First BISTRO Observations of the Dark Cloud Taurus L1495A-B10: The Role of the Magnetic Field in the Earliest Stages of Low-mass Star Formation
Authors: Ward-Thompson Derek , Karoly Janik , Pattle Kate , Whitworth Anthony , Kirk Jason , Berry David , Bastien Pierre , Ching Tao-Chung , Coudé Simon , Hwang Jihye , Kwon Woojin , Soam Archana , Wang Jia-Wei , Hasegawa Tetsuo , Lai Shih-Ping , Qiu Keping , Arzoumanian Doris , Bourke Tyler L. , Byun Do-Young , Chen Huei-Ru Vivien , Chen Wen Ping , Chen Mike , Chen Zhiwei , Cho Jungyeon , Choi Minho , Choi Youngwoo , Choi Yunhee , Chrysostomou Antonio , Chung Eun Jung , Dai Sophia , Debattista Victor , Di Francesco James , Diep Pham Ngoc , Doi Yasuo , Duan Hao-Yuan , Duan Yan , Eswaraiah Chakali , Fanciullo Lapo , Fiege Jason , Fissel Laura M. , Franzmann Erica , Friberg Per , Friesen Rachel , Fuller Gary , Furuya Ray , Gledhill Tim , Graves Sarah , Greaves Jane , Griffin Matt , Gu Qilao , Han Ilseung , Hayashi Saeko , Hoang Thiem , Houde Martin , Hull Charles L. H. , Inoue Tsuyoshi , Inutsuka Shu-ichiro , Iwasaki Kazunari , Jeong Il-Gyo , Johnstone Doug , Könyves Vera , Kang Ji-hyun , Kang Miju , Kataoka Akimasa , Kawabata Koji , Kemper Francisca , Kim Jongsoo , Kim Shinyoung , Kim Gwanjeong , Kim Kyoung Hee , Kim Mi-Ryang , Kim Kee-Tae , Kim Hyosung , Kirchschlager Florian , Kobayashi Masato I. N. , Koch Patrick M. , Kusune Takayoshi , Kwon Jungmi , Lacaille Kevin , Law Chi-Yan , Lee Chang Won , Lee Hyeseung , Lee Yong-Hee , Lee Chin-Fei , Lee Jeong-Eun , Lee Sang-Sung , Li Dalei , Li Di , Li Guangxing , Li Hua-bai , Lin Sheng-Jun , Liu Hong-Li , Liu Tie , Liu Sheng-Yuan , Liu Junhao , Longmore Steven , Lu Xing , Lyo A-Ran , Mairs Steve , Matsumura Masafumi , Matthews Brenda , Moriarty-Schieven Gerald , Nagata Tetsuya , Nakamura Fumitaka , Nakanishi Hiroyuki , Ngoc Nguyen Bich , Ohashi Nagayoshi , Onaka Takashi , Park Geumsook , Parsons Harriet , Peretto Nicolas , Priestley Felix , Pyo Tae-Soo , Qian Lei , Rao Ramprasad , Rawlings Jonathan , Rawlings Mark , Retter Brendan , Richer John , Rigby Andrew , Sadavoy Sarah , Saito Hiro , Savini Giorgio , Seta Masumichi , Shimajiri Yoshito , Shinnaga Hiroko , Tahani Mehrnoosh , Tamura Motohide , Tang Ya-Wen , Tang Xindi , Tomisaka Kohji , Tram Le Ngoc , Tsukamoto Yusuke , Viti Serena , Wang Hongchi , Wu Jintai , Xie Jinjin , Yang Meng-Zhe , Yen Hsi-Wei , Yoo Hyunju , Yuan Jinghua , Yun Hyeong-Sik , Zenko Tetsuya , Zhang Guoyin , Zhang Yapeng , Zhang Chuan-Peng , Zhou Jianjun , Zhu Lei , de Looze Ilse , André Philippe , Dowell C. Darren , Eden David , Eyres Stewart , Falle Sam , Le Gouellec Valentin J. M. , Poidevin Frédérick , Robitaille Jean-François , van Loo Sven 
Published: March 2023

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