], Kirk, Jason [0000-0002-4552-7477], Kobayashi, Masato I. N. [0000-0003-3990-1204], Könyves, Vera [0000-0002-3746-1498], Kusune, Takayoshi [0000-0002-9218-9319], Kwon, Jungmi [0000-0003-2815-7774], Lacaille, Kevin [0000-0001-9870-5663], Lai, Shih-Ping [0000-0001-5522-486X], Law, Chi-Yan [0000-0003-1964-970X], Lee, Jeong-Eun [0000-0003-3119-2087], Lee, Yong-Hee [0000-0001-6047-701X], Lee, Hyeseung [0000-0003-3465-3213], Li, Di [0000-0003-3010-7661], Li, Hua-Bai [0000-0003-2641-9240], Liu, Junhao [0000-0002-4774-2998], Liu, Sheng-Yuan [0000-0003-4603-7119], Lu, Xing [0000-0003-2619-9305], Matsumura, Masafumi [0000-0002-6906-0103], Matthews, Brenda [0000-0003-3017-9577], Moriarty-Schieven, Gerald [0000-0002-0393-7822], Nagata, Tetsuya [0000-0001-9264-9015], Nakamura, Fumitaka [0000-0001-5431-2294], Ohashi, Nagayoshi [0000-0003-0998-5064], Parsons, Harriet [0000-0002-6327-3423], Pyo, Tae-soo [0000-0002-3273-0804], Qian, Lei [0000-0003-0597-0957], Qiu, Keping [0000-0002-5093-5088], Rao, Ramprasad [0000-0002-1407-7944], Rawlings, Jonathan [0000-0001-5560-1303], Rawlings, Mark G. [0000-0002-6529-202X], Richer, John [0000-0002-9693-6860], Rigby, Andrew [0000-0002-3351-2200], Savini, Giorgio [0000-0003-4449-9416], Shimajiri, Yoshito [0000-0001-9368-3143], Shinnaga, Hiroko [0000-0001-9407-6775], Tang, Ya-Wen [0000-0002-0675-276X], Tomisaka, Kohji [0000-0003-2726-0892], Tram, Le Ngoc [0000-0002-6488-8227], Viti, Serena [0000-0001-8504-8844], Wang, Jia-Wei [0000-0002-6668-974X], Wang, Hongchi [0000-0003-0746-7968], Yen, Hsi-Wei [0000-0003-1412-893X], Yun, Hyeong-Sik [0000-0001-6842-1555], Zhang, Chuan-Peng [0000-0002-4428-3183], and Apollo - University of Cambridge Repository

Subjects
Young stellar object, FAR-INFRARED POLARIZATION, Astrophysics, F500, IMAGING POLARIMETRY, MAGNETIC-FIELDS, Gravitational energy, STAR-FORMATION, interstellar magnetic fields, Bipolar outflow, SCUBA-2, FORMING MOLECULAR CLOUDS, GOULD BELT SURVEY, James Clerk Maxwell Telescope, polarimetry, Physics, interstellar medium, SUBMILLIMETER POLARIZATION, Magnetic energy, Center (category theory), Interstellar Matter and the Local Universe, CORES, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, Physics and Astronomy, BIPOLAR OUTFLOW, Space and Planetary Science, star forming regions
Abstract

We present the results of simultaneous 450 $\mu$m and 850 $\mu$m polarization observations toward the massive star forming region NGC 2071IR, a target of the BISTRO (B-fields in Star-Forming Region Observations) Survey, using the POL-2 polarimeter and SCUBA-2 camera mounted on the James Clerk Maxwell Telescope. We find a pinched magnetic field morphology in the central dense core region, which could be due to a rotating toroidal disk-like structure and a bipolar outflow originating from the central young stellar object, IRS 3. Using the modified Davis-Chandrasekhar-Fermi method, we obtain a plane-of-sky magnetic field strength of 563$\pm$421 $\mu$G in the central $\sim$0.12 pc region from 850 $\mu$m polarization data. The corresponding magnetic energy density of 2.04$\times$10$^{-8}$ erg cm$^{-3}$ is comparable to the turbulent and gravitational energy densities in the region. We find that the magnetic field direction is very well aligned with the whole of the IRS 3 bipolar outflow structure. We find that the median value of polarization fractions, 3.0 \%, at 450 $\mu$m in the central 3 arcminute region, which is larger than the median value of 1.2 \% at 850 $\mu$m. The trend could be due to the better alignment of warmer dust in the strong radiation environment. We also find that polarization fractions decrease with intensity at both wavelengths, with slopes, determined by fitting a Rician noise model, of $0.59 \pm 0.03$ at 450 $\mu$m and $0.36 \pm 0.04$ at 850 $\mu$m, respectively. We think that the shallow slope at 850 $\mu$m is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects., Comment: 17 pages, 11 figures, 4 tables

Published
2021

19. The JCMT BISTRO Survey: Revealing the Diverse Magnetic Field Morphologies in Taurus Dense Cores with Sensitive Submillimeter Polarimetry

Author

A-Ran Lyo, Nguyen Bich Ngoc, Jean-François Robitaille, L. M. Fissel, Jonathan Rawlings, Yapeng Zhang, Andrew Rigby, Matthew Joseph Griffin, Tetsuo Hasegawa, Ji-hyun Kang, Sam Falle, Jongsoo Kim, Jason Fiege, Il-Gyo Jeong, Ya-Wen Tang, Kate Pattle, Zhiwei Chen, Rachel Friesen, Florian Kirchschlager, Doris Arzoumanian, Chang Won Lee, Jennifer Hatchell, Ramprasad Rao, Shih-Ping Lai, Sung-ju Kang, Di Li, Kevin Lacaille, Keping Qiu, Eun Jung Chung, Dalei Li, Gerald H. Moriarty-Schieven, Archana Soam, Anthony Peter Whitworth, Shu-ichiro Inutsuka, Hua-bai Li, Per Friberg, Doug Johnstone, Lei Qian, Thiem Hoang, Kazunari Iwasaki, Lapo Fanciullo, Pham Ngoc Diep, Sarah Graves, Masato I. N. Kobayashi, Nicolas Peretto, Harriet Parsons, Jungyeon Cho, Hiroyuki Nakanishi, Chuan-Peng Zhang, Y. Shimajiri, Martin Houde, Fumitaka Nakamura, John Richer, Kee-Tae Kim, Serena Viti, Derek Ward-Thompson, Jianjun Zhou, Jason M. Kirk, Geumsook Park, Nagayoshi Ohashi, Erica Franzmann, C. Darren Dowell, Woojin Kwon, Mi-Ryang Kim, Sven Van Loo, Tyler Bourke, Mark G. Rawlings, Ilseung Han, Masumichi Seta, Junhao Liu, Motohide Tamura, Minho Choi, Jinghua Yuan, Hao-Yuan Duan, Hong-Li Liu, Wen Ping Chen, Jinjin Xie, Tie Liu, David Eden, S. P. S. Eyres, Yan Duan, Miju Kang, Charles L. H. Hull, Le Ngoc Tram, Koji S. Kawabata, Giorgio Savini, Sophia Dai, Masafumi Matsumura, Chakali Eswaraiah, Tae-Soo Pyo, Francisca Kemper, Yong-Hee Lee, Jia-Wei Wang, Saeko S. Hayashi, Yusuke Tsukamoto, Hsi-Wei Yen, Hyunju Yoo, Sang-Sung Lee, Antonio Chrysostomou, Gwanjeong Kim, Huei-Ru Vivien Chen, Brenda C. Matthews, S. Coude, Qilao Gu, Yasuo Doi, Guoyin Zhang, Tao-Chung Ching, Hiro Saito, Hongchi Wang, Ilse De Looze, Sheng-Yuan Liu, Philippe André, Jihye Hwang, Hiroko Shinnaga, David Berry, Hyeong-Sik Yun, Jane Greaves, Vera Konyves, Do-Young Byun, Ray S. Furuya, Mike Chen, Tim Gledhill, Kyoung Hee Kim, Tetsuya Zenko, Steve Mairs, Jungmi Kwon, Takayoshi Kusune, Chin-Fei Lee, Tetsuya Nagata, Tsuyoshi Inoue, Brendan Retter, Xing Lu, Patrick M. Koch, Yunhee Choi, Chi-Yan Law, Gary A. Fuller, Mehrnoosh Tahani, Takashi Onaka, Pierre Bastien, Xindi Tang, Anna M. M. Scaife, Kohji Tomisaka, Lei Zhu, Sarah Sadavoy, Akimasa Kataoka, Chakali, Eswaraiah [0000-0003-4761-6139], Furuya, Ray S. [0000-0003-0646-8782], Hasegawa, Tetsuo [0000-0003-1853-0184], Ward-Thompson, Derek [0000-0003-1140-2761], Qiu, Keping [0000-0002-5093-5088], Ohashi, Nagayoshi [0000-0003-0998-5064], Pattle, Kate [0000-0002-8557-3582], Sadavoy, Sarah [0000-0001-7474-6874], Hull, Charles L. H. [0000-0002-8975-7573], Berry, David [0000-0001-6524-2447], Doi, Yasuo [0000-0001-8746-6548], Ching, Tao-Chung [0000-0001-8516-2532], Lai, Shih-Ping [0000-0001-5522-486X], Wang, Jia-Wei [0000-0002-6668-974X], Koch, Patrick M. [0000-0003-2777-5861], Kwon, Jungmi [0000-0003-2815-7774], Kwon, Woojin [0000-0003-4022-4132], Bastien, Pierre [0000-0002-0794-3859], Arzoumanian, Doris [0000-0002-1959-7201], Coudé, Simon [0000-0002-0859-0805], Soam, Archana [0000-0002-6386-2906], Fanciullo, Lapo [0000-0001-9930-9240], Yen, Hsi-Wei [0000-0003-1412-893X], Liu, Junhao [0000-0002-4774-2998], Hoang, Thiem [0000-0003-2017-0982], Ping Chen, Wen [0000-0003-0262-272X], Shimajiri, Yoshito [0000-0001-9368-3143], Liu, Tie [0000-0002-5286-2564], Chen, Zhiwei [0000-0003-0849-0692], Li, Hua-bai [0000-0003-2641-9240], Lyo, A-Ran [0000-0002-9907-8427], Hwang, Jihye [0000-0001-7866-2686], Johnstone, Doug [0000-0002-6773-459X], Rao, Ramprasad [0000-0002-1407-7944], Bich Ngoc, Nguyen [0000-0002-5913-5554], Ngoc Diep, Pham [0000-0002-2808-0888], Mairs, Steve [0000-0002-6956-0730], Parsons, Harriet [0000-0002-6327-3423], Tamura, Motohide [0000-0002-6510-0681], Tahani, Mehrnoosh [0000-0001-8749-1436], Vivien Chen, Huei-Ru [0000-0002-9774-1846], Nakamura, Fumitaka [0000-0001-5431-2294], Shinnaga, Hiroko [0000-0001-9407-6775], Tang, Ya-Wen [0000-0002-0675-276X], Cho, Jungyeon [0000-0003-1725-4376], Won Lee, Chang [0000-0002-3179-6334], Inutsuka, Shu-ichiro [0000-0003-4366-6518], Iwasaki, Kazunari [0000-0002-2707-7548], Qian, Lei [0000-0003-0597-0957], Xie, Jinjin [0000-0002-2738-146X], Liu, Hong-Li [0000-0003-3343-9645], Zhang, Chuan-Peng [0000-0002-4428-3183], Zhou, Jianjun [0000-0003-0356-818X], André, Philippe [0000-0002-3413-2293], Liu, Sheng-Yuan [0000-0003-4603-7119], Lu, Xing [0000-0003-2619-9305], Bourke, Tyler L. [0000-0001-7491-0048], Byun, Do-Young [0000-0003-1157-4109], Eden, David [0000-0002-5881-3229], Matthews, Brenda [0000-0003-3017-9577], Fissel, Laura M. [0000-0002-4666-609X], Kim, Kee-Tae [0000-0003-2412-7092], Lee, Chin-Fei [0000-0002-3024-5864], Kim, Jongsoo [0000-0002-1229-0426], Pyo, Tae-Soo [0000-0002-3273-0804], Chrysostomou, Antonio [0000-0002-9583-8644], Jung Chung, Eun [0000-0003-0014-1527], Ngoc Tram, Le [0000-0002-6488-8227], Franzmann, Erica [0000-0003-2142-0357], Friberg, Per [0000-0002-8010-8454], Friesen, Rachel [0000-0001-7594-8128], Fuller, Gary [0000-0001-8509-1818], Gledhill, Tim [0000-0002-2859-4600], Graves, Sarah [0000-0001-9361-5781], Griffin, Matt [0000-0002-0033-177X], Gu, Qilao [0000-0002-2826-1902], Hatchell, Jennifer [0000-0002-4870-2760], Houde, Martin [0000-0003-4420-8674], Kawabata, Koji [0000-0001-6099-9539], Jeong, Il-Gyo [0000-0002-5492-6832], Kang, Ji-hyun [0000-0001-7379-6263], Kang, Sung-ju [0000-0002-5004-7216], Kang, Miju [0000-0002-5016-050X], Kataoka, Akimasa [0000-0003-4562-4119], Kemper, Francisca [0000-0003-2743-8240], Rawlings, Mark [0000-0002-6529-202X], Rawlings, Jonathan [0000-0001-5560-1303], Richer, John [0000-0002-9693-6860], Rigby, Andrew [0000-0002-3351-2200], Savini, Giorgio [0000-0003-4449-9416], Scaife, Anna [0000-0002-5364-2301], Kim, Gwanjeong [0000-0003-2011-8172], Hee Kim, Kyoung [0000-0001-9597-7196], Kim, Mi-Ryang [0000-0002-1408-7747], Kirchschlager, Florian [0000-0002-3036-0184], Kirk, Jason [0000-0002-4552-7477], Kobayashi, Masato I. N. [0000-0003-3990-1204], Konyves, Vera [0000-0002-3746-1498], Kusune, Takayoshi [0000-0002-9218-9319], Lacaille, Kevin [0000-0001-9870-5663], Law, Chi-Yan [0000-0003-1964-970X], Lee, Sang-Sung [0000-0002-6269-594X], Lee, Yong-Hee [0000-0001-6047-701X], Matsumura, Masafumi [0000-0002-6906-0103], Moriarty-Schieven, Gerald [0000-0002-0393-7822], Nagata, Tetsuya [0000-0001-9264-9015], Onaka, Takashi [0000-0002-8234-6747], Park, Geumsook [0000-0001-8467-3736], Tang, Xindi [0000-0002-4154-4309], Tomisaka, Kohji [0000-0003-2726-0892], Viti, Serena [0000-0001-8504-8844], Wang, Hongchi [0000-0003-0746-7968], Yoo, Hyunju [0000-0002-8578-1728], Zhang, Yapeng [0000-0002-5102-2096], Falle, Sam [0000-0002-9829-0426], Robitaille, Jean-François [0000-0001-5079-8573], Apollo - University of Cambridge Repository, Eswaraiah, Chakali [0000-0003-4761-6139], Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
low mass stars, 010504 meteorology & atmospheric sciences, Continuum (design consultancy), AXISYMMETRICAL CLOUD CORES, Astrophysics, F500, MOLECULAR CLOUD, IMAGING POLARIMETRY, 01 natural sciences, AMBIPOLAR-DIFFUSION, STAR-FORMATION, interstellar magnetic fields, Protein filament, CONTRACTION, 0103 physical sciences, SCUBA-2, COLLAPSE, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, 0105 earth and related environmental sciences, dust continuum emission, polarimetry, Physics, Ambipolar diffusion, Star formation, F510, dense interstellar clouds, Astronomy and Astrophysics, GOULD BELT, Magnetic flux, Magnetic field, DARK CLOUDS, Core (optical fiber), Physics and Astronomy, [SDU]Sciences of the Universe [physics], Space and Planetary Science
Abstract

We have obtained sensitive dust continuum polarization observations at 850 μm in the B213 region of Taurus using POL-2 on SCUBA-2 at the James Clerk Maxwell Telescope as part of the B-fields in STar-forming Region Observations (BISTRO) survey. These observations allow us to probe magnetic field (B-field) at high spatial resolution (∼2000 au or ∼0.01 pc at 140 pc) in two protostellar cores (K04166 and K04169) and one prestellar core (Miz-8b) that lie within the B213 filament. Using the Davis–Chandrasekhar–Fermi method, we estimate the B-field strengths in K04166, K04169, and Miz-8b to be 38 ± 14, 44 ± 16, and 12 ± 5 μG, respectively. These cores show distinct mean B-field orientations. The B-field in K04166 is well ordered and aligned parallel to the orientations of the core minor axis, outflows, core rotation axis, and large-scale uniform B-field, in accordance with magnetically regulated star formation via ambipolar diffusion taking place in K04166. The B-field in K04169 is found to be ordered but oriented nearly perpendicular to the core minor axis and large-scale B-field and not well correlated with other axes. In contrast, Miz-8b exhibits a disordered B-field that shows no preferred alignment with the core minor axis or large-scale field. We found that only one core, K04166, retains a memory of the large-scale uniform B-field. The other two cores, K04169 and Miz-8b, are decoupled from the large-scale field. Such a complex B-field configuration could be caused by gas inflow onto the filament, even in the presence of a substantial magnetic flux.

Published
2021
Full Text
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20. Observations of magnetic fields surrounding LkH$\alpha$ 101 taken by the BISTRO survey with JCMT-POL-2

Author

Fumitaka Nakamura, Lapo Fanciullo, Eun Jung Chung, Yan Duan, Sophia Dai, Saeko S. Hayashi, Sven Van Loo, Dalei Li, Nicolas Peretto, Ray S. Furuya, Miju Kang, Tyler Bourke, Mark G. Rawlings, John Richer, Archana Soam, Kee-Tae Kim, Anna M. M. Scaife, Kohji Tomisaka, Jason M. Kirk, Hiroko Shinnaga, Anthony Peter Whitworth, David Berry, Chakali Eswaraiah, Le Ngoc Tram, Masumichi Seta, Serena Viti, Geumsook Park, Sheng-Yuan Liu, Nagayoshi Ohashi, Antonio Chrysostomou, Yunhee Choi, Tsuyoshi Inoue, Tae-Soo Pyo, Hongchi Wang, Pham Ngoc Diep, Erica Franzmann, Matthew Joseph Griffin, Francisca Kemper, Kyoung Hee Kim, Tetsuo Hasegawa, Hiro Saito, C. Darren Dowell, Philippe André, Chuan-Peng Zhang, Yong-Hee Lee, Sung-ju Kang, Sam Falle, Mike Chen, Gary A. Fuller, Jongsoo Kim, Chi-Yan Law, Mi-Ryang Kim, Tetsuya Zenko, Thiem Hoang, Tim Gledhill, A-Ran Lyo, Gerald Moriarty-Schieven, Nguyen Bich Ngoc, Takashi Onaka, Pierre Bastien, Motohide Tamura, Harriet Parsons, Hua-bai Li, Takayoshi Kusune, Jungmi Kwon, Xindi Tang, Zhiwei Chen, Tetsuya Nagata, Chin-Fei Lee, Brendan Retter, Guoyin Zhang, Martin Houde, Ji-hyun Kang, Jason Fiege, Il-Gyo Jeong, James Di Francesco, Jane Greaves, Vera Konyves, Do-Young Byun, Junhao Liu, Chang Won Lee, Jia-Wei Wang, Qilao Gu, Patrick M. Koch, Kate Pattle, Shu-ichiro Inutsuka, Derek Ward-Thompson, Florian Kirchschlager, Doris Arzoumanian, Hyeong-Sik Yun, Jianjun Zhou, Lei Zhu, Yusuke Tsukamoto, Charles L. H. Hull, Koji S. Kawabata, Minho Choi, Hyeseung Lee, Yasuo Doi, Kevin Lacaille, Brenda C. Matthews, Ilseung Han, Per Friberg, S. Coude, Jennifer Hatchell, Ramprasad Rao, Di Li, Jihye Hwang, Jean-François Robitaille, L. M. Fissel, Jonathan Rawlings, Gwanjeong Kim, Huei-Ru Vivien Chen, Sarah Sadavoy, Giorgio Savini, Yapeng Zhang, Shih-Ping Lai, Akimasa Kataoka, Xing Lu, Doug Johnstone, Steve Mairs, Andrew Rigby, Mehrnoosh Tahani, Masato I. N. Kobayashi, Hsi-Wei Yen, Hyunju Yoo, Tie Liu, Woojin Kwon, S. L. Kim, Hao-Yuan Duan, Hong-Li Liu, Sang-Sung Lee, Jinjin Xie, Masafumi Matsumura, Tao-Chung Ching, David Eden, Ilse De Looze, Jeong-Eun Lee, S. P. S. Eyres, Rachel Friesen, Jinghua Yuan, Keping Qiu, Sarah Graves, Jungyeon Cho, Wen Ping Chen, Hiroyuki Nakanishi, Y. Shimajiri, Lei Qian, Kazunari Iwasaki, and Ya-Wen Tang

Subjects
Physics, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, molecular clouds, Astrophysics, F500, Polarization (waves), 01 natural sciences, Astrophysics - Astrophysics of Galaxies, star formation, Redshift, interstellar magnetic fields, Magnetic field, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Gravitational collapse, Radiative transfer, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics
Abstract

We report the first high spatial resolution measurement of magnetic fields surrounding LkH$\alpha$ 101, a part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 $\mu$m is found to be mostly associated with the red-shifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of $B_{\rm POS}\sim 115$ $\mathrm{\mu}$G. The mass-to-magnetic-flux ratio in critical value units, $\lambda\sim0.3$, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkH$\alpha$ 101 region is sub-critical and the magnetic field is strong enough to prevent gravitational collapse. The inferred $\delta B/B_0\sim 0.3$ implies that the large scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power-law with an index of $\alpha=0.82\pm0.03$, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkH$\alpha$ 101) in the region. The magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques are potential of explaining such a decreasing trend., Comment: 25 pages, 19 figures, Accepted for publication in The Astrophysical Journal

Published
2020

21. The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333

Author

Jason Fiege, Di Li, Fumitaka Nakamura, Patrick M. Koch, J. S. Richer, Matthew Joseph Griffin, Jason M. Kirk, Miju Kang, Geumsook Park, Nagayoshi Ohashi, Erica Franzmann, Tetsuo Hasegawa, Tetsuya Zenko, Jia-Wei Wang, Qilao Gu, Brendan Retter, Martin Houde, Per Friberg, Junhao Liu, Tsuyoshi Inoue, Keping Qiu, Sam Falle, Minho Choi, Hao Yuan Duan, Philippe André, Jennifer Hatchell, Kate Pattle, Charles L. H. Hull, Sven Van Loo, Gary A. Fuller, Hsi-Wei Yen, Hyunju Yoo, Ramprasad Rao, Yasuo Doi, Takayoshi Kusune, Hiro Saito, Koji S. Kawabata, Kevin Lacaille, Mark G. Rawlings, Takashi Onaka, Pierre Bastien, Woojin Kwon, Mi Ryang Kim, S. P. S. Eyres, Chin-Fei Lee, Tae-Soo Pyo, Giorgio Savini, Yapeng Zhang, Serena Viti, Ya-Wen Tang, Doug Johnstone, Masumichi Seta, Ray S. Furuya, Francisca Kemper, Huei Ru Vivien Chen, Jihye Hwang, Saeko S. Hayashi, Yong-Hee Lee, S. L. Kim, Zhiwei Chen, Sang-Sung Lee, Shih-Ping Lai, Hongchi Wang, Masato I. N. Kobayashi, Lei Qian, Wen Ping Chen, Sung-ju Kang, Chuan Peng Zhang, Andrew Rigby, Shu-ichiro Inutsuka, Kazunari Iwasaki, Thiem Hoang, C. Darren Dowell, Yoshihiro Kanamori, Kyoung Hee Kim, Eun Jung Chung, Masafumi Matsumura, Mehrnoosh Tahani, Chakali Eswaraiah, Michael Chun Yuan Chen, A. Ran Lyo, Gerald Moriarty-Schieven, Ilse De Looze, Jeong-Eun Lee, James Di Francesco, Yusuke Tsukamoto, Yunhee Choi, Dalei Li, Tao Chung Ching, Hua-bai Li, Jane Greaves, Hong-Li Liu, Archana Soam, Vera Konyves, Do-Young Byun, Anthony Peter Whitworth, Brenda C. Matthews, Ilseung Han, Motohide Tamura, Rachel Friesen, Kee-Tae Kim, Simon Coudé, Derek Ward-Thompson, Pham Ngoc Diep, Jianjun Zhou, Gwanjeong Kim, Hyeseung Lee, Anna M. M. Scaife, J.-F. Robitaille, Jinghua Yuan, Y. Shimajiri, Sheng-Yuan Liu, Kohji Tomisaka, Lei Zhu, Hyeong Sik Yun, Lapo Fanciullo, J. H. Kang, Harriet Parsons, Tie Liu, Jongsoo Kim, Tim Gledhill, Nicolas Peretto, Sarah Graves, Sarah Sadavoy, Steve Mairs, Jungmi Kwon, Tetsuya Nagata, Chang Won Lee, Jungyeon Cho, Hiroyuki Nakanishi, Akimasa Kataoka, Chi Yan Law, Il Gyo Jeong, Antonio Chrysostomou, Doris Arzoumanian, Guoyin Zhang, Hiroko Shinnaga, and David Berry

Subjects
Physics, 010504 meteorology & atmospheric sciences, Plane (geometry), Star formation, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Magnetic field, Protein filament, Interstellar medium, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Local field, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

We present new observations of the active star formation region NGC 1333 in the Perseus molecular cloud complex from the James Clerk Maxwell Telescope B -Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. The BISTRO data cover the entire NGC 1333 complex (∼1.5 pc × 2 pc) at 0.02 pc resolution and spatially resolve the polarized emission from individual filamentary structures for the first time. The inferred magnetic field structure is complex as a whole, with each individual filament aligned at different position angles relative to the local field orientation. We combine the BISTRO data with low- and high- resolution data derived from Planck and interferometers to study the multiscale magnetic field structure in this region. The magnetic field morphology drastically changes below a scale of ∼1 pc and remains continuous from the scales of filaments (∼0.1 pc) to that of protostellar envelopes (∼0.005 pc or ∼1000 au). Finally, we construct simple models in which we assume that the magnetic field is always perpendicular to the long axis of the filaments. We demonstrate that the observed variation of the relative orientation between the filament axes and the magnetic field angles are well reproduced by this model, taking into account the projection effects of the magnetic field and filaments relative to the plane of the sky. These projection effects may explain the apparent complexity of the magnetic field structure observed at the resolution of BISTRO data toward the filament network., Erratum published in volume 899, issue 1, 5 p., April 10 2021. DOI: 10.3847/1538-4357/abf2b3

Published
2020

22. Dust polarized emission observations of NGC 6334; BISTRO reveals the details of the complex but organized magnetic field structure of the high-mass star-forming hub-filament network

Author

Antonio Chrysostomou, Patrick M. Koch, Ya-Wen Tang, David S. Berry, C. D. Dowell, Ling Zhu, Jongsoo Kim, Jia-Wei Wang, Shih-Ping Lai, Zhiwei Chen, Shu-ichiro Inutsuka, Jane Greaves, Vera Konyves, Do-Young Byun, Chang Won Lee, Gary A. Fuller, J. M. C. Rawlings, Takashi Onaka, Charles L. H. Hull, Pierre Bastien, Tsuyoshi Inoue, Jason Fiege, Il-Gyo Jeong, J. Hatchell, Hiroko Shinnaga, Pham Ngoc Diep, I. De Looze, Tyler Bourke, Mark G. Rawlings, Jihye Hwang, Tim Gledhill, Di Li, Fumitaka Nakamura, Brenda C. Matthews, Anna M. M. Scaife, J. Di Francesco, Xing Lu, Harriet Parsons, S. Coude, J.-F. Robitaille, Kohji Tomisaka, Koji S. Kawabata, Sincheol Kang, Rachel Friesen, Chi-Yan Law, Xindi Tang, Jason M. Kirk, Mehrnoosh Tahani, S. Mairs, Serena Viti, Jungmi Kwon, Akimasa Kataoka, Masumichi Seta, Geumsook Park, Nagayoshi Ohashi, Tetsuya Nagata, Erica Franzmann, A-Ran Lyo, Sophia Dai, P. Andre, Mingshui Chen, Saeko S. Hayashi, Woojin Kwon, S. L. Kim, Doris Arzoumanian, Junhao Liu, Hsi-Wei Yen, Hyunju Yoo, Chakali Eswaraiah, Y. Shimajiri, Lei Qian, Minho Choi, Yan Duan, Martin Houde, I. Han, Sang-Sung Lee, Kazunari Iwasaki, Masafumi Matsumura, Lapo Fanciullo, Matthew Joseph Griffin, Miju Kang, Tao-Chung Ching, Jeong-Eun Lee, S. P. S. Eyres, Tetsuo Hasegawa, Sarah Sadavoy, Ray S. Furuya, Qilao Gu, D. Johnstone, Hongchi Wang, Yusuke Tsukamoto, Nicolas Peretto, John Richer, Kee-Tae Kim, Keping Qiu, S. Van Loo, Mi-Ryang Kim, Gwanjeong Kim, Gerald Moriarty-Schieven, Motohide Tamura, G. Zhang, A. P. Whitworth, N. B. Ngoc, Sam Falle, Sarah Graves, Hiro Saito, Kyoung Hee Kim, Jinghua Yuan, Wen Ping Chen, Eun Jung Chung, Dalei Li, Sheng-Yuan Liu, L. M. Fissel, Jungyeon Cho, Tetsuya Zenko, Archana Soam, Hiroyuki Nakanishi, Giorgio Savini, Brendan Retter, Takayoshi Kusune, Chin-Fei Lee, Yasuo Doi, Kate Pattle, Kevin Lacaille, Hyeong-Sik Yun, J. H. Kang, Hyeseung Lee, Tae-Soo Pyo, Tie Liu, Francisca Kemper, Yong-Hee Lee, Thiem Hoang, Le Ngoc Tram, Chuan Peng Zhang, Derek Ward-Thompson, Jianjun Zhou, Florian Kirchschlager, Per Friberg, Ramprasad Rao, Jinjin Xie, Hua-bai Li, David Eden, Huei Ru Vivien Chen, Masato I. N. Kobayashi, Yapeng Zhang, Andrew Rigby, Hao-Yuan Duan, Hong-Li Liu, and Y. K. Choi

Subjects
010504 meteorology & atmospheric sciences, ISM: structure, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, ISM: clouds, Spectral line, Protein filament, 0103 physical sciences, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, polarization, stars: formation, Star formation, Astronomy and Astrophysics, Ridge (differential geometry), Polarization (waves), Astrophysics - Astrophysics of Galaxies, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), submillimeter: ISM, ISM: magnetic fields
Abstract

[Abridged] Filaments and hubs have received special attention recently thanks to studies showing their role in star formation. While the column density and velocity structures of both filaments and hubs have been studied, their magnetic fields (B-field) are not yet characterized. We aim to understand the role of the B-field in the dynamical evolution of the NGC 6334 hub-filament network. We present new observations of the dust polarized emission at 850$\mu$m towards NGC 6334 obtained with the JCMT/POL-2. We study the distribution and dispersion of the polarized intensity ($PI$), the polarization fraction ($PF$), and the B-field angle ($\theta_{B}$). We derive the power spectrum of the intensity and $\theta_{B}$ along the ridge crest. Our analyses show a complex B-field structure when observed over the whole region ($\sim10$ pc), however, at smaller scales ($\sim1$ pc), $\theta_{B}$ varies coherently along the filaments. The observed power spectrum of $\theta_{B}$ can be well represented with a power law function with a slope $-1.33\pm0.23$, which is $\sim20\%$ shallower than that of $I$. This result is compatible with the properties of simulated filaments and may indicate the processes at play in the formation of filaments. $\theta_{B}$ rotates from being mostly perpendicular to the filament crests to mostly parallel as they merge with the hubs. This variation of $\theta_{B}$ may be tracing local velocity flows of matter in-falling onto the hubs. Our analysis suggests a variation of the energy balance along the crests of these filaments, from magnetically critical/supercritical at their far ends to magnetically subcritical near the hubs. We detect an increase of $PF$ towards the high-column density star cluster-forming hubs that may result from the increase of grain alignment efficiency due to stellar radiation from the newborn stars., Comment: Accepted for publication in Astronomy & Astrophysics

Published
2020
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23. Erratum: 'The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333' (2020, ApJ, 899, 28)

Author

Il Gyo Jeong, Fumitaka Nakamura, Jason M. Kirk, Geumsook Park, Nagayoshi Ohashi, Erica Franzmann, Jongsoo Kim, Doris Arzoumanian, Saeko S. Hayashi, Thiem Hoang, Hongchi Wang, Simon Coudé, Pham Ngoc Diep, Tae-Soo Pyo, Chang Won Lee, Sven Van Loo, Chakali Eswaraiah, Sung-ju Kang, Jihye Hwang, Tao Chung Ching, Per Friberg, Derek Ward-Thompson, Martin Houde, Philippe André, C. Darren Dowell, Francisca Kemper, Sarah Graves, Hsi-Wei Yen, Hyunju Yoo, Hyeseung Lee, Jianjun Zhou, Gerald Moriarty-Schieven, Jason Fiege, Harriet Parsons, Yong-Hee Lee, Jennifer Hatchell, Ramprasad Rao, Yasuo Doi, Y. Shimajiri, Mi Ryang Kim, John Richer, Kee-Tae Kim, Motohide Tamura, Di Li, Chuan Peng Zhang, Woojin Kwon, Mark G. Rawlings, Tim Gledhill, Jia-Wei Wang, Anna M. M. Scaife, J.-F. Robitaille, Kohji Tomisaka, Hong-Li Liu, S. L. Kim, Jungyeon Cho, Masumichi Seta, J. H. Kang, Mehrnoosh Tahani, Tie Liu, A. Ran Lyo, Tetsuya Zenko, Sang-Sung Lee, Shu-ichiro Inutsuka, Lapo Fanciullo, Hao Yuan Duan, Hua-bai Li, Tsuyoshi Inoue, Hiroyuki Nakanishi, Nicolas Peretto, Akimasa Kataoka, Patrick M. Koch, Doug Johnstone, Ya-Wen Tang, Eun Jung Chung, Shih-Ping Lai, Masato I. N. Kobayashi, Takayoshi Kusune, Chin-Fei Lee, Steve Mairs, Jungmi Kwon, Tetsuya Nagata, Giorgio Savini, Ray S. Furuya, James Di Francesco, Brenda C. Matthews, Dalei Li, Lei Qian, Zhiwei Chen, Michael Chun-Yuan Chen, Ilseung Han, Kate Pattle, Jane Greaves, Miju Kang, Kazunari Iwasaki, Archana Soam, Anthony Peter Whitworth, Kyoung Hee Kim, Charles L. H. Hull, Chi Yan Law, Koji S. Kawabata, Kevin Lacaille, Vera Konyves, Do-Young Byun, Yoshihiro Kanamori, Huei Ru Vivien Chen, Qilao Gu, Masafumi Matsumura, Hyeong Sik Yun, Sheng-Yuan Liu, Lei Zhu, Yunhee Choi, Ilse De Looze, Jeong-Eun Lee, Yusuke Tsukamoto, Yapeng Zhang, Andrew Rigby, Brendan Retter, Sarah Sadavoy, Gwanjeong Kim, Antonio Chrysostomou, Junhao Liu, Minho Choi, Gary A. Fuller, Guoyin Zhang, Takashi Onaka, Pierre Bastien, Hiroko Shinnaga, S. P. S. Eyres, David Berry, Rachel Friesen, Matthew Joseph Griffin, Tetsuo Hasegawa, Sam Falle, Serena Viti, Hiro Saito, Jinghua Yuan, Wen Ping Chen, and Keping Qiu

Subjects
Physics, Brewster's angle, Magnetic structure, Field (physics), F510, Molecular cloud, Astronomy and Astrophysics, Astrophysics, Position angle, Magnetic field, symbols.namesake, Space and Planetary Science, Magnitude (astronomy), symbols, Planck
Abstract

In the published article, we presented high-resolution polarimetry data obtained by using JCMT SCUBA-2/POL-2, and compared them with the larger-scale magnetic structure observed by Planck (Planck Collaboration et al. 2020). There was a miscalculation in the analysis of the Planck data for comparison, and the mean position angle of the Planck magnetic field should be corrected from -40° ± 7° to -48° ± 6°. Thus, we replace the descriptions in the published article as follows. In Section 4.2, paragraph 3, the second sentence should read: "The differences between the orientations of IRAS 4A, IRAS 4B, and IRAS 2A are not statistically significant, but they do show significantly different orientations from those of the global B-field observed by Planck (-48° ± 6°; Section 4.1)." In Section 4.1, paragraph 3, the second line should read: "The Planck B-field orientation shows a smoothly and slowly varying field distribution with a position angle of -48° ± 6° in our observed NGC 1333 area." Accordingly, we replace Figures 4, 5, 9, 10, and 17 to reflect the correct Planck data. As described above, this error of modest magnitude is related only to our derivation of the Planck polarization angle, and the JCMT observation results are unaffected. Therefore, all conclusions drawn in the published article are unchanged even after the above correction is applied. The 1 pc scale magnetic field observed by Planck shows a smooth distribution, and the interstellar magnetic field in molecular clouds increases the complexity significantly on the scale of less than 1 pc.

Published
2021
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24. Filament Rotation in the California L1482 Cloud

Author

Rodrigo H. Álvarez-Gutiérrez, Ralf S. Klessen, Rodrigo Reeves, Amelia M. Stutz, Chi Yan Law, Hong-Li Liu, Nathan W. C. Leigh, and Stefan Reissl

Subjects
Physics, Angular momentum, 010504 meteorology & atmospheric sciences, Mass distribution, Star formation, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Breakup, Rotation, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Protein filament, Gravitational potential, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

We analyze the gas mass distribution, the gas kinematics, and the young stellar object (YSO) content of the California Molecular Cloud (CMC) L1482 filament. We derive a Gaia DR2 YSO distance of 511$^{+17}_{-16}$ pc. We derive scale-free power-laws for the mean gas line-mass (M/L) profiles; we calculate the gravitational potential and field profiles consistent with these. We present IRAM 30 m C$^{18}$O (1-0) (and other tracers) position-velocity (PV) diagrams that exhibit complex velocity twisting and turning structures. We find a rotational profile in C$^{18}$O perpendicular to the southern filament ridgeline. The profile is regular, confined ($r\lesssim0.4$ pc), anti-symmetric, and to first order linear with a break at $r\sim0.25$ pc. The timescales of the inner (outer) gradients are $\sim$0.7 (6.0) Myr. We show that the centripetal force, compared to gravity, increases toward the break; when the ratio of forces approaches unity, the profile turns over, just before filament breakup is achieved. The timescales and relative roles of gravity to rotation indicate that the structure is stable, long lived ($\sim$ a few times 6 Myr), and undergoing outside-in evolution. Moreover, this filament has practically no star formation, a perpendicular Planck plane-of-the-sky (POS) magnetic field morphology, and POS "zig-zag" morphology, which together with the rotation profile lead to the suggestion that the 3D shape is a corkscrew filament with a helical magnetic field. These results, combined with results in Orion and G035.39-00.33, suggest evolution toward higher densities as rotating filaments shed angular momentum. Thus, magnetic fields may be an essential feature of high-mass (M $\sim10^5$ M$_{\odot}$) cloud filament evolution toward cluster formation., Comment: 23 pages, 17 figures. Accepted for publication in the Astrophysical Journal

Published
2021
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25. An Alert System for Informing Environmental Risk of Dengue Infections

Author

Chi Yan Law, Hui Lin, Shui Shan Lee, Man Kwan Lee, and Ngai Sze Wong

Subjects
Infection risk, Geographic information system, Geospatial analysis, business.industry, Incidence (epidemiology), medicine.disease, Ovitrap, computer.software_genre, Dengue fever, Geography, Environmental risk, Environmental health, medicine, business, computer, Alert system
Abstract

Dengue is a mosquito-borne infection the incidence of which varies with the environment and climate. Knowingly, the reported incidence of dengue is an insensitive indicator of infection risk in a locality. The Ovitrap Index has been in use in many countries. This index is a measurement of mosquito eggs in specified geographic locations which, in turn, reflects the distribution of Aedine mosquitoes, the vector for dengue. An alert system, founded on the Geographic Information System (GIS) technology, was created from a synthesis of geospatial data on ovitrap indices in Hong Kong. The inter-relationship between ovitrap indices and temperature was studied. This inference forms the rationale for the generation of weighted overlays to define risk levels. The weighting can be adjusted to set the sensitivity of the alert system. The system is operational at two levels: (1) for the general public to assist in the evaluation of dengue risk in the community, and (2) for professionals and academia in undertaking technical analysis. The alert system offers one objective means to defining the risk of dengue in a society, which would not be affected by the incidence of the infection itself.

Published
2007
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26. An Alert System for Informing Environmental Risk of Dengue Infections.

Author

Cartwright, William, Gartner, Georg, Liqiu Meng, Peterson, Michael P., Lai, Poh C., Mak, Ann S. H., Wong, Ngai Sze, Chi Yan Law, Man Kwan Lee, Shui Shan Lee, and Hui Lin

Abstract

Dengue is a mosquito-borne infection the incidence of which varies with the environment and climate. Knowingly, the reported incidence of dengue is an insensitive indicator of infection risk in a locality. The Ovitrap Index has been in use in many countries. This index is a measurement of mosquito eggs in specified geographic locations which, in turn, reflects the distribution of Aedine mosquitoes, the vector for dengue. An alert system, founded on the Geographic Information System (GIS) technology, was created from a synthesis of geospatial data on ovitrap indices in Hong Kong. The inter-relationship between ovitrap indices and temperature was studied. This inference forms the rationale for the generation of weighted overlays to define risk levels. The weighting can be adjusted to set the sensitivity of the alert system. The system is operational at two levels: (1) for the general public to assist in the evaluation of dengue risk in the community, and (2) for professionals and academia in undertaking technical analysis. The alert system offers one objective means to defining the risk of dengue in a society, which would not be affected by the incidence of the infection itself. [ABSTRACT FROM AUTHOR]

Published
2007
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27. Applying the Velocity Gradient Technique in NGC 1333: Comparison with Dust Polarization Observations

Author

Archana Soam, Ka Ho Yuen, Ian Stephens, Chi Yan Law, Ka Wai Ho, and Simon Coudé

Subjects
Interstellar medium, Diffuse nebulae, Interstellar magnetic fields, Astrophysics, QB460-466
Abstract

Magnetic fields ( B -fields) are ubiquitous in the interstellar medium (ISM), and they play an essential role in the formation of molecular clouds and subsequent star formation. However, B -fields in interstellar environments remain challenging to measure, and their properties typically need to be inferred from dust polarization observations over multiple physical scales. In this work, we seek to use a recently proposed approach called the velocity gradient technique (VGT) to study B -fields in star-forming regions and compare the results with dust polarization observations in different wavelengths. The VGT is based on the anisotropic properties of eddies in magnetized turbulence to derive B -field properties in the ISM. We investigate that this technique is synergistic with dust polarimetry when applied to a turbulent diffused medium for the purpose of measuring its magnetization. Specifically, we use the VGT on molecular line data toward the NGC 1333 star-forming region ( ^12 CO, ^13 CO, C ^18 O, and N _2 H ^+ ), and we compare the derived B -field properties with those inferred from 214 and 850 μ m dust polarization observations of the region using Stratospheric Observatory for Infrared Astronomy/High-Resolution Airborne Wide-band Camera Plus and James Clerk Maxwell Telescope/POL-2, respectively. We estimate both the inclination angle and the 3D Alfvénic Mach number M _A from the molecular line gradients. Crucially, testing this technique on gravitationally bound, dynamic, and turbulent regions, and comparing the results with those obtained from polarization observations at different wavelengths, such as the plane-of-sky field orientation, is an important test on the applicability of the VGT in various density regimes of the ISM. We in general do not find a close correlation between the velocity gradient inferred orientations and the dust inferred magnetic field orientations.

Published
2024
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