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48 results on '"Hua-bai Li"'

1. 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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2. Turbulence in Zeeman Measurements from Molecular Clouds

Author

Zhuo Cao and Hua-bai Li

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

Magnetic fields (B-fields) play an important role in molecular cloud fragmentation and star formation, but are very difficult to detect. The temporal correlation between the field strength (B) and gas density (n) of an isolated cloud has been suggested as an indication of the dynamical importance of B-fields relative to self-gravity. This temporal B-n relation is, however, unobservable. What can be observed using Zeeman measurements are the "spatial B-n relations" from the current plane of the sky. Nevertheless, the temporal B-n relation argument has still been widely used to interpret observations. Here we present the first numerical test of the legitimacy of this interpretation. From a simulation that can reproduce the observed Zeeman spatial B~n^2/3 relation, we found that temporal B-n relations of individual cores bear no resemblance to the spatial B-n relations. This result inspired us to discover that the true mechanism behind the 2/3 index is random turbulence compression instead of symmetrical gravitational contraction., accepted by ApJL

Published
2023
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3. 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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4. 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

5. 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

6. 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

7. Magnetic Fields in Molecular Clouds—Observation and Interpretation

Author

Hua-bai Li

Subjects
Physics, Zeeman effect, 010308 nuclear & particles physics, Ambipolar diffusion, Star formation, Turbulence, Molecular cloud, Astronomy, turbulence, Astronomy and Astrophysics, magnetic field, QB1-991, Astrophysics, 01 natural sciences, star formation, Magnetic field, Gravitation, symbols.namesake, 0103 physical sciences, symbols, Anisotropy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The Zeeman effect and dust grain alignment are two major methods for probing magnetic fields (B-fields) in molecular clouds, largely motivated by the study of star formation, as the B-field may regulate gravitational contraction and channel turbulence velocity. This review summarizes our observations of B-fields over the past decade, along with our interpretation. Galactic B-fields anchor molecular clouds down to cloud cores with scales around 0.1 pc and densities of 104–5 H2/cc. Within the cores, turbulence can be slightly super-Alfvénic, while the bulk volumes of parental clouds are sub-Alfvénic. The consequences of these largely ordered cloud B-fields on fragmentation and star formation are observed. The above paradigm is very different from the generally accepted theory during the first decade of the century, when cloud turbulence was assumed to be highly super-Alfvénic. Thus, turbulence anisotropy and turbulence-induced ambipolar diffusion are also revisited.

Published
2021

8. 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
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9. 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

10. 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

11. Velocity Anisotropy in Self-gravitating Molecular Clouds. II. Observation

Author

Shun-Sun Luk, Hua-bai Li, and Di Li

Subjects
Space and Planetary Science, Astronomy and Astrophysics
Abstract

The view on velocity structures in molecular clouds and their relationship with magnetic fields (B field) has evolved during the past decade from almost no correlation to highly parallel. Our numerical simulations suggest a more nuanced picture: Depending on whether the self-gravity is dynamically dominant, the velocity field can be governed by either contraction (at high densities) or turbulence (at low densities), and their anisotropies will tend to be either perpendicular or parallel, respectively, to the B fields. High-density regions are always embedded in the low-density fore/background, so the velocity behaviors from lines of sight (LOSs) with high column densities will be a mixture of orthogonal anisotropies, which can be hard to interpret and necessitates zooming in onto certain LOS scales to better characterize localized behaviors. We tested and confirmed the above prediction with CO observations of the Taurus molecular cloud.

Published
2022
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12. Magnetic Fields in Massive Star-forming Regions (MagMaR). II. Tomography through Dust and Molecular Line Polarization in NGC 6334I(N)

Author

Paulo C. Cortés, Patricio Sanhueza, Martin Houde, Sergio Martín, Charles L. H. Hull, Josep M. Girart, Qizhou Zhang, Manuel Fernandez-Lopez, Luis A. Zapata, Ian W. Stephens, Hua-bai Li, Benjamin Wu, Fernando Olguin, Xing Lu, Andres E. Guzmán, and Fumitaka Nakamura

Subjects
Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Here, we report ALMA detections of polarized emission from dust, CS($J=5 \rightarrow 4$), and C$^{33}$S($J=5 \rightarrow 4$) toward the high-mass star-forming region NGC6334I(N). A clear ``hourglass'' magnetic field morphology was inferred from the polarized dust emission which is also directly seen from the polarized CS emission across velocity, where the polarization appears to be parallel to the field. By considering previous findings, the field retains a pinched shape which can be traced to clump length-scales from the envelope scales traced by ALMA, suggesting that the field is dynamically important across multiple length-scales in this region. The CS total intensity emission is found to be optically thick ($��_{\mathrm{CS}} = 32 \pm 12$) while the C$^{33}$S emission appears to be optically thin ($��_{\mathrm{C^{33}S}} = 0.1 \pm 0.01$). This suggests that sources of anisotropy other than large velocity gradients, i.e. anisotropies in the radiation field are required to explain the polarized emission from CS seen by ALMA. By using four variants of the Davis-Chandrasekhar-Fermi technique and the angle dispersion function methods (ADF), we obtain an average of estimates for the magnetic field strength onto the plane of the sky of $\left< \mathrm{B}_{\mathrm{pos}} \right> = 16$ mG from the dust and $\left< \mathrm{B}_{\mathrm{pos}} \right> \sim 2$ mG from the CS emission, where each emission traces different molecular hydrogen number densities. This effectively enables a tomographic view of the magnetic field within a single ALMA observation., Accepted for publication in ApJ

Published
2021
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13. 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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14. SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution – Survey Description and Compact Source Catalogue

Author

Karine Demyk, Mark G. Rawlings, Giuseppe Cosentino, Lixia Yuan, Gwanjeong Kim, Dimitris Stamatellos, Satoshi Ohashi, Dalei Li, Yasuo Doi, L. Harvey-Smith, Archana Soam, Anthony Peter Whitworth, Mark Thompson, Izaskun Jiménez-Serra, Gary A. Fuller, Huei-Ru Chen, Tae-Geun Ji, Oscar Morata, Chakali Eswaraiah, Jinyi Yang, Takeshi Sakai, Y. L. Yuan, Hiroko Shinnaga, David Cornu, Jonathan Rawlings, Walter Kieran Gear, Shaila Akhter, Yuri Aikawa, A. Chrysostomou, Fanyi Meng, Andrew Walsh, Christine D. Wilson, P. M. McGehee, M. Chen, Tomoya Hirota, Carsten Henkel, You-Hua Chu, E. Falgarone, S. Kim, Yuxin He, Johanna Malinen, Sung-ju Kang, Chin-Fei Lee, Xuepeng Chen, Miju Kang, Annie Hughes, V.-M. Pelkonen, Graham S. Bell, Woojin Kwon, Huawei Zhang, Bon-Chul Koo, E. Jarken, Glenn J. White, J. X. Ge, Andrew Rigby, A-Ran Lyo, Wayne S. Holland, Hong-Li Liu, Geumsook Park, Mengyao Tang, Emily Drabek-Maunder, Hee-Weon Yi, M. Liu, Tie Liu, Rebeka Bögner, J.-P. Bernard, C. P. Zhang, B. S. Wang, Manash R. Samal, Harriet Parsons, Mika Juvela, Toby J. T. Moore, Lei Zhu, Ya-Wen Tang, Guobao Zhang, Leonardo Bronfman, George J. Bendo, S. Mairs, Serena Viti, H. Wang, Tetsuo Hasegawa, Yuxin Lin, Minho Choi, Zhiyuan Ren, Ke Wang, Yi-Jehng Kuan, David Eden, I. Ristorcelli, Lei Qian, X. Chen, Paul F. Goldsmith, Jinhua He, Diego Mardones, Shih-Ping Lai, Di Li, Soojong Pak, Qizhou Zhang, Ken'ichi Tatematsu, L. Montier, Yuefang Wu, C. Zhou, Guido Garay, Patricio Sanhueza, A. Rivera-Ingraham, Nicolas Peretto, Keping Qiu, Siyi Feng, Patrick M. Koch, Neal J. Evans, Jeong-Eun Lee, Andrew Blain, A. P. Marston, Hua-bai Li, M. Fich, Chao Zhang, Eun Jung Chung, G. Luo, J. Montillaud, Derek Ward-Thompson, Jianjun Zhou, Maria Cunningham, Jungha Kim, N. Lo, Roberta Paladini, J. Di Francesco, Jongsoo Kim, Ye Xu, Xing Lu, Charlotte Vastel, Chang Won Lee, Pak Shing Li, John A. P. Lopez, Per Friberg, Sheng-Li Qin, Gerald Moriarty-Schieven, D. Alina, G. Pech, Wen Ping Chen, O. Fehér, Pei Zuo, Sheng-Yuan Liu, Jinghua Yuan, Scott Chapman, Alessio Traficante, Doug Johnstone, Jane Greaves, Do-Young Byun, Naomi Hirano, Helen J. Fraser, Jiali Wang, Koji S. Kawabata, J. G. A. Wouterloot, X. Guan, Hsien Shang, Annie Zavagno, John Richer, Kee-Tae Kim, Sarolta Zahorecz, Kate Pattle, Y. Lee, L. V. Toth, Kevin Lacaille, Department of Physics, Particle Physics and Astrophysics, Liverpool John Moores University (LJMU), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Arizona, 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 national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Milky Way, Continuum (design consultancy), SPIRAL ARMS, FOS: Physical sciences, F800, Astrophysics, 01 natural sciences, ISM: clouds, Luminosity, STAR-FORMATION, CLUMP IDENTIFICATION, symbols.namesake, surveys, 0103 physical sciences, Planck, GOULD BELT SURVEY, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Solar and Stellar Astrophysics (astro-ph.SR), QC, QB, Physics, LEGACY SURVEY, Spiral galaxy, stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ATLASGAL, Astronomy and Astrophysics, Galactic plane, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, CLOUD, submillimetre: ISM, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], GAS, Astrophysics of Galaxies (astro-ph.GA), symbols, MILKY-WAY, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], COMPLETE SAMPLE
Abstract

We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850-um continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These data are at an angular resolution of 14.4 arcsec, significantly improving upon the 353-GHz resolution of Planck at 5 arcmin, and allowing for a catalogue of 3528 compact sources in 558 PGCCs. We find that the detected PGCCs have significant sub-structure, with 61 per cent of detected PGCCs having 3 or more compact sources, with filamentary structure also prevalent within the sample. A detection rate of 45 per cent is found across the survey, which is 95 per cent complete to Planck column densities of $N_{H_{2}}$ $>$ 5 $\times$ 10$^{21}$ cm$^{-2}$. By positionally associating the SCOPE compact sources with YSOs, the star formation efficiency, as measured by the ratio of luminosity to mass, in nearby clouds is found to be similar to that in the more distant Galactic Plane, with the column density distributions also indistinguishable from each other., 16 pages, 13 figures, 1 table. Accepted for publication in MNRAS

Published
2019
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15. JCMT BISTRO Survey: Magnetic Fields within the Hub-filament Structure in IC 5146

Author

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

Subjects
individual objects (IC 5146) [ISM], 010504 meteorology & atmospheric sciences, FOS: Physical sciences, ISM [radio continuum], Probability density function, Astrophysics, 01 natural sciences, law.invention, Protein filament, ISM: individual objects (IC 5146), ISM: magnetic fields, ISM: structure, polarization, radio continuum: ISM, stars: formation, law, 0103 physical sciences, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, formation [stars], Turbulence, F510, Bolometer, magnetic fields [ISM], Astronomy and Astrophysics, Polarimeter, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), structure [ISM]
Abstract

We present the 850 $\mu$m polarization observations toward the IC5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope (JCMT), as part of the B-fields In STar forming Regions Observations (BISTRO). This work is aimed at revealing the magnetic field morphology within a core-scale ($\lesssim 1.0$ pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether or not the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function (PDF) of the observed polarization fraction for low signal-to-noise ratio (SNR) data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in $A_V\sim$ 20--300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5$\pm$0.2 mG toward the central hub using the Davis-Chandrasekhar-Fermi method, corresponding to a mass-to-flux criticality of $\sim$ $1.3\pm0.4$ and an Alfv\'{e}nic Mach number of $, Comment: 24 pages, 15 figures, accepted for publication in ApJ

Published
2019
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16. 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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17. Anchoring Magnetic Fields in Turbulent Molecular Clouds II - from 0.1 to 0.01 parsec

Author

H. H. Wang, Y. Zhang, Z. Guo, and Hua-bai Li

Subjects
Physics, Space and Planetary Science, Turbulence, Molecular cloud, Astrophysics of Galaxies (astro-ph.GA), Physics::Space Physics, Anchoring, FOS: Physical sciences, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, Computational physics
Abstract

We (Li et al. 2009; Paper-I) compared the magnetic field directions inferred from polarimetry data obtained from 100-pc scale inter-cloud media (ICM) and from sub-pc scale molecular cloud cores. The highly correlated result led us to conclude that cloud turbulence must be sub-Alfvenic. Here we extend the study with 0.01-pc cores observed by interferometers. The inferred field directions at this scale significantly deviate from that of the surrounding ICM. An obvious question to ask is whether this high-resolution result contradicts the sub-Alfvenic picture concluded earlier. We performed MHD simulations of a slightly super-critical (magnetic criticality = 2) clouds with Alfvenic Mach number $M_A = 0.63$, which can reproduce the Paper-I results, and observed the development towards smaller scales. Interestingly, all subregions hosting cores with $n_H$$_2$ > $10^{5}$/cc (the typical density observed by interferometers) possess $M_A = 2-3$. Not too surprisingly, these slightly super-Alfvenic cores result in B-field orientation offsets comparable to the interferometer observations. The result suggests that gravity can concentrate (and maybe also contribute to, which takes more study to confirm) turbulent energy and create slightly super-Alfvenic cores out from sub-Alfvenic clouds. The results of our simulations also agree with the observed velocity-scale (Kauffmann et al. 2013), mass-scale (Lombardi et al. 2010) and field strength-density (Li et al. 2015; Crutcher et al. 2010) relations., accepted by ApJ, 2019

Published
2019
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18. The link between magnetic fields and filamentary clouds II: Bimodal linear mass distributions

Author

Po Kin Leung, C. Y. Law, and Hua-bai Li

Subjects
Physics, 010308 nuclear & particles physics, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Magnetic field, Computational physics, Astrophysics - Solar and Stellar Astrophysics, Fragmentation (mass spectrometry), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Perpendicular, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

By comparing cumulative linear mass profiles of 12 Gould Belt molecular clouds within 500 pc, we study how the linear mass distributions of molecular clouds vary with the angles between the molecular cloud long axes and the directions of the local magnetic fields (cloud-field direction offsets). We find that molecular clouds with the long axes perpendicular to the magnetic field directions show more even distributions of the linear mass. The result supports that magnetic field orientations can affect the fragmentation of molecular clouds (Li et al. 2017)., Comment: We presented an overestimated SRC values in the published version. The corrected values are presented in this version.An erratum is also submitted

Published
2019
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19. A Holistic Perspective on the Dynamics of G035.39-00.33 : The Interplay between Gas and Magnetic Fields

Author

Mark G. Rawlings, Shih-Ping Lai, Sung-ju Kang, Huei-Ru Chen, Huawei Zhang, Geumsook Park, Kate Pattle, L. Montier, Yuefang Wu, Isabelle Ristorcelli, L. V. Toth, Ke Wang, Qilao Gu, Glenn J. White, Naomi Hirano, D. Alina, Mengyao Tang, Chakali Eswaraiah, Patricio Sanhueza, Ken'ichi Tatematsu, Harriet Parsons, Sheng-Li Qin, Sheng-Yuan Liu, Paul F. Goldsmith, Qizhou Zhang, Michel Fich, Edith Falgarone, David Eden, Hee-Weon Yi, Woojin Kwon, Jinghua Yuan, Jongsoo Kim, Gwanjeong Kim, J. G. A. Wouterloot, Archana Soam, Mark Thompson, Chuan-Peng Zhang, Mika Juvela, Evert Nasedkin, Jia-Wei Wang, Patrick M. Koch, Hua-bai Li, Kee-Tae Kim, Keping Qiu, Gary A. Fuller, Pak Shing Li, James Di Francesco, Jane Greaves, Di Li, Neal J. Evans, Ya-Wen Tang, Johanna Malinen, Vlas Sokolov, Tie Liu, Derek Ward-Thompson, Zhiyuan Ren, Chang Won Lee, and Department of Physics

Subjects
FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: clouds, Protein filament, CLUMP IDENTIFICATION, INFRARED DARK CLOUD, 0103 physical sciences, Gravitational collapse, COLD CLUMPS, Infrared dark cloud, DUST EMISSION, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, Physics, F990, stars: formation, 010308 nuclear & particles physics, Star formation, ZEEMAN OBSERVATIONS, Molecular cloud, IRDC G035.39-00.33, Astronomy and Astrophysics, Polarization (waves), 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), SIMULATIONS, Magnetic field, FILAMENTARY MOLECULAR CLOUDS, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ISM: magnetic fields, FRAGMENTATION, MASSIVE STARS
Abstract

Magnetic field is one of the key agents that play a crucial role in shaping molecular clouds and regulating star formation, yet the complete information on the magnetic field is not well constrained due to the limitations in observations. We study the magnetic field in the massive infrared dark cloud G035.39-00.33 from dust continuum polarization observations at 850 $\micron$ with SCUBA-2/POL-2 at JCMT. The magnetic field tends to be perpendicular to the densest part of the main filament (F$_{M}$), whereas it has a less defined relative orientation in the rest of the structure, where it tends to be parallel to some diffuse regions. A mean plane-of-the-sky magnetic field strength of $\sim$50 $\mu$G for F$_{M}$ is obtained using Davis-Chandrasekhar-Fermi method. Based on $^{13}$CO (1-0) line observations, we suggest a formation scenario of F$_{M}$ due to large-scale ($\sim$10 pc) cloud-cloud collision. Using additional NH$_3$ line data, we estimate that F$_{M}$ will be gravitationally unstable if it is only supported by thermal pressure and turbulence. The northern part of F$_{M}$, however, can be stabilized by a modest additional support from the local magnetic field. The middle and southern parts of F$_{M}$ are likely unstable even if the magnetic field support is taken into account. We claim that the clumps in F$_{M}$ may be supported by turbulence and magnetic fields against gravitational collapse. Finally, we identified for the first time a massive ($\sim$200 M$_{\sun}$), collapsing starless clump candidate, "c8", in G035.39-00.33. The magnetic field surrounding "c8" is likely pinched, hinting at an accretion flow along the filament., Comment: Published on ApJ, 27 pages

Published
2018
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20. A First Look at BISTRO Observations of The $\rho$ Oph-A core

Author

Jungmi Kwon, Yasuo Doi, Motohide Tamura, Masafumi Matsumura, Kate Pattle, David Berry, Sarah Sadavoy, Brenda C. Matthews, Derek Ward-Thompson, Tetsuo Hasegawa, Ray S. Furuya, Andy Pon, James Di Francesco, Doris Arzoumanian, Saeko S. Hayashi, Koji S. Kawabata, Takashi Onaka, Minho Choi, Miju Kang, Thiem Hoang, Chang Won Lee, Sang-Sung Lee, Hong-Li Liu, Tie Liu, Shu-ichiro Inutsuka, Chakali Eswaraiah, Pierre Bastien, Woojin Kwon, Shih-Ping Lai, Keping Qiu, Simon Coudé, Erica Franzmann, Per Friberg, Sarah F. Graves, Jane S. Greaves, Martin Houde, Doug Johnstone, Jason M. Kirk, Patrick M. Koch, Di Li, Harriet Parsons, Ramprasad Rao, Mark G. Rawlings, Hiroko Shinnaga, Sven van Loo, Yusuke Aso, Do-Young Byun, Huei-Ru Chen, Mike C.-Y. Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Antonio Chrysostomou, Eun Jung Chung, Emily Drabek-Maunder, Stewart P. S. Eyres, Jason Fiege, Rachel K. Friesen, Gary Fuller, Tim Gledhill, Matt J. Griffin, Qilao Gu, Jennifer Hatchell, Wayne Holland, Tsuyoshi Inoue, Kazunari Iwasaki, Il-Gyo Jeong, Ji-hyun Kang, Sung-ju Kang, Francisca Kemper, Gwanjeong Kim, Jongsoo Kim, Kee-Tae Kim, Kyoung Hee Kim, Mi-Ryang Kim, Shinyoung Kim, Kevin M. Lacaille, Jeong-Eun Lee, Dalei Li, Hua-bai Li, Junhao Liu, Sheng-Yuan Liu, A-Ran Lyo, Steve Mairs, Gerald H. Moriarty-Schieven, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Brendan Retter, John Richer, Andrew Rigby, Jean-Franois Robitaille, Giorgio Savini, Anna M. M. Scaife, Archana Soam, Ya-Wen Tang, Kohji Tomisaka, Hongchi Wang, Jia-Wei Wang, Anthony P. Whitworth, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Chuan-Peng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Philippe André, C. Darren Dowell, Sam Falle, Yusuke Tsukamoto, Takao Nakagawa, Yoshihiro Kanamori, Akimasa Kataoka, Masato I. N. Kobayashi, Tetsuya Nagata, Hiro Saito, Masumichi Seta, and Tetsuya Zenko

Subjects
010504 meteorology & atmospheric sciences, ISM: structure, media_common.quotation_subject, Polarimetry, ISM [radio continuum], Astrophysics, individual objects (Ophiuchi) [ISM], Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, circumstellar matter, law.invention, ISM: individual objects (Ophiuchi), law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, F990, polarization, formation [stars], Bolometer, Polarimeter, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, radio, Wavelength, Sky, Space and Planetary Science, Degree of polarization, structure [ISM]
Abstract

著者人数: 122名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 權, 靜美; 中西, 裕之; 中川, 貴雄）, Accepted: 2018-03-26, 資料番号: SA1170332000

Published
2018
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21. Magnetic fields towards Ophiuchus-b derived from scuba-2 polarization measurements

Author

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

Subjects
Field line, ISM: structure, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, QB, Physics, polarization, stars: formation, 010308 nuclear & particles physics, Star formation, ISM: individual objects (Ophiuchus), Molecular cloud, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, radio continuum: ISM, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ophiuchus, Degree of polarization, Astrophysics::Earth and Planetary Astrophysics
Abstract

著者人数: 124名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 權, 靜美), Accepted: 2018-05-10, 資料番号: SA1180101000

Published
2018
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22. Erratum: The link between magnetic field orientations and star formation rates

Author

Qilao Gu, Xiaodan Fan, Hangjin Jiang, Hua-bai Li, and Yapeng Zhang

Subjects
Physics, Star formation, Astronomy, Astronomy and Astrophysics, Link (knot theory), Background image, Magnetic field
Abstract

Nature Astronomy 1, 0158 (2017); published 19 June 2017; corrected 17 July 2017. In the version of this Letter originally published the Fig. 1 background image credit was incorrect and should have read: ESO/S. Guisard (www.eso.org/∼sguisard). This has been corrected in all versions of the Letter.

Published
2017
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23. Physical properties of the star-forming clusters in NGC 6334

Author

Peter Schilke, Álvaro Sánchez-Monge, Qizhou Zhang, Josep M. Girart, Carmen Juárez, Hua-bai Li, K. S. Tang, Daniel Seifried, Hauyu Baobab Liu, S. D. Clarke, A. Aghababaei, and M. Sadaghiani

Subjects
Physics, 010308 nuclear & particles physics, Space and Planetary Science, 0103 physical sciences, Continuum (design consultancy), Astronomy and Astrophysics, Astrophysics, Star (graph theory), 010303 astronomy & astrophysics, 01 natural sciences, Dust emission
Abstract

Aims. We aim to characterise certain physical properties of high-mass star-forming sites in the NGC 6334 molecular cloud, such as the core mass function (CMF), spatial distribution of cores, and mass segregation. Methods. We used the Atacama Large Millimeter/sub-millimeter Array (ALMA) to image the embedded clusters NGC 6334-I and NGC 6334-I(N) in the continuum emission at 87.6 GHz. We achieved a spatial resolution of 1300 au, enough to resolve different compact cores and fragments, and to study the properties of the clusters. Results. We detected 142 compact sources distributed over the whole surveyed area. The ALMA compact sources are clustered in different regions. We used different machine-learning algorithms to identify four main clusters: NGC 6334-I, NGC 6334-I(N), NGC 6334-I(NW), and NGC 6334-E. The typical separations between cluster members range from 4000 au to 12 000 au. These separations, together with the core masses (0.1–100 M⊙), are in agreement with the fragmentation being controlled by turbulence at scales of 0.1 pc. We find that the CMFs show an apparent excess of high-mass cores compared to the stellar initial mass function. We evaluated the effects of temperature and unresolved multiplicity on the derived slope of the CMF. Based on this, we conclude that the excess of high-mass cores might be spurious and due to inaccurate temperature determinations and/or resolution limitations. We searched for evidence of mass segregation in the clusters and we find that clusters NGC 6334-I and NGC 6334-I(N) show hints of segregation with the most massive cores located in the centre of the clusters. Conclusions. We searched for correlations between the physical properties of the four embedded clusters and their evolutionary stage (based on the presence of H II regions and infrared sources). NGC 6334-E appears as the most evolved cluster, already harbouring a well-developed H II region. NGC 6334-I is the second-most evolved cluster with an ultra-compact H II region. NGC 6334-I(N) contains the largest population of dust cores distributed in two filamentary structures and no dominant H II region. Finally, NGC 6334-I(NW) is a cluster of mainly low-mass dust cores with no clear signs of massive cores or H II regions. We find a larger separation between cluster members in the more evolved clusters favouring the role of gas expulsion and stellar ejection with evolution. The mass segregation, seen in the NGC 6334-I and NGC 6334-I(N) clusters, suggests a primordial origin for NGC 6334-I(N). In contrast, the segregation in NGC 6334-I might be due to dynamical effects. Finally, the lack of massive cores in the most evolved cluster suggests that the gas reservoir is already exhausted, while the less evolved clusters still have a large gas reservoir along with the presence of massive cores. In general, the fragmentation process of NGC 6334 at large scales (from filament to clump, i.e. at about 1 pc) is likely governed by turbulent pressure, while at smaller scales (scale of cores and sub-fragments, i.e. a few hundred au) thermal pressure starts to be more significant.

Published
2020
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24. Bayesian Revisit of the Relationship between the Total Field Strength and the Volume Density of Interstellar Clouds

Author

Hangjin Jiang, Xiaodan Fan, and Hua-bai Li

Subjects
Physics, Space and Planetary Science, Bayesian probability, Interstellar cloud, Astronomy and Astrophysics, Astrophysics, Total field, Volume density
Abstract

The Zeeman effect has been the only method to directly probe the magnetic field strength in molecular clouds. The Bayesian analysis of Zeeman measurements carried out by Crutcher et al. is the only reference for cloud magnetic field strength. Here we extended their model and Bayesian analysis of the relation between field strength (B) and volume density (n) in the following three directions based on the recent observational and theoretical development. First, we take R, the observational uncertainty of n, as a parameter to be estimated from data. Second, the restriction of α, the index of the B–n relationship, is relieved from [0, 0.75] to [0, 1]. Third, we allow f, the minimum-to-maximum B ratio, to vary with n. Our results show that taking R as a parameter provides a better fitting to the B–n relationship and much more reliable estimates on R, f, and the changing point of α. Arguably our most important finding is that α cannot be reliably estimated by any of the models studied here, either from us or Crutcher et al., if R > 2, which is indeed the case from our estimate. This is the so-called errors-in-variables bias, a well known problem for statisticians.

Published
2020
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25. Velocity Anisotropy in Self-Gravitating Molecular Clouds. I: Simulation

Author

Hua-bai Li, Wei-Guang Ji, and Frank Otto

Subjects
Physics, Turbulence, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Critical value, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, 010305 fluids & plasmas, Computational physics, Magnetic field, Interstellar medium, symbols.namesake, Mach number, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Gravitational collapse, symbols, Anisotropy, 010303 astronomy & astrophysics
Abstract

The complex interplay between turbulence, magnetic fields, and self-gravity leads to the formation of molecular clouds out of the diffuse interstellar medium (ISM). One avenue of studying this interplay is by analyzing statistical features derived from observations, where the interpretation of these features is greatly facilitated by comparisons with numerical simulations. Here we focus on the statistical anisotropy present in synthetic maps of velocity centroid data, which we derive from three-dimensional magnetohydrodynamic simulations of a turbulent, magnetized, self-gravitating patch of ISM. We study how the orientation and magnitude of the velocity anisotropy correlate with the magnetic field and with the structures generated by gravitational collapse. Motivated by recent observational constraints, our simulations focus on the supersonic (sonic Mach number $\mathcal{M} \approx 2 - 17$) but sub- to trans-alfvenic (alfvenic Mach number $\mathcal{M}_A \approx 0.2 - 1.2$) turbulence regime, and we consider clouds which are barely to mildly magnetically supercritical (mass-to-flux ratio equal to once or twice the critical value). Additionally we explore the impact of the turbulence driving mechanism (solenoidal or compressive) on the velocity anisotropy. While we confirm previous findings that the velocity anisotropy generally aligns well with the plane-of-sky magnetic field, our inclusion of the effects of self-gravity reveals that in regions of higher column density, the velocity anisotropy may be destroyed or even reoriented to align with the gravitationally formed structures. We provide evidence that this effect is not necessarily due to the increase of $\mathcal{M}_A$ inside the high-density regions., Comment: 18 pages, 15 figures. Accepted for publication in ApJ

Published
2017
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26. The Link between Magnetic-field Orientations and Star Formation Rates

Author

Hua-bai Li, Xiaodan Fan, Hangjin Jiang, Qilao Gu, and Yapeng Zhang

Subjects
Physics, Field (physics), 010308 nuclear & particles physics, Star formation, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Link (geometry), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Magnetic field, Interstellar medium, Stars, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Perpendicular, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Understanding star formation rates (SFR) is a central goal of modern star-formation models, which mainly involve gravity, turbulence and, in some cases, magnetic fields (B-fields). However, a connection between B-fields and SFR has never been observed. Here, a comparison between the surveys of SFR and a study of cloud-field alignment - which revealed a bimodal (parallel or perpendicular) alignment - shows consistently lower SFR per solar mass for clouds almost perpendicular to the B-fields. This is evidence of B-fields being a primary regulator of SFR. The perpendicular alignment possesses a significantly higher magnetic flux than the parallel alignment and thus a stronger support of the gas against self-gravity. This results in overall lower masses of the fragmented components, which are in agreement with the lower SFR., Comment: Nature Astronomy 2017

Published
2017
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27. AMBIPOLAR DIFFUSION AND TURBULENT MAGNETIC FIELDS IN MOLECULAR CLOUDS

Author

Thomas G. Phillips, Talayeh Hezareh, Hua-bai Li, and Martin Houde

Subjects
Physics, Nuclear and High Energy Physics, Field (physics), Ambipolar diffusion, Star formation, Molecular cloud, Interstellar cloud, General Physics and Astronomy, Astronomy and Astrophysics, Plasma, Molecular physics, Magnetic field, Interstellar medium, Atomic physics, Astrophysics::Galaxy Astrophysics
Abstract

We review the introduction and development of a novel method for the characterization of magnetic fields in star-forming regions. The technique is based on the comparison of spectral line profiles from coexistent neutral and ion molecular species commonly detected in molecular clouds, sites of star formation. Unlike other methods used to study magnetic fields in the cold interstellar medium, this ion/neutral technique is not based on spin interactions with the field. Instead, it relies on and takes advantage of the strong cyclotron coupling between the ions and magnetic fields, thus exposing what is probably the clearest observational manifestation of magnetic fields in the cold, weakly ionized gas that characterizes the interior of molecular clouds. We will show how recent development and modeling of the ensuing ion line narrowing effect leads to a determination of the ambipolar diffusion scale involving the turbulent component of magnetic fields in star-forming regions, as well as the strength of the ordered component of the magnetic field.

Published
2011
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29. Evidence for dynamically important magnetic fields in molecular clouds

Author

Jonathan H. Kawamura, Abigail Hedden, Raymond Blundell, Hua-bai Li, Edward Tong, and Scott Paine

Subjects
Physics, Space and Planetary Science, Star formation, Turbulence, Molecular cloud, Astronomy and Astrophysics, Field strength, Mass ratio, Magnetohydrodynamics, Anisotropy, Computational physics, Magnetic field
Abstract

Recent observational evidence that magnetic fields are dynamically important in molecular clouds, compared to self-gravity and turbulence, is reviewed and illustrated with data from the NGC 2024 region. One piece of evidence, turbulence anisotropy, was found in the diffuse envelope of a cloud (A v ≈ 1; Heyer et al. 2008); our data further suggest turbulence anisotropy in the cloud (A v > 7) and even near the cloud core (A v ∼ 100). The data also show that magnetic fields can channel gravitational contraction even for a region with supercritical N(H 2 )/2B los ratio (the ratio between the observed column density and two times the line-of-sight observed field strength), a parameter which has been widely used by observers to estimate core mass-to-flux ratios. Although the mass-to-flux ratio is constant under the flux-freezing condition, we show that N(H 2 )/2B los grows with time if gravitational contraction is anisotropic due to magnetic fields.

Published
2010
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30. THE DECREASE OF SPECIFIC ANGULAR MOMENTUM AND THE HOT TOROID FORMATION: THE MASSIVE CLUMP G10.6–0.4

Author

Paul T. P. Ho, Eric Keto, Hua-bai Li, Hauyu Baobab Liu, Jingwen Wu, and Qizhou Zhang

Subjects
Physics, Toroid, Accretion (meteorology), FOS: Physical sciences, Astronomy and Astrophysics, Angular velocity, Astrophysics, Radius, Type (model theory), Specific relative angular momentum, Spectral line, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

This is the first paper of our series of high resolution (1") studies of the massive star forming region G10.6--0.4. We present the emission line observations of the hot core type tracers (O$^{13}$CS, OCS, SO$_{2}$) with $\sim$0$"$.5 resolution. By comparing the results to the high--resolution NH$_{3}$ absorption line observation, we confirm for the first time the rotationally flattened hot toroid in the central $, Comment: 26 pages, 5 figures, Accepted by ApJ

Published
2010
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31. Probing the Turbulence Dissipation Range and Magnetic Field Strengths in Molecular Clouds. II. Directly Probing the Ion–neutral Decoupling Scale

Author

Hua-bai Li, Wing-Kit Lee, and Kwok Sun Tang

Subjects
Physics, 010308 nuclear & particles physics, Turbulence, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Decoupling (cosmology), Dissipation, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Spectral line, Magnetic field, Ion, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ionization, 0103 physical sciences, Atomic physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The linewidth of ions has been observed to be systematically narrower than that of the coexisting neutrals in molecular clouds (Houde et al. 2000) and been interpreted as the signature of the decoupling of the neutral turbulence from magnetic fields in partially ionized medium (Li & Houde 2008; Paper I, hereafter). As a sequel of Paper I, here we present further observational evidence that lend support to these earlier proposals with the velocity coordinate spectrum analysis (Lazarian & Pogosyan 2006). We recover the turbulent energy spectra of HCN and HCO+(4-3) in a starless molecular filament in NGC 6334 where magnetic fields play a dynamically important role (Li et al. 2015). Our analysis showed that the neutral spectrum is consistent with Kolmogorov-type (k^-5/3, where k is the wave number), while that of the ions is the same on the large scale but steeper (k^-2) for scales smaller than 0.404pc. We carefully ruled out the possibilities that the spectrum difference can stem from the differences of ion and neutral optical depth and hyper-fine structures.

Published
2018
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32. TRACING TURBULENT AMBIPOLAR DIFFUSION IN MOLECULAR CLOUDS

Author

Shih-Ping Lai, Martin Houde, Tirupati K. Sridharan, and Hua-bai Li

Subjects
Physics, Molecular diffusion, Turbulent diffusion, 010308 nuclear & particles physics, Star formation, Ambipolar diffusion, Turbulence, FOS: Physical sciences, Velocity dispersion, Astronomy and Astrophysics, 01 natural sciences, Physics - Plasma Physics, Magnetic field, Computational physics, Plasma Physics (physics.plasm-ph), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Diffusion (business), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Though flux freezing is a good approximation frequently assumed for molecular clouds, ambipolar diffusion (AD) is inevitable at certain scales. The scale at which AD sets in can be a crucial parameter for turbulence and the star formation process. However, both observation and simulation of AD are very challenging and our knowledge of it is very limited. We proposed earlier (Li and Houde 2008) that the difference between ion and neutral velocity spectra is a signature of turbulent AD and can be used to estimate the AD scales and magnetic field strength. Here we present observational evidence showing that this difference between the velocity dispersions from coexistent ions and neutrals is indeed correlated with magnetic field strength., Comment: accepted by ApJ

Published
2010
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33. POLARIMETRY OF DG TAU AT 350 μm

Author

Tristan G. Matthews, M. Krejny, H. Shinnaga, Jungyeon Cho, Giles Novak, Hua-bai Li, and John E. Vaillancourt

Subjects
Physics, Opacity, Polarimetry, Astronomy and Astrophysics, Polarimeter, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Polarization (waves), Spectral line, Caltech Submillimeter Observatory, symbols.namesake, T Tauri star, Space and Planetary Science, symbols, Astrophysics::Solar and Stellar Astrophysics, Stokes parameters, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present the first 350 micron polarization measurement for the disk of the T Tauri star (TTS) DG Tau. The data were obtained using the SHARP polarimeter at the Caltech Submillimeter Observatory. We did not detect polarization but we provide constraints on the normalized Stokes parameters q and u. We derive information about the polarization spectrum by comparing our 350 micron result with an 850 micron polarization detection previously published for this source. This empirical information concerning the polarization spectrum disagrees with the predictions of a recent model for TTS disk polarization. We conclude, however, that adding more mass to the model disk would probably result in model polarization spectra that agree much better with the 350 and 850 micron polarimetric observations. We suggest that multiwavelength polarimetry of TTS disk emission may provide a promising method for probing the opacity of TTS disks.

Published
2009
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34. DISPERSION OF OBSERVED POSITION ANGLES OF SUBMILLIMETER POLARIZATION IN MOLECULAR CLOUDS

Author

Jessie L. Dotson, Giles Novak, and Hua-bai Li

Subjects
Physics, Magnetic energy, Molecular cloud, Astrophysics (astro-ph), Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Field strength, Polarimeter, Astrophysics, Polarization (waves), Magnetic field, Space and Planetary Science, Turbulence kinetic energy
Abstract

One can estimate the characteristic magnetic field strength in GMCs by comparing submillimeter polarimetric observations of these sources with simulated polarization maps developed using a range of different values for the assumed field strength. The point of comparison is the degree of order in the distribution of polarization position angles. In a recent paper by H. Li and collaborators, such a comparison was carried out using SPARO observations of two GMCs, and employing simulations by E. Ostriker and collaborators. Here we reexamine this same question, using the same data set and the same simulations, but using an approach that differs in several respects. The most important difference is that we incorporate new, higher angular resolution observations for one of the clouds, obtained using the Hertz polarimeter. We conclude that the agreement between observations and simulations is best when the total magnetic energy (including both uniform and fluctuating field components) is at least as large as the turbulent kinetic energy., revised, accepted version; to appear in The Astrophysical Journal; 20 pages, 2 figures, 2 tables

Published
2009
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35. Local Magnetic Field Role in Star Formation

Author

Zhi-Yun Li, Huei-Ru Chen, Keping Qiu, Ramprasad Rao, Hsi-Wei Yen, Hauyu Baobab Liu, Tao-Chung Ching, Hua-bai Li, Shih-Ping Lai, Josep M. Girart, Marco Padovani, Qizhou Zhang, Patrick M. Koch, Paul T. P. Ho, P. Frau, How-Huan Chen, Ya-Wen Tang, ITA, USA, FRA, ESP, TWN, and HKG

Subjects
Physics, 010504 meteorology & atmospheric sciences, Continuum (measurement), Star formation, General Engineering, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Magnetic field, 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 highlight distinct and systematic observational features of magnetic field morphologies in polarized submm dust continuum. We illustrate this with specific examples and show statistical trends from a sample of 50 star-forming regions., Comment: 4 pages, 3 figures; to appear in the EAS Proceedings of the 6th Zermatt ISM Symposium "Conditions and Impact of Star Formation from Lab to Space", September 2015

Published
2015
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36. Author Correction: The link between magnetic field orientations and star formation rates

Author

Hangjin Jiang, Xiaodan Fan, Qilao Gu, Hua-bai Li, and Yapeng Zhang

Subjects
Physics, Star formation, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Data_FILES, ComputingMilieux_COMPUTERSANDEDUCATION, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Astronomy and Astrophysics, Geometry, Link (knot theory), Table (information), GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Magnetic field
Abstract

In the Supplementary Information file originally published, Supplementary Table 1 was mistakenly omitted. This has now been corrected.

Published
2017
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37. The Importance of the Magnetic Field from an SMA-CSO-Combined Sample of Star-Forming Regions

Author

Hsi-Wei Yen, Zhi-Yun Li, Hauyu Baobab Liu, Huei-Ru Vivien Chen, Keping Qiu, Tao-Chung Ching, Ramprasad Rao, Hua-bai Li, Ya-Wen Tang, Paul T. P. Ho, Patrick M. Koch, Marco Padovani, Qizhou Zhang, How-Huan Chen, P. Frau, Shih-Ping Lai, and Josep M. Girart

Subjects
Physics, Mathematics::Functional Analysis, Star formation, High Energy Physics::Lattice, High Energy Physics::Phenomenology, FOS: Physical sciences, Astronomy and Astrophysics, Field strength, Polarization (waves), Molecular physics, Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Magnetic field, Nonlinear Sciences::Chaotic Dynamics, Caltech Submillimeter Observatory, Mathematics::Group Theory, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Magnetohydrodynamics, Cosmic dust
Abstract

Submillimeter dust polarization measurements of a sample of 50 star-forming regions, observed with the SMA and the CSO covering pc-scale clouds to mpc-scale cores, are analyzed in order to quantify the magnetic field importance. The magnetic field misalignment $\delta$ -- the local angle between magnetic field and dust emission gradient -- is found to be a prime observable, revealing distinct distributions for sources where the magnetic field is preferentially aligned with or perpendicular to the source minor axis. Source-averaged misalignment angles $\langle|\delta|\rangle$ fall into systematically different ranges, reflecting the different source-magnetic field configurations. Possible bimodal $\langle|\delta|\rangle$-distributions are found for the separate SMA and CSO samples. Combining both samples broadens the distribution with a wide maximum peak at small $\langle|\delta|\rangle$-values. Assuming the 50 sources to be representative, the prevailing source-magnetic field configuration is one that statistically prefers small magnetic field misalignments $|\delta|$. When interpreting $|\delta|$ together with an MHD force equation, as developed in the framework of the polarization-intensity gradient method, a sample-based scaling fits the magnetic field tension-to-gravity force ratio $\langle\Sigma_B\rangle$ versus $\langle|\delta|\rangle$ with $\langle\Sigma_B\rangle = 0.116 \cdot \exp(0.047\cdot \langle|\delta|\rangle)\pm 0.20$ (mean error), providing a way to estimate the relative importance of the magnetic field, only based on measurable field misalignments $|\delta|$. The force ratio $\Sigma_B$ discriminates systems that are collapsible on average ($\langle \Sigma_B\rangle 1$) (abridged)., Comment: 43 pages, 11 figures, 2 tables; accepted for publication in ApJ

Published
2014

38. Hot Core, Outflows, and Magnetic Fields in W43-MM1 (G30.79 FIR 10)

Author

Thushara Pillai, Ramprasad Rao, Hua-bai Li, T. K. Sridharan, Nimesh A. Patel, Keping Qiu, Qizhou Zhang, and Paulo C. Cortes

Subjects
Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Polarization (waves), Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Spectral line, Magnetic field, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, Outflow, Astrophysics::Galaxy Astrophysics
Abstract

We present submillimeter spectral line and dust continuum polarization observations of a remarkable hot core and multiple outflows in the high-mass star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter Array (SMA). A temperature of $\sim$ 400 K is estimated for the hot-core using CH$_3$CN (J=19-18) lines, with detections of 11 K-ladder components. The high temperature and the mass estimates for the outflows indicate high-mass star-formation. The continuum polarization pattern shows an ordered distribution, and its orientation over the main outflow appears aligned to the outflow. The derived magnetic field indicates slightly super-critical conditions. While the magnetic and outflow energies are comparable, the B-field orientation appears to have changed from parsec scales to $\sim$ 0.1 pc scales during the core/star-formation process., accepted, ApJ Letters

Published
2014

39. Magnetic Fields and Massive Star Formation

Author

Timea Csengeri, Zhi-Yun Li, Eric Keto, Ya-Wen Tang, How-Huan Chen, Josep M. Girart, Carmen Juárez, Ramprasad Rao, Paul T. P. Ho, Hua-bai Li, Patrick M. Koch, Marco Padovani, Hauyu Baobab Liu, Tao-Chung Ching, Sylvain Bontemps, Shih-Ping Lai, Keping Qiu, Qizhou Zhang, P. Frau, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), École normale supérieure - Paris (ENS-PSL), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Star formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Polarization (waves), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Magnetic field, Stars, Star cluster, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

Massive stars ($M > 8$ \msun) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 $��$m obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of $\lsim$ 0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within $40^\circ$ of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks ($\lsim 10^3$ AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scale of 0.01 - 0.1 pc in the context of massive star and cluster star formation., Accepted for publication in Astrophysical Journal

Published
2014
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40. The Link between Magnetic Fields and Filamentary Clouds: Bimodal Cloud Orientations in the Gould Belt

Author

Thomas Henning, Hua-bai Li, Min Fang, and Jouni Kainulainen

Subjects
Physics, Turbulence, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Magnetic field, Gravitation, Mean field theory, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Physics::Space Physics, Perpendicular, Magnetic cloud, Intercloud, Astrophysics::Galaxy Astrophysics
Abstract

The orientations of filamentary molecular clouds in the Gould Belt and their local ICM (inter-cloud media) magnetic fields are studied using near-infrared dust extinction maps and optical stellar polarimetry data. These filamentary clouds are a few-to-ten parsecs in length, and we find that their orientations tend to be either parallel or perpendicular to the mean field directions of the local ICM. This bimodal distribution is not found in cloud simulations with super-Alfvenic turbulence, in which the cloud orientations should be random. ICM magnetic fields that are dynamically important compared to inertial-range turbulence and self-gravity can readily explain both field-filament configurations. Previous studies commonly recognize that strong magnetic fields can guide gravitational contraction and result in filaments perpendicular to them, but few discuss the fact that magnetic fields can also channel sub-Alfvenic turbulence to form filaments aligned with them. This strong-field scenario of cloud formation is also consistent with the constant field strength observed from ICM to clouds (Crutcher et al. 2010) and is possible to explain the "hub-filament" cloud structure (Myers 2009) and the density threshold of cloud gravitational contraction (Kainulainen et al. 2009)., Comment: 26 pages, 7 figures, accepted by MNRAS

Published
2013
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41. Protostellar Outflow Heating in a Growing Massive Protocluster

Author

Qizhou Zhang, Hua-bai Li, Ke Wang, Huawei Zhang, and Yuefang Wu

Subjects
Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), law.invention, Stars, Star cluster, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), Protostar, Outflow, Infrared dark cloud, Maser, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The dense molecular clump P1 in the infrared dark cloud (IRDC) complex G28.34+0.06 harbors a massive protostellar cluster at its extreme youth. Our previous Submillimeter Array (SMA) observations revealed several jet-like CO outflows emanating from the protostars, indicative of intense accretion and potential interaction with ambient natal materials. Here we present the Expanded Very Large Array (EVLA) spectral line observations toward P1 in the NH3 (J,K) = (1,1), (2,2), (3,3) lines, as well as H2O and class I CH3OH masers. Multiple NH3 transitions reveal the heated gas widely spread in the 1 pc clump. The temperature distribution is highly structured; the heated gas is offset from the protostars, and morphologically matches the outflows very well. Hot spots of spatially compact, spectrally broad NH3 (3,3) emission are also found coincident with the outflows. A weak NH3 (3,3) maser is discovered at the interface between an outflow jet and the ambient gas. These findings suggest that protostellar heating may not be effective in suppressing fragmentation during the formation of massive cores., 15 pages, 4 figures, 1 table, accepted to ApJ Letters

Published
2011

42. Observational Determination of the Turbulent Ambipolar Diffusion Scale and Magnetic Field Strength in Molecular Clouds

Author

Hua-bai Li, C. McCoey, Talayeh Hezareh, and Martin Houde

Subjects
Length scale, Physics, 010308 nuclear & particles physics, Turbulence, Ambipolar diffusion, Molecular cloud, Velocity dispersion, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Dissipation, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Ion, Computational physics, Magnetic field, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We study the correlation of the velocity dispersion of the coexisting molecules H13CN and H13CO+ and the turbulent energy dissipation scale in the DR21(OH) star-forming region. The down-shift of the H13CO+ spectrum relative to H13CN is consistent with the presence of ambipolar diffusion at dissipation length scales that helps the process of turbulent energy dissipation, but at a different cut-off for ions compared to the neutrals. We use our observational data to calculate a turbulent ambipolar diffusion length scale L'\simeq17 mpc and a strength of B_{pos}\simeq1.7 mG for the plane of the sky component of the magnetic field in DR21(OH).

Published
2010
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43. Anchoring Magnetic Field in Turbulent Molecular Clouds

Author

Alyssa A. Goodman, C. Darren Dowell, Hua-bai Li, Giles Novak, and Roger H. Hildebrand

Subjects
Physics, Range (particle radiation), Field (physics), Turbulence, Star formation, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Computational physics, Magnetic field, Orders of magnitude (time), Space and Planetary Science, Cascade, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Galaxy Astrophysics
Abstract

One of the key problems in star formation research is to determine the role of magnetic fields. Starting from the atomic inter-cloud medium (ICM) which has density nH ~ 1 per cubic cm, gas must accumulate from a volume several hundred pc across in order to form a typical molecular cloud. Star formation usually occurs in cloud cores, which have linear sizes below 1 pc and densities nH2 > 10^5 per cubic cm. With current technologies, it is hard to probe magnetic fields at scales lying between the accumulation length and the size of cloud cores, a range corresponds to many levels of turbulent eddy cascade, and many orders of magnitude of density amplification. For field directions detected from the two extremes, however, we show here that a significant correlation is found. Comparing this result with molecular cloud simulations, only the sub-Alfvenic cases result in field orientations consistent with our observations., accepted by ApJ

Published
2009
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44. Magnetic Fields and Infall Motions in NGC 1333 IRAS 4

Author

Jacqueline A. Davidson, John E. Vaillancourt, M. Attard, Giles Novak, Martin Houde, C. Darren Dowell, Hua-bai Li, and Hiroko Shinnaga

Subjects
Physics, 010504 meteorology & atmospheric sciences, Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Continuum flux, 01 natural sciences, Spectral line, Magnetic field, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Gravitational collapse, Uniform field, Emission spectrum, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract

We present single-dish 350 micron dust continuum polarimetry as well as HCN and HCO+ J=4-3 rotational emission spectra obtained on NGC 1333 IRAS 4. The polarimetry indicates a uniform field morphology over a 20" radius from the peak continuum flux of IRAS 4A, in agreement with models of magnetically supported cloud collapse. The field morphology around IRAS 4B appears to be quite distinct however, with indications of depolarization observed towards the peak flux of this source. Inverse P-Cygni profiles are observed in the HCN J=4-3 line spectra towards IRAS 4A, providing a clear indication of infall gas motions. Taken together, the evidence gathered here appears to support the scenario that IRAS 4A is a cloud core in a critical state of support against gravitational collapse., Comment: 23 pages, 6 figures, 2 tables

Published
2009
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45. New results on the submillimeter polarization spectrum of the Orion Molecular Cloud

Author

L. Kirby, M. Attard, H. Shinnaga, Giles Novak, C. D. Dowell, Hua-bai Li, Roger H. Hildebrand, M. Krejny, John E. Vaillancourt, and Martin Houde

Subjects
Physics, Nebula, 010504 meteorology & atmospheric sciences, Molecular cloud, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Polarimeter, Astrophysics, Polarization (waves), 01 natural sciences, Wavelength, Caltech Submillimeter Observatory, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We have used the SHARP polarimeter at the Caltech Submillimeter Observatory to map the polarization at wavelengths of 350 and 450 micron in a ~2 x 3 arcmin region of the Orion Molecular Cloud. The map covers the brightest region of the OMC-1 ridge including the Kleinmann-Low (KL) nebula and the submillimeter source Orion-south. The ratio of 450-to-350 micron polarization is ~ 1.3 +/- 0.3 in the outer parts of the cloud and drops by a factor of 2 towards KL. The outer cloud ratio is consistent with measurements in other clouds at similar wavelengths and confirms previous measurements placing the minimum of the polarization ratio in dusty molecular clouds at a wavelength ~ 350 micron., 7 pages, 6 figures, submitted to ApJ Lett

Published
2008

46. Probing the Turbulence Dissipation Range and Magnetic Field Strengths in Molecular Clouds

Author

Martin Houde and Hua-bai Li

Subjects
Length scale, Physics, Ambipolar diffusion, Turbulence, Molecular cloud, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Molecular physics, Spectral line, Ion, Magnetic field, Space and Planetary Science, 0103 physical sciences, Dispersion (optics), 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We study the turbulent velocity dispersion spectra of the coexistent HCN and HCO+ molecular species as a function of length scale in the M17 star-forming molecular cloud. We show that the observed downward shift of the ion's spectrum relative to that of the neutral is readily explained by the existence of an ambipolar diffusion range within which ion and neutral turbulent energies dissipate differently. We use these observations to evaluate this decoupling scale and show how to estimate the strength of the plane-of-the-sky component of the embedded magnetic field in a completely novel way., Comment: 15 pages, 3 figures, accepted for publication in The Astrophysical Journal

Published
2008
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47. Results of SPARO 2003: Mapping Magnetic Fields in Giant Molecular Clouds

Author

Giles Novak, P. G. Calisse, R. F. Loewenstein, Megan Krejny, David T. Chuss, M. Newcomb, G. S. Griffin, and Hua-bai Li

Subjects
Physics, Nebula, Magnetic energy, Field (physics), Molecular cloud, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galactic plane, Magnetic field, Space and Planetary Science, Disc, Astrophysics::Galaxy Astrophysics
Abstract

We present results from the Austral Winter 2003 observing campaign of SPARO, a 450 micron polarimeter used with a two-meter telescope at South Pole. We mapped large-scale magnetic fields in four Giant Molecular Clouds (GMCs) in the Galactic disk: NGC 6334, the Carina Nebula, G333.6-0.2 and G331.5-0.1. We find a statistically significant correlation of the inferred field directions with the orientation of the Galactic plane. Specifically, three of the four GMCs (NGC 6334 is the exception) have mean field directions that are within 15 degrees of the plane. The simplest interpretation is that the field direction tends to be preserved during the process of GMC formation. We have also carried out an analysis of published optical polarimetry data. For the closest of the SPARO GMCs, NGC 6334, we can compare the field direction in the cloud as measured by SPARO with the field direction in a larger region surrounding the cloud, as determined from optical polarimetry. For purposes of comparison, we also use optical polarimetry to determine field directions for other regions of similar size and distance. Overall, the results from this optical polarimetry analysis are consistent with our suggestion that field direction tends to be preserved during GMC formation. Finally, we compare the disorder in our magnetic field maps with the disorder seen in magnetic field maps derived from MHD turbulence simulations. We conclude from these comparisons that the magnetic energy density in our clouds is comparable to the turbulent energy density., Comment: Submitted to Astrophys. J. (one color figure)

Published
2006
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48. The TOP-SCOPE Survey of Planck Galactic Cold Clumps: Survey Overview and Results of an Exemplar Source, PGCC G26.53+0.17

Author

Tie Liu, Kee-Tae Kim, Mika Juvela, Ke Wang, Ken’ichi Tatematsu, James Di Francesco, Sheng-Yuan Liu, Yuefang Wu, Mark Thompson, Gary Fuller, David Eden, Di Li, I. Ristorcelli, Sung-ju Kang, Yuxin Lin, D. Johnstone, J. H. He, P. M. Koch, Patricio Sanhueza, Sheng-Li Qin, Q. Zhang, N. Hirano, Paul F. Goldsmith, Neal J. Evans II, Glenn J. White, Minho Choi, Chang Won Lee, L. V. Toth, Steve Mairs, H.-W. Yi, Mengyao Tang, Archana Soam, N. Peretto, Manash R. Samal, Michel Fich, Harriet Parsons, Jinghua Yuan, Chuan-Peng Zhang, Johanna Malinen, George J. Bendo, A. Rivera-Ingraham, Hong-Li Liu, Jan Wouterloot, Pak Shing Li, Lei Qian, Jonathan Rawlings, Mark G. Rawlings, Siyi Feng, Yuri Aikawa, S. Akhter, Dana Alina, Graham Bell, J.-P. Bernard, Andrew Blain, Rebeka Bőgner, L. Bronfman, D.-Y. Byun, Scott Chapman, Huei-Ru Chen, M. Chen, Wen-Ping Chen, X. Chen, Xuepeng Chen, A. Chrysostomou, Giuliana Cosentino, M. R. Cunningham, K. Demyk, Emily Drabek-Maunder, Yasuo Doi, C. Eswaraiah, Edith Falgarone, O. Fehér, Helen Fraser, Per Friberg, G. Garay, J. X. Ge, W. K. Gear, Jane Greaves, X. Guan, Lisa Harvey-Smith, Tetsuo HASEGAWA, J. Hatchell, Yuxin He, C. Henkel, T. Hirota, W. Holland, A. Hughes, E. Jarken, Tae-Geun Ji, Izaskun Jimenez-Serra, Miju Kang, Koji S. Kawabata, Gwanjeong Kim, Jungha Kim, Jongsoo Kim, Shinyoung Kim, B.-C. Koo, Woojin Kwon, Yi-Jehng Kuan, K. M. Lacaille, Shih-Ping Lai, C. F. Lee, J.-E. Lee, Y.-U. Lee, Dalei Li, Hua-bai Li, N. Lo, John A. P. Lopez, Xing Lu, A-Ran Lyo, D. Mardones, A. Marston, P. McGehee, F. Meng, L. Montier, Julien Montillaud, T. Moore, O. Morata, Gerald H. Moriarty-Schieven, S. Ohashi, Soojong Pak, Geumsook Park, R. Paladini, Kate M Pattle, Gerardo Pech, V.-M. Pelkonen, K. Qiu, Zhi-Yuan Ren, John Richer, M. Saito, Takeshi Sakai, H. Shang, Hiroko Shinnaga, Dimitris Stamatellos, Y.-W. Tang, Alessio Traficante, Charlotte Vastel, S. Viti, Andrew Walsh, Bingru Wang, Hongchi Wang, Junzhi Wang, D. Ward-Thompson, Anthony Whitworth, Ye Xu, J. Yang, Yao-Lun Yang, Lixia Yuan, A. Zavagno, Guoyin Zhang, H.-W. Zhang, Chenlin Zhou, Jianjun Zhou, Lei Zhu, Pei Zuo, Chao Zhang, Department of Physics, Shanghai Astronomical Observatory [Shanghai] (SHAO), Chinese Academy of Sciences [Beijing] (CAS), Korea Astronomy and Space Science Institute (KASI), Okayama University, University of Helsinki, University of New South Wales [Sydney] (UNSW), Peking University [Beijing], Department of Mechanical and Aerospace Engineering [Victoria]], Monash University [Clayton], King‘s College London, National Astronomical Observatories [Beijing] (NAOC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, Polar Research Institute of China, Polar Research Institute of China (PRIC)-UAPS, Center for Northeast Asian Studies, Tohoku University [Sendai], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, SLAC National Accelerator Laboratory (SLAC), Stanford University, School of Physics and Astronomy [Cardiff], Cardiff University, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), University of Cologne, Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Department of Earth and Planetary Sciences [Kobe], Kobe University, Department of Zoology, Auburn University (AU), Departamento de Astronomia (DAS), State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering [Nanjing] (HYDRO-LAB), Hohai University, Swinburne University of Technology (Hawthorn campus), Tokyo University of Science [Tokyo], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Institute of Vertebrate Paleontology and Paleoanthropology, SUPA School of Physics and Astronomy [University of St Andrews], University of St Andrews [Scotland]-Scottish Universities Physics Alliance (SUPA), National Astronomical Observatory of Japan (NAOJ), Royal Institute of Technology [Stockholm] (KTH ), Queen Mary University of London (QMUL), National Taiwan Normal University (NTNU), National Tsing Hua University [Hsinchu] (NTHU), Div Life Sci, Lab Proteome Anal & Mol Physiol, Gyeongsang Natl Univ, Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), foreign laboratories (FL), CERN [Genève], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO)-Université de Brest (UBO), Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Department of Anthropology [University of Toronto], University of Toronto, Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire de Mécanique de Lille - FRE 3723 (LML), Université de Lille, Sciences et Technologies-Ecole Centrale de Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Harvard University [Cambridge], Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), NASA-California Institute of Technology (CALTECH), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), 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), Université de Lille, Sciences et Technologies-Centrale Lille-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Harvard University

Subjects
FOS: Physical sciences, Astrophysics, F500, INITIAL CONDITIONS, LINE-PROFILES, 01 natural sciences, ISM: clouds, ISM: abundances, STAR-FORMATION, Protein filament, Gravitation, symbols.namesake, INFRARED DARK CLOUD, surveys, 0103 physical sciences, DENSE GAS, Infrared dark cloud, Planck, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, QC, QB, Physics, abundances [ISM], ISM: kinematics and dynamics, CLERK MAXWELL TELESCOPE, Spectral index, formation [stars], stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, Molecular cloud, LARGE-SCALE, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, GOULD BELT, FILAMENTARY MOLECULAR CLOUDS, kinematics and dynamics [ISM], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), symbols, Outflow, FRAGMENTATION, clouds [ISM]
Abstract

The low dust temperatures (, Comment: Accepted for publication in the ApJS

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