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1. JCMT BISTRO Observations: Magnetic Field Morphology of Bubbles Associated with NGC 6334

Author

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

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

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

Published
2023
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2. ATOMS : ALMA three-millimeter observations of massive star-forming regions - III. Catalogues of candidate hot molecular cores and hyper/ultra compact H II regions

Author

Juan Li, Ya-Ping Peng, Yong Zhang, Diego Mardones, Sung-ju Kang, X.-W. Liu, Yuefang Wu, Jeong-Eun Lee, Sheng-Yuan Liu, Chang Won Lee, Amelia M. Stutz, Hong-Li Liu, Mengyao Tang, Maria Cunningham, Eswaraiah Chakali, Rodrigo H. Álvarez-Gutiérrez, Mika Juvela, Hee-Weon Yi, Qizhou Zhang, Chao Zhang, Zhi-Qiang Shen, Qiu-Yi Luo, Feng-Wei Xu, Leonardo Bronfman, Guido Garay, Zhiyuan Ren, Shanghuo Li, Neal J. Evans, Rong Liu, Sheng-Li Qin, Jianwen Zhou, Yu Wang, Kee-Tae Kim, Namitha Issac, Tomoya Hirota, Feng-Yao Zhu, Anandmayee Tej, Pak Shing Li, Junzhi Wang, Jingwen Wu, Lokesh K. Dewangan, Ke Wang, L. Viktor Tóth, Tie Liu, Archana Soam, Ken'ichi Tatematsu, Di Li, Qiaowei Xue, Jin-Zeng Li, Paul F. Goldsmith, Hyeong-Sik Yun, T. Baug, Isabelle Ristorcelli, Department of Physics, Institut de recherche en astrophysique et planétologie (IRAP), 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), and 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)

Subjects
stars: kinematics and dynamics, Milky Way, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, Star (graph theory), ISM: clouds, 01 natural sciences, Spectral line, Organic molecules, H II regions, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Physics, stars: formation, 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Millimeter
Abstract

We have identified 453 compact dense cores in 3 mm continuum emission maps in the ATOMS (ALMA Three-millimeter Observations of Massive Star-forming regions) survey, and compiled three catalogues of high-mass star forming cores. One catalogue, referred to as H/UC-HII catalogue, includes 89 cores that enshroud hyper/ultra compact (H/UC) HII regions as characterized by associated compact H40alpha emission. A second catalogue, referred to as pure s-cHMC, includes 32 candidate Hot Molecular Cores (HMCs) showing rich spectra (N>20lines) of complex organic molecules (COMs) but not associated with H/UC-HII regions. The third catalogue, referred to as pure w-cHMC, includes 58 candidate HMCs with relatively low levels of COM richness and not associated with H/UC-HII regions. These three catalogues of dense cores provide an important foundation for future studies of the early stages of high-mass star formation across the Milky Way. We also find that nearly half of H/UC-HII cores are candidate HMCs. From the number counts of COM-containing and H/UC-HII cores, we suggest that the duration of high-mass protostellar cores showing chemically rich features is at least comparable to the lifetime of H/UC-HII regions. For cores in the H/UC-HII catalogue, the width of the H40alpha line increases as the core size decreases, suggesting that the non-thermal dynamical and/or pressure line-broadening mechanisms dominate on the smaller scales of the H/UC-HII cores., 17 pages, five tables, and 11 figures. Accepted for publication at MNRAS

Published
2021
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3. 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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4. Mid-$J$ CO Line Observations of Protostellar Outflows in the Orion Molecular Clouds

Author

S. T. Megeath, Minho Choi, P. Manoj, John H. Bieging, Mi-Ryang Kim, Yunhee Choi, Gwanjeong Kim, Hyunju Yoo, Sung-ju Kang, Geumsook Park, Friedrich Wyrowski, and Miju Kang

Subjects
Physics, 010504 meteorology & atmospheric sciences, Star formation, Molecular cloud, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Kinetic energy, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Luminosity, Cover (topology), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, Outflow, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract

Ten protostellar outflows in the Orion molecular clouds were mapped in the $^{12}$CO/$^{13}$CO ${J=6\rightarrow5}$ and $^{12}$CO ${J=7\rightarrow6}$ lines. The maps of these mid-$J$ CO lines have an angular resolution of about 10$''$ and a typical field size of about 100$''$. Physical parameters of the molecular outflows were derived, including mass transfer rates, kinetic luminosities, and outflow forces. The outflow sample was expanded by re-analyzing archival data of nearby low-luminosity protostars, to cover a wide range of bolometric luminosities. Outflow parameters derived from other transitions of CO were compared. The mid-$J$ ($J_{\rm up} \approx 6$) and low-$J$ ($J_{\rm up} \leq 3$) CO line wings trace essentially the same outflow component. By contrast, the high-$J$ (up to $J_{\rm up} \approx 50$) line-emission luminosity of CO shows little correlation with the kinetic luminosity from the ${J=6\rightarrow5}$ line, which suggests that they trace distinct components. The low/mid-$J$ CO line wings trace long-term outflow behaviors while the high-$J$ CO lines are sensitive to short-term activities. The correlations between the outflow parameters and protostellar properties are presented, which shows that the strengths of molecular outflows increase with bolometric luminosity and envelope mass., Comment: 31 pages, 16 figures, Accepted for publication in ApJS

Published
2021
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5. 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

6. 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

7. ATOMS : ALMA three-millimeter observations of massive star-forming regions - II. Compact objects in ACA observations and star formation scaling relations

Author

Paul F. Goldsmith, Feng-Yao Zhu, Sheng-Yuan Liu, Di Li, Feng-Wei Xu, Pak Shing Li, Jingwen Wu, Mika Juvela, Maria Cunningham, Qiu-Yi Luo, Zhiyuan Ren, Sheng-Li Qin, Qizhou Zhang, Sung-ju Kang, Hyeong-Sik Yun, X.-W. Liu, Yu Wang, Chao Zhang, Diego Mardones, Shanghuo Li, Neal J. Evans, Ken'ichi Tatematsu, Ya-Ping Peng, L. Viktor Tóth, Yuefang Wu, Isabelle Ristorcelli, Hee-Weon Yi, Kee-Tae Kim, Tie Liu, Ke Wang, Jeong-Eun Lee, Anandmayee Tej, Guido Garay, Tomoya Hirota, Chang Won Lee, Leonardo Bronfman, Zhi-Qiang Shen, Junzhi Wang, Namitha Issac, Juan Li, Yong Zhang, Hong-Li Liu, T. Baug, Department of Physics, Institut de recherche en astrophysique et planétologie (IRAP), 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), Shanghai Astronomical Observatory [Shanghai] (SHAO), and Chinese Academy of Sciences [Beijing] (CAS)

Subjects
TRACERS, Milky Way, FOS: Physical sciences, Star (graph theory), 01 natural sciences, ISM: clouds, CLUMPS, clouds -ISM, DENSE MOLECULAR GAS, Observatory, galaxies, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), formation -ISM, Physics, stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, formation, Astronomy, Astronomy and Astrophysics, 115 Astronomy, Space science, Chinese academy of sciences, Astrophysics - Astrophysics of Galaxies, ISM: molecules, HCN, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), galaxies: star formation, MILKY-WAY, Christian ministry, Millimeter, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], molecules -stars
Abstract

We report studies of the relationships between the total bolometric luminosity ($L_{\rm bol}$ or $L_{\rm TIR}$) and the molecular line luminosities of $J=1-0$ transitions of H$^{13}$CN, H$^{13}$CO$^+$, HCN, and HCO$^+$ with data obtained from ACA observations in the "ATOMS" survey of 146 active Galactic star forming regions. The correlations between $L_{\rm bol}$ and molecular line luminosities $L'_{\rm mol}$ of the four transitions all appear to be approximately linear. Line emission of isotopologues shows as large scatters in $L_{\rm bol}$-$L'_{\rm mol}$ relations as their main line emission. The log($L_{\rm bol}$/$L'_{\rm mol}$) for different molecular line tracers have similar distributions. The $L_{\rm bol}$-to-$L'_{\rm mol}$ ratios do not change with galactocentric distances ($R_{\rm GC}$) and clump masses ($M_{\rm clump}$). The molecular line luminosity ratios (HCN-to-HCO$^+$, H$^{13}$CN-to-H$^{13}$CO$^+$, HCN-to-H$^{13}$CN and HCO$^+$-to-H$^{13}$CO$^+$) all appear constant against $L_{\rm bol}$, dust temperature ($T_{\rm d}$), $M_{\rm clump}$ and $R_{\rm GC}$. Our studies suggest that both the main lines and isotopologue lines are good tracers of the total masses of dense gas in Galactic molecular clumps. The large optical depths of main lines do not affect the interpretation of the slopes in star formation relations. We find that the mean star formation efficiency (SFE) of massive Galactic clumps in the "ATOMS" survey is reasonably consistent with other measures of the SFE for dense gas, even those using very different tracers or examining very different spatial scales., Comment: Published on MNRAS. The full tables are included in Tables.pdf or Tables.tex files, which can be downloaded from source files

Published
2020
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8. Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young Stellar Object

Author

Gregory J. Herczeg, Dimitris Stamatellos, Carlos Contreras Peña, Giseon Baek, Jeong-Eun Lee, B. A. Macfarlane, Huei-Ru Vivien Chen, Watson P. Varricatt, Doug Johnstone, Klaus W. Hodapp, and Sung-ju Kang

Subjects
010504 meteorology & atmospheric sciences, Serpens, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, 0103 physical sciences, Radiative transfer, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

In the episodic accretion scenario, a large fraction of the protostellar mass accretes during repeated and large bursts of accretion. Since outbursts on protostars are typically identified at specific wavelengths, interpreting these outbursts requires converting this change in flux to a change in total luminosity. The Class I young stellar object EC 53 in the Serpens Main cloud has undergone repeated increases in brightness at 850 $\mu$m that are likely caused by bursts of accretion. In this study, we perform two- and three-dimensional continuum radiative transfer modeling to quantify the internal luminosity rise in EC 53 that corresponds to the factor of $\sim$1.5 enhancement in flux at 850 $\mu$m. We model the spectral energy distribution and radial intensity profile in both the quiescent and outburst phases. The internal luminosity in the outburst phase is $\sim 3.3$ times brighter than the luminosity in the quiescent phase. The radial intensity profile analysis demonstrates that the detected sub-mm flux variation of EC 53 comes from the heated envelope by the accretion burst. We also find that the role of external heating of the EC 53 envelope by the interstellar radiation field is insignificant., Comment: 16 pages, 14 figures, Accepted for publication in ApJ

Published
2020

9. Multi-scale analysis of the Monoceros OB 1 star-forming region

Author

Douglas J. Marshall, Mika Juvela, Sung-ju Kang, David Cornu, D. Alina, Alessio Traficante, Elisabetta R. Micelotta, Patrick M. Koch, Mark G. Rawlings, Ke Wang, Yasuo Doi, Johanna Malinen, Sarolta Zahorecz, Isabelle Ristorcelli, Jinhua He, Archana Soam, Tie Liu, Rebeka Bögner, Patricio Sanhueza, J. Montillaud, Mika Saajasto, Chang Won Lee, David Eden, L. V. Toth, V. M. Pelkonen, Charlotte Vastel, Kee-Tae Kim, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), 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), University of Helsinki, 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), Liverpool John Moores University (LJMU), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, University of Hawai'i [Hilo], Tokyo University of Science [Tokyo], University of Cologne, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Department of Physics [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, Eötvös Loránd University (ELTE), Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], European Southern Observatory (ESO), This work was supported by the Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES., funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730562[RadioNet], The project leading to this publication has received funding from the 'Soutien à la recherche de l’observatoire' by the OSU THETA., 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), 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), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Department of Physics, and Particle Physics and Astrophysics

Subjects
Infrared, Population, FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, ISM: clouds, law.invention, Telescope, law, 0103 physical sciences, Protostar, education, 010303 astronomy & astrophysics, QC, QB, Physics, education.field_of_study, stars: formation, 010308 nuclear & particles physics, Star formation, extinction, Molecular cloud, Astronomy and Astrophysics, Observable, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), dust, extinction, dust, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. Current theories and models attempt to explain star formation globally, from core scales to giant molecular cloud scales. A multi-scale observational characterisation of an entire molecular complex is necessary to constrain them. We investigate star formation in G202.3+2.5, a ̃10 × 3 pc sub-region of the Monoceros OB1 cloud with a complex morphology that harbours interconnected filamentary structures. Aims: We aim to connect the evolution of cores and filaments in G202.3+2.5 with the global evolution of the cloud and to identify the engines of the cloud dynamics. Methods: In this first paper, the star formation activity is evaluated by surveying the distributions of dense cores and protostars and their evolutionary state, as characterised using both infrared observations from the Herschel and WISE telescopes and molecular line observations with the IRAM 30 m telescope. Results: We find ongoing star formation in the whole cloud, with a local peak in star formation activity around the centre of G202.3+2.5, where a chain of massive cores (10 - 50 M☉) forms a massive ridge (≳150 M☉). All evolutionary stages from starless cores to Class II protostars are found in G202.3+2.5, including a possibly starless and massive (52 M☉) core, which presents a high column density (8 × 1022 cm-2). Conclusions: All the core-scale observables we examined point to an enhanced star formation activity that is centred on the junction between the three main branches of the ramified structure of G202.3+2.5. This suggests that the increased star formation activity results from the convergence of these branches. To further investigate the origin of this enhancement, it is now necessary to extend the analysis to larger scales in order to examine the relationship between cores, filaments, and their environment. We address these points through the analysis of the dynamics of G202.3+2.5 in a joint paper. Context. Current theories and models attempt to explain star formation globally, from core scales to giant molecular cloud scales. A multi-scale observational characterisation of an entire molecular complex is necessary to constrain them. We investigate star formation in G202.3+2.5, a similar to 10 x 3 pc sub-region of the Monoceros OB1 cloud with a complex morphology that harbours interconnected filamentary structures. Aims. We aim to connect the evolution of cores and filaments in G202.3+2.5 with the global evolution of the cloud and to identify the engines of the cloud dynamics. Methods. In this first paper, the star formation activity is evaluated by surveying the distributions of dense cores and protostars and their evolutionary state, as characterised using both infrared observations from the Herschel and WISE telescopes and molecular line observations with the IRAM 30 m telescope. Results. We find ongoing star formation in the whole cloud, with a local peak in star formation activity around the centre of G202.3+2.5, where a chain of massive cores (10 50 M-circle dot) forms a massive ridge (greater than or similar to 150 M-circle dot). All evolutionary stages from starless cores to Class II protostars are found in G202.3+2.5, including a possibly starless and massive (52 M-circle dot) core, which presents a high column density (8 x 10(22) cm(-2)). Conclusions. All the core-scale observables we examined point to an enhanced star formation activity that is centred on the junction between the three main branches of the ramified structure of G202.3+2.5. This suggests that the increased star formation activity results from the convergence of these branches. To further investigate the origin of this enhancement, it is now necessary to extend the analysis to larger scales in order to examine the relationship between cores, filaments, and their environment. We address these points through the analysis of the dynamics of G202.3+2.5 in a joint paper.

Published
2019
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10. 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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11. Multi-scale analysis of the Monoceros OB 1 star-forming region: II. Colliding filaments in the Monoceros OB1 molecular cloud

Author

David Cornu, David Eden, Mika Saajasto, Jinhua He, Charlotte Vastel, Chang Won Lee, D. Alina, Elisabetta R. Micelotta, Kee-Tae Kim, Yasuo Doi, Alessio Traficante, Sarolta Zahorecz, Ke Wang, Sung-ju Kang, Mark G. Rawlings, V. M. Pelkonen, D. J. Marshall, J. Montillaud, Isabelle Ristorcelli, Mika Juvela, Patrick M. Koch, Archana Soam, Johanna Malinen, L. Viktor Tóth, Tie Liu, Rebeka Bögner, Patricio Sanhueza, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), 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), University of Helsinki, 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), Yunnan Observatories, Chinese Academy of Sciences [Changchun Branch] (CAS), UNIV CHILI, Korea Astronomy and Space Science Institute (KASI), Okayama University, Liverpool John Moores University (LJMU), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, University of Hawai'i [Hilo], Tokyo University of Science [Tokyo], University of Cologne, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Department of Physics [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, Eötvös Loránd University (ELTE), European Southern Observatory (ESO), This work was supported by the Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES., funding from the 'Soutien à la recherche de l’observatoire' by the OSU THETA., The project leading to this publication has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730 562 [RadioNet]., 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), 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), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Department of Physics, Particle Physics and Astrophysics, Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and Okayama University [Okayama]

Subjects
Infrared, LINE, FOS: Physical sciences, M QUIET CLUMPS, DUST, Astrophysics, HERBIG-HARO FLOWS, MASS, POLARIMETRY, 01 natural sciences, ISM: clouds, MAGNETIC-FIELDS, Protein filament, 0103 physical sciences, Protostar, 010303 astronomy & astrophysics, QC, QB, Physics, stars: formation, 010308 nuclear & particles physics, Velocity gradient, Star formation, Molecular cloud, Astronomy and Astrophysics, 115 Astronomy, Space science, Collision, Astrophysics - Astrophysics of Galaxies, GAS, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), PROTOCLUSTERS, Vector field, EMISSION, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We started a multi-scale analysis of G202.3+2.5, an intertwined filamentary region of Monoceros OB1. In Paper I, we examined the distributions of dense cores and protostars and found enhanced star formation (SF) activity in the junction region of the filaments. In this second paper, we aim to unveil the connections between the core and filament evolutions, and between the filament dynamics and the global evolution of the cloud. We characterise the gas dynamics and energy balance using Herschel and WISE observations and molecular tracers observed with the IRAM 30m and TRAO 14m telescopes. The velocity field of the cloud is examined and velocity-coherent structures are put in perspective with the cloud environment. Two main velocity components (VCs) are revealed, well separated in the north and merged around the location of intense N2H+ emission where Paper I found the peak of SF activity. The relative position of the two VCs along the sightline, and the velocity gradient in N2H+ emission imply that the VCs have been undergoing collision for ~10^5 yrs. The dense gas where N2H+ is detected is interpreted as the compressed region between the two filaments, which corresponds to a high mass inflow rate of ~1e-3 Msun/yr and possibly leads to an increase in its SF efficiency. We identify a protostar in the junction region that possibly powers two crossed intermittent outflows. We show that the HII region around the nearby cluster NCG 2264 is still expanding and its role in the collision is examined. However, we cannot rule out the idea that the collision arises mostly from the global collapse of the cloud. The (sub-)filament-scale observables examined in this paper reveal a collision between G202.3+2.5 sub-structures and its probable role in feeding the cores in the junction region. One must now characterise the cloud morphology, its fragmentation, and magnetic field, all at high resolution., Comment: A&A, in press; IRAM and TRAO data cubes will be available at CDS

Published
2019
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12. Compressed Magnetic Field in the Magnetically Regulated Global Collapsing Clump of G9.62+0.19

Author

Qizhou Zhang, Mark G. Rawlings, Yuefang Wu, Huei-Ru Chen, Sheng-Yuan Liu, Mika Juvela, Archana Soam, Kee-Tae Kim, Guido Garay, Harriet Parsons, Zhiyuan Ren, Diego Mardones, J. G. A. Wouterloot, Yu-Nung Su, Ken'ichi Tatematsu, Neal J. Evans, Tomoya Hirota, Tie Liu, Sung-ju Kang, Di Li, Paul F. Goldsmith, Pak Shing Li, Sarah Graves, Sheng-Li Qin, Ke Wang, and Department of Physics

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, H-II REGIONS, Ionization, 0103 physical sciences, Gravitational collapse, Astrophysics::Solar and Stellar Astrophysics, SCUBA-2, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, HOT, BORDERS, Star formation, Turbulence, GEOMETRY, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, MASSIVE-STAR-FORMATION, Magnetic field, Interstellar medium, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ISM: magnetic fields
Abstract

How stellar feedback from high-mass stars (e.g., H{\sc ii} regions) influences the surrounding interstellar medium and regulates new star formation is still unclear. To address this question, we observed the G9.62+0.19 complex in 850 $\mu$m continuum with the JCMT/POL-2 polarimeter. An ordered magnetic field has been discovered in its youngest clump, the G9.62 clump. The magnetic field strength is determined to be $\sim$1 mG. Magnetic field plays a larger role than turbulence in supporting the clump. However, the G9.62 clump is still unstable against gravitational collapse even if thermal, turbulent, and magnetic field support are taken into account all together. The magnetic field segments in the outskirts of the G9.62 clump seem to point toward the clump center, resembling a dragged-in morphology, indicating that the clump is likely undergoing magnetically-regulated global collapse. However, The magnetic field in its central region is aligned with the shells of the photodissociation regions (PDRs) and is approximately parallel to the ionization (or shock) front, indicating that the magnetic field therein is likely compressed by the expanding H{\sc ii} regions that formed in the same complex., Comment: 8 pages, 3 figures, accepted to be published on ApJ letter

Published
2018

14. 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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15. 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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16. High-resolution Observations of the Molecular Clouds Associated with the Huge H ii Region CTB 102

Author

Youngsik Kim, Miju Kang, Sung-ju Kang, Brandon Marshall, Charles Kerton, and Minho Choi

Subjects
Physics, H II region, education.field_of_study, Star formation, media_common.quotation_subject, Young stellar object, Molecular cloud, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Radio telescope, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), education, Solar and Stellar Astrophysics (astro-ph.SR), media_common
Abstract

We report the first high-resolution (sub-arcminute) large-scale mapping $^{12}$CO and $^{13}$CO observations of the molecular clouds associated with the giant outer Galaxy HII region CTB~102 (KR 1). These observations were made using a newly commissioned receiver system on the 13.7-m radio telescope at the Taeduk Radio Astronomy Observatory. Our observations show that the molecular clouds have a spatial extent of $60 \times 35$ pc and a total mass of $10^{4.8} - 10^{5.0}$ M$_\odot$. Infrared data from WISE and 2MASS were used to identify and classify the YSO population associated with ongoing star formation activity within the molecular clouds. We directly detect 18 class I/class II YSOs and six transition disk objects. Moving away from the HII region, there is an age/class gradient consistent with sequential star formation. The infrared and molecular-line data were combined to estimate the star formation efficiency (SFE) of the entire cloud as well as the SFE for various sub-regions of the cloud. We find that the overall SFE is between $\sim5 - 10$%, consistent with previous observations of giant molecular clouds. One of the sub-regions, region 1a, is a clear outlier, with a SFE of 17 $-$ 35% on a 5 pc spatial scale. This high SFE is more typical for much smaller (sub-pc scale) star-forming cores, and we think region 1a is likely an embedded massive protocluster., Comment: 16 pages, 8 figures, 5 tables

Published
2019
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17. High-resolution Observations of the Molecular Clouds Associated with the Huge H ii Region CTB 102.

Author

Brandon Marshall, Sung-ju Kang, C. R. Kerton, Youngsik Kim, Minho Choi, and Miju Kang

Subjects
MOLECULAR clouds, RADIO telescopes, STAR formation, RADIO astronomy, ASTRONOMICAL observatories, ASTRONOMICAL surveys
Abstract

We report the first high-resolution (subarcminute) large-scale mapping 12CO and 13CO observations of the molecular clouds associated with the giant outer Galaxy H ii region CTB 102 (KR 1). These observations were made using a newly commissioned receiver system on the 13.7 m radio telescope at the Taeduk Radio Astronomy Observatory. Our observations show that the molecular clouds have a spatial extent of 60 × 35 pc and a total mass of 104.8–105.0M⊙. Infrared data from the Wide-field Infrared Survey Explorer and Two Micron All Sky Survey were used to identify and classify the young stellar object (YSO) population associated with ongoing star formation activity within the molecular clouds. We directly detect 18 class I/class II YSOs and six transition disk objects. Moving away from the H ii region, there is an age/class gradient consistent with sequential star formation. The infrared and molecular-line data were combined to estimate the star formation efficiency (SFE) of the entire cloud as well as the SFE for various subregions of the cloud. We find that the overall SFE is between ∼5% and 10%, consistent with previous observations of giant molecular clouds. One of the subregions, region 1a, is a clear outlier, with a SFE of 17%–35% on a 5 pc spatial scale. This high SFE is more typical for much smaller (subparsec scale) star-forming cores, and we think region 1a is likely an embedded massive protocluster. [ABSTRACT FROM AUTHOR]

Published
2019
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18. Submillimeter continuum variability in planck galactic cold clumps

Author

Kee-Tae Kim, Minho Choi, Chuan Peng Zhang, Miju Kang, Jonathan Rawlings, Steve Mairs, Archana Soam, Tie Liu, Sung-ju Kang, J. Montillaud, David Eden, Hyunju Yoo, Patrick M. Koch, Chang Won Lee, Jeong-Eun Lee, Doug Johnstone, Dimitris Stamatellos, Gary A. Fuller, Patricio Sanhueza, Woojin Kwon, Gwanjeong Kim, Geumsook Park, Mika Juvela, Department of Physics, Korea Astronomy and Space Science Institute (KASI), Okayama University, Department of Plant Biology [Carnegie] (DPB), Carnegie Institution for Science [Washington], University of Helsinki, 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), King‘s College London, Div Life Sci, Lab Proteome Anal & Mol Physiol, and Gyeongsang Natl Univ

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Surveys, general [Submillimeter], 01 natural sciences, symbols.namesake, Accretion rate, surveys, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, SCUBA-2, RATES, Planck, ACCRETION, OUTBURST, COLLAPSE, 010303 astronomy & astrophysics, formation [Stars], James Clerk Maxwell Telescope, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, QC, QB, Physics, stars: formation, Continuum (measurement), STAR, 010308 nuclear & particles physics, Star formation, ATLASGAL, ISM [Submillimeter], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Observable, submillimeter: general, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, EVOLUTION, Wavelength, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), symbols, submillimeter: ISM, COMPLETE SAMPLE, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

In the early stages of star formation, a protostar is deeply embedded in an optically thick envelope such that it is not directly observable. Variations in the protostellar accretion rate, however, will cause luminosity changes that are reprocessed by the surrounding envelope and are observable at submillimeter wavelengths. We searched for submillimeter flux variability toward 12 Planck Galactic Cold Clumps detected by the James Clerk Maxwell Telescope (JCMT)-SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE) survey. These observations were conducted at 850 um using the JCMT/SCUBA-2. Each field was observed three times over about 14 months between 2016 April and 2017 June. We applied a relative flux calibration and achieved a calibration uncertainty of ~ 3.6% on average. We identified 136 clumps across 12 fields and detected four sources with flux variations of ~ 30%. For three of these sources, the variations appear to be primarily due to large-scale contamination, leaving one plausible candidate. The flux change of the candidate may be associated with low- or intermediate-mass star formation assuming a distance of 1.5 kpc, although we cannot completely rule out the possibility that it is a random deviation. Further studies with dedicated monitoring would provide a better understanding of the detailed relationship between submillimeter flux and accretion rate variabilities while enhancing the search for variability in star-forming clumps farther away than the Gould Belt., 14 pages, 7 figures, 3 tables; accepted for publication in ApJS, LaTeX; minor corrections (typos, acronyms, etc.), update of authors' information

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19. Planck Cold Clumps in the lambda Orionis Complex. II. Environmental Effects on Core Formation

Author

Isabelle Ristorcelli, Mark G. Rawlings, Jeong-Eun Lee, P. Sanhueza, Hee-Weon Yi, Chang Won Lee, Hong-Li Liu, James Di Francesco, Tie Liu, Neal J. Evans, L. V. Toth, Mika Juvela, Kee-Tae Kim, David Eden, Glenn J. White, Yao-Lun Yang, Naomi Hirano, Ken'ichi Tatematsu, Sung-ju Kang, Di Li, Mark Thompson, Patrick M. Koch, Ke Wang, Archana Soam, Gary A. Fuller, Hauyu Baobab Liu, Gwanjeong Kim, Minho Choi, Yuefang Wu, Sheng-Yuan Liu, Department of Physics, and Doctoral Programme in Particle Physics and Universe Sciences

Subjects
H II region, Population, Continuum (design consultancy), Astrophysics, ISM: clouds, 114 Physical sciences, 01 natural sciences, STAR-FORMATION, 0103 physical sciences, education, 010303 astronomy & astrophysics, POPULATION, James Clerk Maxwell Telescope, QC, QB, Physics, education.field_of_study, Spectral index, stars: formation, Number density, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, YOUNG STELLAR OBJECTS, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, NEBULA-CLUSTER, EVOLUTION, DARK CLOUDS, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, DISTANCE, MOLECULAR CLOUDS, submillimeter: ISM
Abstract

Based on the 850 $\mu$m dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the $\lambda$ Orionis cloud to those of PGCCs in the Orion A and B clouds. The Orion A and B clouds are well known active star-forming regions, while the $\lambda$ Orionis cloud has a different environment as a consequence of the interaction with a prominent OB association and a giant Hii region. PGCCs in the $\lambda$ Orionis cloud have higher dust temperatures ($Td=16.13\pm0.15$ K) and lower values of dust emissivity spectral index ($ \beta=1.65\pm0.02$) than PGCCs in the Orion A (Td=13.79$\pm 0.21$K, $\beta=2.07\pm0.03$) and Orion B ($Td=13.82\pm0.19$K, $\beta=1.96\pm0.02$) clouds. We find 119 sub-structures within the 40 detected PGCCs and identify them as cores. Of total 119 cores, 15 cores are discovered in the $\lambda$ Orionis cloud, while 74 and 30 cores are found in the Orion A and B clouds, respectively. The cores in the $\lambda$ Orionis cloud show much lower mean values of size R=0.08 pc, column density N(H2)=$(9.5\pm1.2) \times 10^{22}$ cm$^{-2}$, number density n(H2)=$(2.9 \pm 0.4)\times10^{5}$ cm$^{-3}$, and mass $M_{core}$=$1.0\pm0.3$ M$_{\odot}$ compared to the cores in the Orion A (R=0.11pc, $N(H2)=(2.3\pm0.3) \times 10^{23}$ cm$^{-2}$, n(H2)=$(3.8\pm0.5) \times 10^{5}$cm$^{-3}$, and $M_{core}$=$2.4 \pm 0.3$ M$_{\odot}$) and Orion B (R=0.16pc, N(H2)=$(3.8 \pm 0.4) \times 10^{23}$cm$^{-2}$, n(H2)=$(15.6\pm1.8)\times10^{5}$ cm$^{-3}$, and $M_{core}$= $2.7\pm0.3$ M$_{\odot}$) clouds. These core properties in the $\lambda$ Orionis cloud can be attributed to the photodissociation and external heating by the nearby Hii region, which may prevent the PGCCs from forming gravitationally bound structures and eventually disperse them. These results support the idea of negative stellar feedback on core formation.

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

Author

Tie Liu, Pak Shing Li, Mika Juvela, Kee-Tae Kim, Neal J. Evans II, James Di Francesco, Sheng-Yuan Liu, Jinghua Yuan, Ken’ichi Tatematsu, Qizhou Zhang, Derek Ward-Thompson, Gary Fuller, Paul F. Goldsmith, P. M. Koch, Patricio Sanhueza, I. Ristorcelli, Sung-ju Kang, Huei-Ru Chen, N. Hirano, and Yuefang Wu

Subjects
MAGNETIC fields, PLASMA turbulence, STAR formation, MOLECULAR clouds, POLARIZATION (Nuclear physics)
Abstract

Magnetic field plays a crucial role in shaping molecular clouds and regulating star formation, yet the complete information on the magnetic field is not well constrained owing 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 μm with SCUBA-2/POL-2 at JCMT for the first time. The magnetic field tends to be perpendicular to the densest part of the main filament (FM), 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 ∼50 μG for FM is obtained using the Davis–Chandrasekhar–Fermi method. Based on 13CO (1–0) line observations, we suggest a formation scenario of FM due to large-scale (∼10 pc) cloud–cloud collision. Using additional NH3 line data, we estimate that FM will be gravitationally unstable if it is only supported by thermal pressure and turbulence. The northern part of FM, however, can be stabilized by a modest additional support from the local magnetic field. The middle and southern parts of FM are likely unstable even if the magnetic field support is taken into account. We claim that the clumps in FM may be supported by turbulence and magnetic fields against gravitational collapse. Finally, we identified for the first time a massive (∼200 M⊙), 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. [ABSTRACT FROM AUTHOR]

Published
2018
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21. The JCMT Transient Survey: Stochastic and Secular Variability of Protostars and Disks In the Submillimeter Region Observed over 18 Months.

Author

Doug Johnstone, Gregory J. Herczeg, Steve Mairs, Jennifer Hatchell, Geoffrey C. Bower, Helen Kirk, James Lane, Graham S. Bell, Sarah Graves, Yuri Aikawa, Huei-Ru Vivien Chen, Wen-Ping Chen, Miju Kang, Sung-Ju Kang, Jeong-Eun Lee, Oscar Morata, Andy Pon, Peter Scicluna, Aleks Scholz, and Satoko Takahashi

Subjects
PROTOSTARS, DISKS (Astrophysics), STOCHASTIC analysis, STAR formation, STANDARD deviations, RANDOM variables
Abstract

We analyze results from the first 18 months of monthly submillimeter monitoring of eight star-forming regions in the JCMT Transient Survey. In our search for stochastic variability in 1643 bright peaks, only the previously identified source, EC 53, shows behavior well above the expected measurement uncertainty. Another four sources—two disks and two protostars—show moderately enhanced standard deviations in brightness, as expected for stochastic variables. For the two protostars, this apparent variability is the result of single epochs that are much brighter than the mean. In our search for secular brightness variations that are linear in time, we measure the fractional brightness change per year for 150 bright peaks, 50 of which are protostellar. The ensemble distribution of slopes is well fit by a normal distribution with σ ∼ 0.023. Most sources are not rapidly brightening or fading at submillimeter wavelengths. Comparison against time-randomized realizations shows that the width of the distribution is dominated by the uncertainty in the individual brightness measurements of the sources. A toy model for secular variability reveals that an underlying Gaussian distribution of linear fractional brightness change σ = 0.005 would be unobservable in the present sample, whereas an underlying distribution with σ = 0.02 is ruled out. Five protostellar sources, 10% of the protostellar sample, are found to have robust secular measures deviating from a constant flux. The sensitivity to secular brightness variations will improve significantly with a sample over a longer time duration, with an improvement by factor of two expected by the conclusion of our 36 month survey. [ABSTRACT FROM AUTHOR]

Published
2018
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22. 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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23. The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations.

Author

Steve Mairs, Doug Johnstone, Helen Kirk, James Lane, Graham S. Bell, Sarah Graves, Gregory J. Herczeg, Peter Scicluna, Geoffrey C. Bower, Huei-Ru Vivien Chen, Jennifer Hatchell, Yuri Aikawa, Wen-Ping Chen, Miju Kang, Sung-Ju Kang, Jeong-Eun Lee, Oscar Morata, Andy Pon, Aleks Scholz, and Satoko Takahashi

Subjects
STAR formation, PROTOSTARS, STELLAR mass, ACCRETION (Astrophysics), STANDARD deviations
Abstract

Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterized across the observable SED. In this study, we develop methods to robustly analyze repeated observations of an area of the sky for submillimeter variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare 850 μm JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2–4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find seven variable candidates, five of which we classify as Strong, and the remaining two we classify as Extended to indicate that the latter are associated with larger-scale structure. For the Strong variable candidates, we find an average fractional peak brightness change per year of , with a standard deviation of . In total, 7% of the protostars associated with 850 μm emission in our sample show signs of variability. Four of the five Strong sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the 850 μm periodicity of the submillimeter variable source, EC 53, to be 567 ± 32 days, based on the archival Gould Belt Survey data. [ABSTRACT FROM AUTHOR]

Published
2017
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24. The JCMT Transient Survey: Detection of Submillimeter Variability in a Class I Protostar EC 53 in Serpens Main.

Author

Hyunju Yoo, Jeong-Eun Lee, Steve Mairs, Doug Johnstone, Gregory J. Herczeg, Sung-ju Kang, Miju Kang, Jungyeon Cho, and Team, The JCMT Transient

Subjects
STELLAR evolution, ACCRETION (Astrophysics), STELLAR luminosity function, STAR formation, ASTROPHYSICS
Abstract

During the protostellar phase of stellar evolution, accretion onto the star is expected to be variable, but this suspected variability has been difficult to detect because protostars are deeply embedded. In this paper, we describe a submillimeter luminosity burst of the Class I protostar EC 53 in Serpens Main, the first variable found during our dedicated JCMT/SCUBA-2 monitoring program of eight nearby star-forming regions. EC 53 remained quiescent for the first six months of our survey, from 2016 February to August. The submillimeter emission began to brighten in 2016 September, reached a peak brightness of 1.5 times the faint state, and has been decaying slowly since 2017 February. The change in submillimeter brightness is interpreted as dust heating in the envelope, generated by a luminosity increase of the protostar of a factor of ≥4. The 850 μm light curve resembles the historical K-band light curve, which varies by a factor of ∼6 with a 543 period and is interpreted as accretion variability excited by interactions between the accretion disk and a close binary system. The predictable detections of accretion variability observed at both near-infrared and submillimeter wavelengths make the system a unique test-bed, enabling us to capture the moment of the accretion burst and to study the consequences of the outburst on the protostellar disk and envelope. [ABSTRACT FROM AUTHOR]

Published
2017
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25. How Do Stars Gain Their Mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions.

Author

Gregory J. Herczeg, Doug Johnstone, Steve Mairs, Jennifer Hatchell, Jeong-Eun Lee, Geoffrey C. Bower, Huei-Ru Vivien Chen, Yuri Aikawa, Hyunju Yoo, Sung-Ju Kang, Miju Kang, Wen-Ping Chen, Jonathan P. Williams, Jaehan Bae, Michael M. Dunham, Eduard I. Vorobyov, Zhaohuan Zhu, Ramprasad Rao, Helen Kirk, and Satoko Takahashi

Subjects
STAR formation, STELLAR evolution, PROTOSTARS, ACCRETION (Astrophysics), ASTROPHYSICS
Abstract

Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion—prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase is almost entirely unconstrained. In A James Clerk Maxwell Telescope/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions, we are monitoring monthly with SCUBA-2 the submillimeter emission in eight fields within nearby ( pc) star-forming regions to measure the accretion variability of protostars. The total survey area of ∼1.6 deg2 includes ∼105 peaks with peaks brighter than 0.5 Jy/beam (43 associated with embedded protostars or disks) and 237 peaks of 0.125–0.5 Jy/beam (50 with embedded protostars or disks). Each field has enough bright peaks for flux calibration relative to other peaks in the same field, which improves upon the nominal flux calibration uncertainties of submillimeter observations to reach a precision of ∼2%–3% rms, and also provides quantified confidence in any measured variability. The timescales and amplitudes of any submillimeter variation will then be converted into variations in accretion rate and subsequently used to infer the physical causes of the variability. This survey is the first dedicated survey for submillimeter variability and complements other transient surveys at optical and near-IR wavelengths, which are not sensitive to accretion variability of deeply embedded protostars. [ABSTRACT FROM AUTHOR]

Published
2017
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26. A Comparative Observational Study of YSO Classification in Four Small Star-forming H ii Regions.

Author

Sung-Ju Kang, C. R. Kerton, Minho Choi, and Miju Kang

Subjects
*STAR formation, *SPECTRAL energy distribution, *MOLECULAR clouds, *STAR observations
Abstract

We have developed a new young stellar object (YSO) identification and classification technique using mid-infrared Wide-field Infrared Survey Explorer (WISE) data. We compare this new technique with previous WISE YSO detection and classification methods that used either infrared colors or spectral energy distribution slopes. In this study, we also use the new technique to detect and examine the YSO population associated with four small H ii regions: KR 7, KR 81, KR 120, and KR 140. The relatively simple structure of these regions allows us to effectively use both spatial and temporal constraints to identify YSOs that are potential products of triggered star formation. We are also able to identify regions of active star formation around these H ii regions that are clearly not influenced by the H ii region expansion, and thus demonstrate that star formation is on-going on megayear timescales in some of these molecular clouds. [ABSTRACT FROM AUTHOR]

Published
2017
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