Author: "THOMPSON, DEREK" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"THOMPSON, DEREK"' showing total 1,253 results

Start Over Author "THOMPSON, DEREK"

1,253 results on '"THOMPSON, DEREK"'

1. Herschel Gould Belt Survey in Taurus. II: A census of dense cores and filaments in the TMC1 region

Author: Kirk, Jason, Ward-Thompson, Derek, Di Francesco, James, André, Philippe, Bresnahan, David, Könyves, Vera, Marsh, Kenneth, Griffin, Matt, Schneider, Nicola, Men'shchikov, A., Palmeirim, Pedro, Bontemps, Sylvain, Arzoumanian, Doris, Benedettini, Milena, and Pezzuto, Stefania
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present a catalogue of dense cores and filaments in a $3.8^{\circ}\times2.4^{\circ}$ field around the TMC1 region of the Taurus Molecular Cloud. The catalogue was created using photometric data from the Herschel SPIRE and PACS instruments in the 70 $\mu$m, 160 $\mu$m, 250 $\mu$m, 350 $\mu$m, and 500 $\mu$m continuum bands. Extended structure in the region was reconstructed from a Herschel column density map. Power spectra and PDFs of this structure are presented. The PDF splits into log-normal and power-law forms, with the high-density power-law component associated primarily with the central part of TMC1. The total mass in the mapped region is 2000 M$_\odot$, of which 34% is above an extinction of AV $\sim$ 3 mag -- a level that appears as a break in the PDF and as the minimum column density at which dense cores are found. A total of 35 dense filaments were extracted from the column density map. These have a characteristic FWHM width of 0.07 pc, but the TMC1 filament itself has a mean FWHM of $\sim$ 0.13 pc. The thermally supercritical filaments in the region are aligned orthogonal to the prevailing magnetic field direction. Derived properties for the supercritical TMC1 filament support the scenario of it being relatively young. A catalogue of 44 robust and candidate prestellar cores is created and is assessed to be complete down to 0.1 M$_\odot$. The combined prestellar CMF for the TMC1 and L1495 regions is well fit by a single log-normal distribution and is comparable to the standard IMF., Comment: 21 pages, 23 figures, accepted for publication in MNRAS. For data products see http://gouldbelt-herschel.cea.fr/archives
Published: 2024

2. On the Scarcity of Dense Cores ($n>10^{5}$ cm$^{-3}$) in High Latitude Planck Galactic Cold Clumps

Author: Xu, Fengwei, Wang, Ke, Liu, Tie, Eden, David, Liu, Xunchuan, Juvela, Mika, He, Jinhua, Johnstone, Doug, Goldsmith, Paul, Garay, Guido, Wu, Yuefang, Soam, Archana, Traficante, Alessio, Ristorcelli, Isabelle, Falgarone, Edith, Chen, Huei-Ru Vivien, Hirano, Naomi, Doi, Yasuo, Kwon, Woojin, White, Glenn J., Whitworth, Anthony, Sanhueza, Patricio, Rawlings, Mark G., Alina, Dana, Ren, Zhiyuan, Lee, Chang Won, Tatematsu, Ken'ichi, Zhang, Chuan-Peng, Zhou, Jianjun, Lai, Shih-Ping, Ward-Thompson, Derek, Liu, Sheng-Yuan, Gu, Qilao, Chakali, Eswaraiah, Zhu, Lei, Mardones, Diego, and Tóth, L. Viktor
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: High-latitude ($|b|>30^{\circ}$) molecular clouds have virial parameters that exceed 1, but whether these clouds can form stars has not been studied systematically. Using JCMT SCUBA-2 archival data, we surveyed 70 fields that target high-latitude Planck galactic cold clumps (HLPCs) to find dense cores with density of $10^{5}$-$10^{6}$ cm$^{-3}$ and size of $<0.1$ pc. The sample benefits from both the representativeness of the parent sample and covering densest clumps at the high column density end ($>1\times10^{21}$ cm$^{-2}$). At an average noise rms of 15 mJy/beam, we detected Galactic dense cores in only one field, G6.04+36.77 (L183), while also identifying 12 extragalactic objects and two young stellar objects. Compared to the low-latitude clumps, dense cores are scarce in HLPCs. With synthetic observations, the densities of cores are constrained to be $n_c\lesssim10^5$ cm$^{-3}$, should they exist in HLPCs. Low-latitude clumps, Taurus clumps, and HLPCs form a sequence where a higher virial parameter corresponds to a lower dense core detection rate. If HLPCs were affected by the Local Bubble, the scarcity should favor turbulence-inhibited rather than supernova-driven star formation. Studies of the formation mechanism of the L183 molecular cloud are warranted., Comment: 9 pages for the main text. 4 figures, 1 table. Published in Astrophysical Journal Letter
Published: 2024
Full Text: View/download PDF

3. Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-Mass Star-Forming Region NGC2264 : Global Properties and Local Magnetogravitational Configurations

Author: Wang, Jia-Wei, Koch, Patrick M., Clarke, Seamus D., Fuller, Gary, Peretto, Nicolas, Tang, Ya-Wen, Yen, Hsi-Wei, Lai, Shih-Ping, Ohashi, Nagayoshi, Arzoumanian, Doris, Johnstone, Doug, Furuya, Ray, Inutsuka, Shu-ichiro, Lee, Chang Won, Ward-Thompson, Derek, Gouellec, Valentin J. M. Le, Liu, Hong-Li, Fanciullo, Lapo, Hwang, Jihye, Pattle, Kate, Poidevin, Frédérick, Tahani, Mehrnoosh, Onaka, Takashi, Rawlings, Mark G., Chung, Eun Jung, Liu, Junhao, Lyo, A-Ran, Priestley, Felix, Hoang, Thiem, Tamura, Motohide, Berry, David, Bastien, Pierre, Ching, Tao-Chung, Coudé, Simon, Kwon, Woojin, Chen, Mike, Eswaraiah, Chakali, Soam, Archana, Hasegawa, Tetsuo, Qiu, Keping, Bourke, Tyler L., Byun, Do-Young, Chen, Zhiwei, Chen, Huei-Ru Vivien, Chen, Wen Ping, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Choi, Youngwoo, Chrysostomou, Antonio, Dai, Sophia, Di Francesco, James, Diep, Pham Ngoc, Doi, Yasuo, Duan, Yan, Duan, Hao-Yuan, Eden, David, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hayashi, Saeko, Houde, Martin, Inoue, Tsuyoshi, Iwasaki, Kazunari, Jeong, Il-Gyo, Könyves, Vera, Kang, Ji-hyun, Kang, Miju, Karoly, Janik, Kataoka, Akimasa, Kawabata, Koji, Khan, Zacariyya, Kim, Mi-Ryang, Kim, Kee-Tae, Kim, Kyoung Hee, Kim, Shinyoung, Kim, Jongsoo, Kim, Hyosung, Kim, Gwanjeong, Kirchschlager, Florian, Kirk, Jason, Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Law, Chi-Yan, Lee, Sang-Sung, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Chin-Fei, Li, Dalei, Li, Hua-bai, Li, Guangxing, Li, Di, Lin, Sheng-Jun, Liu, Tie, Liu, Sheng-Yuan, Lu, Xing, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Park, Geumsook, Parsons, Harriet, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Jonathan, Retter, Brendan, Richer, John, Rigby, Andrew, Sadavoy, Sarah, Saito, Hiro, Savini, Giorgio, Seta, Masumichi, Sharma, Ekta, Shimajiri, Yoshito, Shinnaga, Hiroko, Tang, Xindi, Thuong, Hoang Duc, Tomisaka, Kohji, Tram, Le Ngoc, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Whitworth, Anthony, Wu, Jintai, Xie, Jinjin, Yang, Meng-Zhe, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Chuan-Peng, Zhang, Yapeng, Zhang, Guoyin, Zhou, Jianjun, Zhu, Lei, de Looze, Ilse, André, Philippe, Dowell, C. Darren, Eyres, Stewart, Falle, Sam, Robitaille, Jean-François, and van Loo, Sven
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We report 850 $\mu$m continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B-fields In STar forming Regions Observations (BISTRO) large program on the James Clerk Maxwell Telescope (JCMT). These data reveal a well-structured non-uniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30 deg from north to east. Field strengths estimates and a virial analysis for the major clumps indicate that NGC 2264C is globally dominated by gravity while in 2264D magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type-I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type-II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and the longitudinal collapsing, driven by the region's global gravity., Comment: Accepted for publication in the Astrophysical Journal. 43 pages, 32 figures, and 4 tables (including Appendix)
Published: 2024

4. Magnetic fields of the starless core L 1512

Author: Lin, Sheng-Jun, Lai, Shih-Ping, Pattle, Kate, Berry, David, Clemens, Dan P., Pagani, Laurent, Ward-Thompson, Derek, Thieme, Travis J., and Ching, Tao-Chung
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present JCMT POL-2 850 um dust polarization observations and Mimir H band stellar polarization observations toward the starless core L1512. We detect the highly-ordered core-scale magnetic field traced by the POL-2 data, of which the field orientation is consistent with the parsec-scale magnetic fields traced by Planck data, suggesting the large-scale fields thread from the low-density region to the dense core region in this cloud. The surrounding magnetic field traced by the Mimir data shows a wider variation in the field orientation, suggesting there could be a transition of magnetic field morphology at the envelope scale. L1512 was suggested to be presumably older than 1.4 Myr in a previous study via time-dependent chemical analysis, hinting that the magnetic field could be strong enough to slow the collapse of L1512. In this study, we use the Davis-Chandrasekhar-Fermi method to derive a plane-of-sky magnetic field strength ($B_{pos}$) of 18$\pm$7 uG and an observed mass-to-flux ratio ($\lambda_{obs}$) of 3.5$\pm$2.4, suggesting that L1512 is magnetically supercritical. However, the absence of significant infall motion and the presence of an oscillating envelope are inconsistent with the magnetically supercritical condition. Using a Virial analysis, we suggest the presence of a hitherto hidden line-of-sight magnetic field strength of ~27 uG with a mass-to-flux ratio ($\lambda_{tot}$) of ~1.6, in which case both magnetic and kinetic pressures are important in supporting the L1512 core. On the other hand, L1512 may have just reached supercriticality and will collapse at any time., Comment: 25 pages, 10 figures, accepted for publication in ApJ
Published: 2023

5. A search for pulsars around Sgr A* in the first Event Horizon Telescope dataset

Author: Torne, Pablo, Liu, Kuo, Eatough, Ralph P., Wongphechauxsorn, Jompoj, Cordes, James M., Desvignes, Gregory, De Laurentis, Mariafelicia, Kramer, Michael, Ransom, Scott M., Chatterjee, Shami, Wharton, Robert, Karuppusamy, Ramesh, Blackburn, Lindy, Janssen, Michael, Chan, Chi-kwan, Crew, Geoffrey B., Matthews, Lynn D., Goddi, Ciriaco, Rottmann, Helge, Wagner, Jan, Sanchez, Salvador, Ruiz, Ignacio, Abbate, Federico, Bower, Geoffrey C., Salamanca, Juan J., Gomez-Ruiz, Arturo I., Herrera-Aguilar, Alfredo, Jiang, Wu, Lu, Ru-Sen, Pen, Ue-Li, Raymond, Alexander W., Shao, Lijing, Shen, Zhiqiang, Paubert, Gabriel, Sanchez-Portal, Miguel, Kramer, Carsten, Castillo, Manuel, Navarro, Santiago, John, David, Schuster, Karl-Friedrich, Johnson, Michael D., Rygl, Kazi L. J., Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Bach, Uwe, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Bauboeck, Michi, Benson, Bradford A., Bintley, Dan, Blundell, Raymond, Bouman, Katherine L., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E., Ceccobello, Chiara, Chael, Andrew, Chang, Dominic O., Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Crawford, Thomas M., Cruz-Osorio, Alejandro, Cui, Yuzhu, Dahale, Rohan, Davelaar, Jordy, Deane, Roger, Dempsey, Jessica, Dexter, Jason, Dhruv, Vedant, Doeleman, Sheperd S., Dougal, Sean, Dzib, Sergio A., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Foschi, Marianna, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Gold, Roman, Gomez, Jose L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Haworth, Kari, Hecht, Michael H., Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Impellizzeri, C. M. Violette, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Jeter, Britton, Jimenez-Rosales, Alejandra, Jorstad, Svetlana, Joshi, Abhishek V., Jung, Taehyun, Karami, Mansour, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kocherlakota, Prashant, Kofuji, Yutaro, Koyama, Shoko, Krichbaum, Thomas P., Kuo, Cheng-Yu, La Bella, Noemi, Lauer, Tod R., Lee, Daeyoung, Lee, Sang-Sung, Leung, Po Kin, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin J., MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Marti-Vidal, Ivan, Matsushita, Satoki, Medeiros, Lia, Menten, Karl M., Michalik, Daniel, Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Muller, Cornelia, Muller, Hendrik, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nadolski, Andrew, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Ozel, Feryal, Palumbo, Daniel C. M., Paraschos, Georgios Filippos, Park, Jongho, Parsons, Harriet, Patel, Nimesh, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Potzl, Felix M., Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Rezzolla, Luciano, Ricarte, Angelo, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Romero-Cañizales, Cristina, Roshanineshat, Arash, Roy, Alan L., Ruszczyk, Chet, Sanchez-Arguelles, David, Sasada, Mahito, Satapathy, Kaushik, Savolainen, Tuomas, Schloerb, F. Peter, Schonfeld, Jonathan, Small, Des, Sohn, Bong Won, SooHoo, Jason, Souccar, Kamal, Sun, He, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toscano, Teresa, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Vos, Jesse, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wielgus, Maciek, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wong, George N., Wu, Qingwen, Yadlapalli, Nitika, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Young, Andre, Young, Ken, Younsi, Ziri, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, and Zhao, Shan-Shan
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The Event Horizon Telescope (EHT) observed in 2017 the supermassive black hole at the center of the Milky Way, Sagittarius A* (Sgr A*), at a frequency of 228.1 GHz ($\lambda$=1.3 mm). The fundamental physics tests that even a single pulsar orbiting Sgr A* would enable motivate searching for pulsars in EHT datasets. The high observing frequency means that pulsars - which typically exhibit steep emission spectra - are expected to be very faint. However, it also negates pulse scattering, an effect that could hinder pulsar detections in the Galactic Center. Additionally, magnetars or a secondary inverse Compton emission could be stronger at millimeter wavelengths than at lower frequencies. We present a search for pulsars close to Sgr A* using the data from the three most-sensitive stations in the EHT 2017 campaign: the Atacama Large Millimeter/submillimeter Array, the Large Millimeter Telescope and the IRAM 30 m Telescope. We apply three detection methods based on Fourier-domain analysis, the Fast-Folding-Algorithm and single pulse search targeting both pulsars and burst-like transient emission; using the simultaneity of the observations to confirm potential candidates. No new pulsars or significant bursts were found. Being the first pulsar search ever carried out at such high radio frequencies, we detail our analysis methods and give a detailed estimation of the sensitivity of the search. We conclude that the EHT 2017 observations are only sensitive to a small fraction ($\lesssim$2.2%) of the pulsars that may exist close to Sgr A*, motivating further searches for fainter pulsars in the region., Comment: 33 pages, 7 figures, 6 Tables. Accepted for publication in ApJ
Published: 2023

6. Characterising a World Within the Hot Neptune Desert: Transit Observations of LTT 9779 b with HST WFC3

Author: Edwards, Billy, Changeat, Quentin, Tsiaras, Angelos, Allan, Andrew, Behr, Patrick, Hagey, Simone R., Himes, Michael D., Ma, Sushuang, Stassun, Keivan G., Thomas, Luis, Thompson, Alexandra, Boley, Aaron, Booth, Luke, Bouwman, Jeroen, France, Kevin, Lowson, Nataliea, Meech, Annabella, Phillips, Caprice L., Vidotto, Aline A., Yip, Kai Hou, Bieger, Michelle, Gressier, Amelie, Janin, Estelle, Jiang, Ing-Guey, Leonardi, Pietro, Sarkar, Subhajit, Skaf, Nour, Taylor, Jake, Yang, Ming, and Ward-Thompson, Derek
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: We present an atmospheric analysis of LTT 9779 b, a rare planet situated in the hot Neptune desert, that has been observed with HST WFC3 G102 and G141. The combined transmission spectrum, which covers 0.8 - 1.6 $\mu$m, shows a gradual increase in transit depth with wavelength. Our preferred atmospheric model shows evidence for H$_{\rm 2}$O, CO$_{\rm 2}$ and FeH with a significance of 3.1 $\sigma$, 2.4 $\sigma$ and 2.1 $\sigma$, respectively. In an attempt to constrain the rate of atmospheric escape for this planet, we search for the 1.083 $\mu$m Helium line in the G102 data but find no evidence of excess absorption that would indicate an escaping atmosphere using this tracer. We refine the orbital ephemerides of LTT 9779 b using our HST data and observations from TESS, searching for evidence of orbital decay or apsidal precession, which is not found. The phase-curve observation of LTT 9779 b with JWST NIRISS should provide deeper insights into the atmosphere of this planet and the expected atmospheric escape might be detected with further observations concentrated on other tracers such as Lyman $\alpha$., Comment: Accepted for publication in AJ
Published: 2023

7. Stellar clustering and the kinematics of stars around Collinder 121 using Gaia DR3

Author: Fleming, Graham D., Kirk, Jason M., and Ward-Thompson, Derek
Subjects: Astrophysics - Astrophysics of Galaxies, Physics - Space Physics
Abstract: We study the region around Collinder 121 (Cr 121) using newly available 6-dimensional data from the Gaia DR3 catalogue. Situated in the third quadrant, near the galactic plane, Collinder 121 lies in the region of Canis Major centred around l = 236 degrees, b = -10 degrees. Previous studies have suggested that the stellar associations in this region comprise an OB association (CMa OB2) lying at about 740 pc with a more distant open cluster (Cr 121) at approximately 1170 pc. Despite these studies, the precise nature of Collinder 121 remains uncertain. This study investigates the region bounded by the box l = 225 to 245 degrees, b = 0.00 to -20.00 degrees to a depth of 700 pc from 500 to 1200 pc which fully encompasses the region discussed in the literature. Using Gaia DR3 data, we do not find associations at the distances given in the literature. Instead, using the HDBSCAN machine learning algorithm, we find a major association of OB stars centred around 803 pc. Within this association we find four smaller subgroups that may be indicative of a larger association and which are located at a mean distance of 827 pc. Proper motion studies find coherence between these four subgroups and show a distinctive east to west increase in the size of the velocity vectors which supports contemporary studies that show similar trends in OB populations in Cygnus and within the Carina spiral Arm. Therefore, we hypothesize that Cr 121 and CMa OB2 are the same cluster, consistent with the 1977 study by Hoogerwerf.
Published: 2023
Full Text: View/download PDF

8. The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43

Author: Karoly, Janik, Ward-Thompson, Derek, Pattle, Kate, Berry, David, Whitworth, Anthony, Kirk, Jason, Bastien, Pierre, Ching, Tao-Chung, Coude, 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, Hoang, Thiem, Houde, Martin, Hull, Charles L. H., Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Johnstone, Doug, Konyves, 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, Sharma, Ekta, 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, Andre, Philippe, Dowell, C. Darren, Eden, David, Eyres, Stewart, Falle, Sam, Gouellec, Valentin J. M. Le, Poidevin, Frederick, Robitaille, Jean-Francois, and van Loo, Sven
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present observations of polarized dust emission at 850 $\mu$m from the L43 molecular cloud which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense ($N_{\rm H_2}\sim 10^{22}$-10$^{23}$ cm$^{-2}$) complex molecular cloud with a submillimetre-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to $\sim$160$\pm$30 $\mu$G in the main starless core and up to $\sim$90$\pm$40 $\mu$G in the more diffuse, extended region. These field strengths give magnetically super- and sub-critical values respectively and both are found to be roughly trans-Alfv\'enic. We also present a new method of data reduction for these denser but fainter objects like starless cores., Comment: Accepted for publication in ApJ. 23 pages, 9 figures (7 main text, 2 appendix)
Published: 2023
Full Text: View/download PDF

9. Comparison of Polarized Radiative Transfer Codes used by the EHT Collaboration

Author: Prather, Ben S., Dexter, Jason, Moscibrodzka, Monika, Pu, Hung-Yi, Bronzwaer, Thomas, Davelaar, Jordy, Younsi, Ziri, Gammie, Charles F., Gold, Roman, Wong, George N., Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Bach, Uwe, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Barrett, John, Bauböck, Michi, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E., Ceccobello, Chiara, Chael, Andrew, Chan, Chi-kwan, Chang, Dominic O., Chatterjee, Koushik, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dhruv, Vedant, Doeleman, Sheperd S., Dougal, Sean, Dzib, Sergio A., Eatough, Ralph P., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, García, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gómez-Ruiz, Arturo I., Gómez, José L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Haworth, Kari, Hecht, Michael H., Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Impellizzeri, C. M. Violette, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Johnson, Michael D., Jorstad, Svetlana, Joshi, Abhishek V., Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kocherlakota, Prashant, Kofuji, Yutaro, Koyama, Shoko, Kramer, Carsten, Kramer, Michael, Krichbaum, Thomas P., Kuo, Cheng-Yu, La Bella, Noemi, Lauer, Tod R., Lee, Daeyoung, Lee, Sang-Sung, Leung, Po Kin, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin J., Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Iván, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Michalik, Daniel, Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Müller, Cornelia, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nadolski, Andrew, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Fuentes, Santiago Navarro, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Olivares, Héctor, Ortiz-León, Gisela N., Oyama, Tomoaki, Özel, Feryal, Palumbo, Daniel C. M., Paraschos, Georgios Filippos, Park, Jongho, Parsons, Harriet, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Piétu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Pötzl, Felix M., Preciado-López, Jorge A., Psaltis, Dimitrios, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ricarte, Angelo, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Romero-Cañizales, Cristina, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruiz, Ignacio, Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez, Salvador, Sánchez-Argüelles, David, Sánchez-Portal, Miguel, Sasada, Mahito, Satapathy, Kaushik, Savolainen, Tuomas, Schloerb, F. Peter, Schonfeld, Jonathan, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Souccar, Kamal, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Vos, Jesse, Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wu, Qingwen, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Young, André, Young, Ken, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, and Zhao, Shan-Shan
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Interpretation of resolved polarized images of black holes by the Event Horizon Telescope (EHT) requires predictions of the polarized emission observable by an Earth-based instrument for a particular model of the black hole accretion system. Such predictions are generated by general relativistic radiative transfer (GRRT) codes, which integrate the equations of polarized radiative transfer in curved spacetime. A selection of ray-tracing GRRT codes used within the EHT collaboration is evaluated for accuracy and consistency in producing a selection of test images, demonstrating that the various methods and implementations of radiative transfer calculations are highly consistent. When imaging an analytic accretion model, we find that all codes produce images similar within a pixel-wise normalized mean squared error (NMSE) of 0.012 in the worst case. When imaging a snapshot from a cell-based magnetohydrodynamic simulation, we find all test images to be similar within NMSEs of 0.02, 0.04, 0.04, and 0.12 in Stokes I, Q, U , and V respectively. We additionally find the values of several image metrics relevant to published EHT results to be in agreement to much better precision than measurement uncertainties., Comment: Accepted for publication in ApJ
Published: 2023
Full Text: View/download PDF

10. First BISTRO observations of the dark cloud Taurus L1495A-B10: the role of the magnetic field in the earliest stages of low-mass star formation

Author: Ward-Thompson, Derek, Karoly, Janik, Pattle, Kate, Whitworth, Anthony, Kirk, Jason, Berry, David, Bastien, Pierre, Ching, Tao-Chung, Coude, 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, Konyves, 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, Andre, Philippe, Dowell, C. Darren, Eden, David, Eyres, Stewart, Falle, Sam, Gouellec, Valentin J. M. Le, Poidevin, Frederick, Robitaille, Jean-Francois, and van Loo, Sven
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present BISTRO Survey 850 {\mu}m dust emission polarisation observations of the L1495A-B10 region of the Taurus molecular cloud, taken at the JCMT. We observe a roughly triangular network of dense filaments. We detect 9 of the dense starless cores embedded within these filaments in polarisation, 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 years (Mestel 1965)., Comment: 14 pages, 5 figures. ApJ accepted
Published: 2023
Full Text: View/download PDF

11. A low-mass hub-filament with double centre revealed in NGC2071-North

Author: Könyves, Vera, Ward-Thompson, Derek, Shimajiri, Yoshito, Palmeirim, Pedro, and André, Philippe
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the first analysis in NGC2071-North as a resolved hub-filament featuring a double centre. This $\sim 1.5 \times 1.5$ parsec-scale filament hub contains $\sim$500 $M_\odot$. Seen from Planck, magnetic field lines may have facilitated the gathering of material at this isolated location. The energy balance analysis, supported by infalling gas signatures, reveal that these filaments are currently forming stars. Herschel 100 $\mu$m emission concentrates in the hub, at IRAS 05451+0037 and LkH$\alpha$ 316, and presents diffuse lobes and loops around them. We suggest that such a double centre could be formed, because the converging locations of filament pairs are offset, by 2.3$'$ (0.27 pc). This distance also matches the diameter of a hub-ring, seen in column density and molecular tracers, such as HCO$^+$(1$-$0) and HCN(1$-$0), that may indicate a transition and the connection between the hub and the radiating filaments. We argue that all of the three components of the emission star LkH$\alpha$ 316 are in physical association. We find that a $\sim$0.06 pc-sized gas loop, attached to IRAS 05451+0037, can be seen at wavelengths all the way from Pan-STARRS-i to Herschel-100 $\mu$m. These observations suggest that both protostars at the double hub centre are interacting with the cloud material. In our $^{13}$CO data, we do not seem to find the outflow of this region that was identified in the 80s with much lower resolution., Comment: 18 pages, 12 figures, accepted for publication in the MNRAS
Published: 2023
Full Text: View/download PDF

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

Author: Tahani, Mehrnoosh, Bastien, Pierre, Furuya, Ray S., Pattle, Kate, Johnstone, Doug, Arzoumanian, Doris, Doi, Yasuo, Hasegawa, Tetsuo, Inutsuka, Shu-ichiro, Coudé, Simon, Fissel, Laura, Chen, Michael Chun-Yuan, Poidevin, Frédérick, Sadavoy, Sarah, Friesen, Rachel, Koch, Patrick M., Di Francesco, James, Moriarty-Schieven, Gerald H., Chen, Zhiwei, Chung, Eun Jung, Eswaraiah, Chakali, Fanciullo, Lapo, Gledhill, Tim, Gouellec, Valentin J. M. Le, Hoang, Thiem, Hwang, Jihye, Kang, Ji-hyun, Kim, Kyoung Hee, Kirchschlager, Florian, Kwon, Woojin, Lee, Chang Won, Liu, Hong-Li, Onaka, Takashi, Rawlings, Mark G., Soam, Archana, Tamura, Motohide, Tang, Xindi, Tomisaka, Kohji, Whitworth, Anthony P., Kwon, Jungmi, Hoang, Thuong D., Redman, Matt, Berry, David, Ching, Tao-Chung, Wang, Jia-Wei, Lai, Shih-Ping, Qiu, Keping, Ward-Thompson, Derek, Houde, Martin, Byun, Do-Young, Chen, Huei-Ru Vivien, Chen, Wen Ping, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Chrysostomou, Antonio, Diep, Pham Ngoc, Duan, Hao-Yuan, Fiege, Jason, Franzmann, Erica, Friberg, Per, Fuller, Gary, Graves, Sarah F., Greaves, Jane S., Griffin, Matt J., Gu, Qilao, Han, Ilseung, Hatchell, Jennifer, Hayashi, Saeko S., Hull, Charles L. H., Inoue, Tsuyoshi, Iwasaki, Kazunari, Jeong, Il-Gyo, Kanamori, Yoshihiro, Kang, Miju, Kang, Sung-ju, Kataoka, Akimasa, Kawabata, Koji S., Kemper, Francisca, Kim, Gwanjeong, Kim, Jongsoo Hee, Kim, Kee-Tae, Kim, Mi-Ryang, Kim, Shinyoung, Kirk, Jason M., Kobayashi, Masato I. N., Konyves, Vera, Kusune, Takayoshi, Lacaille, Kevin, Law, Chi-Yan, Lee, Chin-Fei, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Sang-Sung, Lee, Yong-Hee, Li, Dalei, Li, Di, Li, Hua-bai, Liu, Junhao, Liu, Sheng-Yuan, Liu, Tie, de Looze, Ilse, Lyo, A-Ran, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda C., Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ohashi, Nagayoshi, Park, Geumsook, Parsons, Harriet, Peretto, Nicolas, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Scaife, Anna M. M., Seta, Masumichi, Shimajiri, Yoshito, Shinnaga, Hiroko, Tang, Ya-Wen, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Yen, Hsi-Wei, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Chuan-Peng, Zhang, Guoyin, Zhang, Yapeng, Zhou, Jianjun, Zhu, Lei, André, Philippe, Dowell, C. Darren, Eyres, Stewart P. S., Falle, Sam, van Loo, Sven, and Robitaille, Jean-François
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We study the HII regions associated with the NGC 6334 molecular cloud observed in the sub-millimeter and taken as part of the B-fields In STar-forming Region Observations (BISTRO) Survey. In particular, we investigate the polarization patterns and magnetic field morphologies associated with these HII 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 HII 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., Comment: Accepted for publication in Astrophysical Journal (ApJ)
Published: 2022
Full Text: View/download PDF

13. Closed-range posinormal operators and their products

Author: Bourdon, Paul, Kubrusly, Carlos, Le, Trieu, and Thompson, Derek
Subjects: Mathematics - Functional Analysis, Primary 47B20, Secondary 47B15
Abstract: We focus on two problems relating to the question of when the product of two posinormal operators is posinormal, giving (1) necessary conditions and sufficient conditions for posinormal operators to have closed range, and (2) sufficient conditions for the product of commuting closed-range posinormal operators to be posinormal with closed range. We also discuss the relationship between posinormal operators and EP operators (as well as hypo-EP operators), concluding with a new proof of the Hartwig-Katz Theorem, which characterizes when the product of posinormal operators on $\CC^n$ is posinormal.
Published: 2022

14. The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament

Author: Ching, Tao-Chung, Qiu, Keping, Li, Di, Ren, Zhiyuan, Lai, Shih-Ping, Berry, David, Pattle, Kate, Furuya, Ray, Ward-Thompson, Derek, Johnstone, Doug, Koch, Patrick M., Lee, Chang Won, Hoang, Thiem, Hasegawa, Tetsuo, Kwon, Woojin, Bastien, Pierre, Eswaraiah, Chakali, Wang, Jia-Wei, Kim, Kyoung Hee, Hwang, Jihye, Soam, Archana, Lyo, A-Ran, Liu, Junhao, Gouellec, Valentin J. M. Le, Arzoumanian, Doris, Whitworth, Anthony, Di Francesco, James, Poidevin, Frederick, Liu, Tie, Coude, Simon, Tahani, Mehrnoosh, Liu, Hong-Li, Onaka, Takashi, Li, Dalei, Tamura, Motohide, Chen, Zhiwei, Tang, Xindi, Kirchschlager, Florian, Bourke, Tyler L., Byun, Do-Young, Chen, Mike, Chen, Huei-Ru Vivien, Chen, Wen Ping, Cho, Jungyeon, Choi, Yunhee, Choi, Youngwoo, Choi, Minho, Chrysostomou, Antonio, Chung, Eun Jung, Dai, Y. Sophia, Diep, Pham Ngoc, Doi, Yasuo, Duan, Yan, Duan, Hao-Yuan, Eden, David, Fanciullo, Lapo, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Fuller, Gary, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hayashi, Saeko, Houde, Martin, Hull, Charles L. H., Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Konyves, Vera, Kang, Ji-hyun, Kang, Miju, Karoly, Janik, Kataoka, Akimasa, Kawabata, Koji, Kemper, Francisca, Kim, Jongsoo, Kim, Mi-Ryang, Kim, Shinyoung, Kim, Hyosung, Kim, Kee-Tae, Kim, Gwanjeong, Kirk, Jason, Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Law, Chi-Yan, Lee, Sang-Sung, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Chin-Fei, Lee, Yong-Hee, Li, Guangxing, Li, Hua-bai, Lin, Sheng-Jun, Liu, Sheng-Yuan, Lu, Xing, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Ohashi, Nagayoshi, Park, Geumsook, Parsons, Harriet, Peretto, Nicolas, Priestley, Felix, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Mark, Rawlings, Jonathan, Retter, Brendan, Richer, John, Rigby, Andrew, Sadavoy, Sarah, Saito, Hiro, Savini, Giorgio, Seta, Masumichi, Shimajiri, Yoshito, Shinnaga, Hiroko, Tang, Ya-Wen, 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, Chuan-Peng, Zhang, Yapeng, Zhang, Guoyin, Zhou, Jianjun, Zhu, Lei, de Looze, Ilse, Andre, Philippe, Dowell, C. Darren, Eyres, Stewart, Falle, Sam, Robitaille, Jean-Francois, and van Loo, Sven
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present 850 $\mu$m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the sub-filaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1--10 pc scales. The magnetic fields revealed in the Planck data are well aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6--1.0 mG in the DR21 filament and $\sim$ 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by JCMT. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and sub-filaments., Comment: 26 pages, 13 figures, ApJ accepted
Published: 2022
Full Text: View/download PDF

15. The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2

Author: Hwang, Jihye, Kim, Jongsoo, Pattle, Kate, Lee, Chang Won, Koch, Patrick M., Johnstone, Doug, Tomisaka, Kohji, Whitworth, Anthony, Furuya, Ray S., Kang, Ji-hyun, Lyo, A-Ran, Chung, Eun Jung, Arzoumanian, Doris, Park, Geumsook, Kwon, Woojin, Kim, Shinyoung, Tamura, Motohide, Kwon, Jungmi, Soam, Archana, Han, Ilseung, Hoang, Thiem, Kim, Kyoung Hee, Onaka, Takashi, Chakali, Eswaraiah, Ward-Thompson, Derek, Liu, Hong-Li, Tang, Xindi, Chen, Wen Ping, Matsumura, Masafumi, Hoang, Thuong Duc, Chen, Zhiwei, Gouellec, Valentin J. M. Le, Kirchschlager, Florian, Poidevin, Fr ed erick, Bastien, Pierre, Qiu, Keping, Hasegawa, Tetsuo, Lai, Shih-Ping, Byun, Do-Young, Cho, Jungyeon, Choi, Minho, Choi, Youngwoo, Choi, Yunhee, Jeong, Il-Gyo, Kang, Miju, Kim, Hyosung, Kim, Kee-tae, Lee, Jeong-Eun, Lee, Sang-sung, Lee, Yong-Hee, Lee, Hyeseung, Kim, Mi-Ryang, Yoo, Hyunju, Yun, Hyeong-Sik, Chen, Mike, Di Francesco, James, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Houde, Martin, Lacaille, Kevin, Matthews, Brenda, Sadavoy, Sarah, Moriarty-Schieven, Gerald, Tahani, Mehrnoosh, Ching, Tao-Chung, Dai, Y. Sophia, Duan, Yan, Gu, Qilao, Law, Chi-Yan, Li, Dalei, Li, Di, Li, Guangxing, Li, Hua-bai, Liu, Tie, Lu, Xing, Qian, Lei, Wang, Hongchi, Wu, Jintai, Xie, Jinjin, Yuan, Jinghua, Zhang, Chuan-Peng, Zhang, Guoyin, Zhang, Yapeng, Zhou, Jianjun, Zhu, Lei, Berry, David, Friberg, Per, Graves, Sarah, Liu, Junhao, Mairs, Steve, Parsons, Harriet, Rawlings, Mark, Doi, Yasuo, Hayashi, Saeko, Hull, Charles L. H., Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Kataoka, Akimasa, Kawabata, Koji, Kim, Gwanjeong, Kobayashi, Masato I. N., Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Pyo, Tae-Soo, Saito, Hiro, Seta, Masumichi, Shimajiri, Yoshito, Shinnaga, Hiroko, Tsukamoto, Yusuke, Zenko, Tetsuya, Chen, Huei-Ru Vivien, Duan, Hao-Yuan, Fanciullo, Lapo, Kemper, Francisca, Lee, Chin-Fei, Lin, Sheng-Jun, Liu, Sheng-Yuan, Ohashi, Nagayoshi, Rao, Ramprasad, Tang, Ya-Wen, Wang, Jia-Wei, Yang, Meng-Zhe, Yen, Hsi-Wei, Bourke, Tyler L., Chrysostomou, Antonio, Debattista, Victor, Eden, David, Eyres, Stewart, Falle, Sam, Fuller, Gary, Gledhill, Tim, Greaves, Jane, Griffin, Matt, Hatchell, Jennifer, Karoly, Janik, Kirk, Jason, Konyves, Vera, Longmore, Steven, van Loo, Sven, de Looze, Ilse, Peretto, Nicolas, Priestley, Felix, Rawlings, Jonathan, Retter, Brendan, Richer, John, Rigby, Andrew, Savini, Giorgio, Scaife, Anna, Viti, Serena, Diep, Pham Ngoc, Ngoc, Nguyen Bich, Tram, Le Ngoc, Andre, Philippe, Coude, Simon, Dowell, C. Darren, Friesen, Rachel, and Robitaille, Jean-Franc ois
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present and analyze observations of polarized dust emission at 850 $\mu$m towards the central 1 pc $\times$ 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the BISTRO (B-fields in Star-forming Region Observations) survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well-described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis-Chandrasekhar-Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from $Herschel$ data and the C$^{18}$O ($J$ = 3-2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 $\pm$ 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 $\pm$ 0.02. Additionally, the mean Alfv\'en Mach number is 0.35 $\pm$ 0.01. This suggests that in Mon R2, magnetic fields provide resistance against large-scale gravitational collapse, and magnetic pressure exceeds turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically sub-critical., Comment: This paper is accepted to the ApJ
Published: 2022
Full Text: View/download PDF

16. Twinkle -- a small satellite spectroscopy mission for the next phase of exoplanet science

Author: Stotesbury, Ian, Edwards, Billy, Lavigne, Jean-Francois, Pesquita, Vasco, Veilleux, James J., Windred, Philip, Al-Refaie, Ahmed, Bradley, Lawrence, Ma, Sushuang, Savini, Giorgio, Tinetti, Giovanna, Birnstiel, Til, Dodson-Robinson, Sally, Ercolano, Barbara, Feliz, Dax, Gaudi, Scott, Hernitschek, Nina, Holdsworth, Daniel, Jiang, Ing-Guey, Griffin, Matt, Lowson, Nataliea, Molaverdikhani, Karan, Neilson, Hilding, Phillips, Caprice, Preibisch, Thomas, Sarkar, Subhajit, Stassun, Keivan G., Ward-Thompson, Derek, Wright, Duncan, Yang, Ming, Yeh, Li-Chin, Zhou, Ji-Lin, Archer, Richard, Mohan, Yoga Barrathwaj Raman, Joshua, Max, Tessenyi, Marcell, Tennyson, Jonathan, and Wilcock, Benjamin
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: With a focus on off-the-shelf components, Twinkle is the first in a series of cost competitive small satellites managed and financed by Blue Skies Space Ltd. The satellite is based on a high-heritage Airbus platform that will carry a 0.45 m telescope and a spectrometer which will provide simultaneous wavelength coverage from 0.5-4.5 $\rm{\mu m}$. The spacecraft prime is Airbus Stevenage while the telescope is being developed by Airbus Toulouse and the spectrometer by ABB Canada. Scheduled to begin scientific operations in 2025, Twinkle will sit in a thermally-stable, sun-synchronous, low-Earth orbit. The mission has a designed operation lifetime of at least seven years and, during the first three years of operation, will conduct two large-scale survey programmes: one focused on Solar System objects and the other dedicated to extrasolar targets. Here we present an overview of the architecture of the mission, refinements in the design approach, and some of the key science themes of the extrasolar survey., Comment: Presented at SPIE Astronomical Telescopes & Instrumentation 2022
Published: 2022
Full Text: View/download PDF

17. Spectra of some weighted composition operators on the ball

Author: Kaschner, Scott, Le, Trieu, Makdad, Chloe, Rempfer, Benjamin, Thompson, Derek, and Winters, DeJuan
Published: 2023
Full Text: View/download PDF

18. Effects of magnetic field orientations in dense cores on gas kinematics in protostellar envelopes

Author: Gupta, Aashish, Yen, Hsi-Wei, Koch, Patrick, Bastien, Pierre, Bourke, Tyler L., Chung, Eun Jung, Hasegawa, Tetsuo, Hull, Charles L. H., Inutsuka, Shu-ichiro, Kwon, Jungmi, Kwon, Woojin, Lai, Shih-Ping, Lee, Chang Won, Lee, Chin-Fei, Pattle, Kate, Qiu, Keping, Tahani, Mehrnoosh, Tamura, Motohide, and Ward-Thompson, Derek
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Theoretically, misalignment between the magnetic field and rotational axis in a dense core is considered to be dynamically important in the star formation process, however, extent of this influence remains observationally unclear. For a sample of 32 Class 0 and I protostars in the Perseus Molecular Cloud, we analyzed gas motions using C$^{18}$O data from the SMA MASSES survey and the magnetic field structures using 850 $\mu$m polarimetric data from the JCMT BISTRO-1 survey and archive. We do not find any significant correlation between the velocity gradients in the C$^{18}$O emission in the protostellar envelopes at a 1,000 au scale and the misalignment between the outflows and magnetic field orientations in the dense cores at a 4,000 au scale, and there is also no correlation between the velocity gradients and the angular dispersions of the magnetic fields. However, a significant dependence on the misalignment angles emerges after we normalize the rotational motion by the infalling motion, where the ratios increase from $\lesssim1$ to $\gtrsim1$ with increasing misalignment angles. This suggests that the misalignment could prompt angular momentum transportation to the envelope scale but is not a dominant factor in determining the envelope rotation, and other parameters, like mass accretion in protostellar sources, also play an important role. These results remain valid after taking into account projection effects. The comparison between our estimated angular momentum in the protostellar envelopes and the sizes of the known protostellar disks suggests that significant angular momentum is likely lost between radii of $\sim$1,000-100 au in protostellar envelopes., Comment: Accepted by ApJ
Published: 2022
Full Text: View/download PDF

19. Powers of posinormal Hilbert-space operators

Author: Bourdon, Paul S., Kubrusly, C. S., and Thompson, Derek
Subjects: Mathematics - Functional Analysis, 47B02, 47B20
Abstract: A bounded linear operator $A$ on a Hilbert space $\mathcal{H}$ is posinormal if there exists a positive operator $P$ such that $AA^{*} = A^{*}PA$. We show that if $A$ is posinormal with closed range, then $A^n$ is posinormal and has closed range for all integers $n\ge 1$. Because the collection of posinormal operators includes all hyponormal operators, we obtain as a corollary that powers of closed-range hyponormal operators continue to have closed range. We also present a simple example of a closed-range operator $T: \mathcal{H}\to \mathcal{H}$ such that $T^2$ does not have closed range., Comment: 4 pages. After posting v1, the authors discovered v1's Main Theorem is already in the literature, expressed in different language and having different ancestry. V2 provides details
Published: 2022

20. Posinormal Composition Operators on $H^2$

Author: Bourdon, Paul S. and Thompson, Derek
Subjects: Mathematics - Functional Analysis, 47B20, 47B33 (Primary) 47B35 (Secondary)
Abstract: A bounded linear operator $A$ on a Hilbert space is posinormal if there exists a positive operator $P$ such that $AA^{*} = A^{*}PA$. Posinormality of $A$ is equivalent to the inclusion of the range of $A$ in the range of its adjoint $A^*$. Every hyponormal operator is posinormal, as is every invertible operator. We characterize both the posinormal and coposinormal composition operators $C_\varphi$ on the Hardy space $H^2$ of the open unit disk $\mathbb{D}$ when $\varphi$ is a linear-fractional selfmap of $\mathbb{D}$. Our work reveals that there are composition operators that are both posinormal and coposinormal yet have powers that fail to be posinormal., Comment: 16 pages
Published: 2022

21. B-fields in Star-Forming Region Observations (BISTRO): Magnetic Fields in the Filamentary Structures of Serpens Main

Author: Kwon, Woojin, Pattle, Kate, Sadavoy, Sarah, Hull, Charles L. H., Johnstone, Doug, Ward-Thompson, Derek, Di Francesco, James, Koch, Patrick M., Furuya, Ray, Doi, Yasuo, Gouellec, Valentin J. M. Le, Hwang, Jihye, Lyo, A-Ran, Soam, Archana, Tang, Xindi, Hoang, Thiem, Kirchschlager, Florian, Eswaraiah, Chakali, Fanciullo, Lapo, Kim, Kyoung Hee, Onaka, Takashi, Könyves, Vera, Kang, Ji-hyun, Lee, Chang Won, Tamura, Motohide, Bastien, Pierre, Hasegawa, Tetsuo, Lai, Shih-Ping, Qiu, Keping, Berry, David, Arzoumanian, Doris, Bourke, Tyler L., Byun, Do-Young, Chen, Wen Ping, Chen, Huei-Ru Vivien, Chen, Mike, Chen, Zhiwei, Ching, Tao-Chung, Cho, Jungyeon, Choi, Yunhee, Choi, Minho, Chrysostomou, Antonio, Chung, Eun Jung, Coudé, Simon, Dai, Sophia, Diep, Pham Ngoc, Duan, Yan, Duan, Hao-Yuan, Eden, David, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Fuller, Gary, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hatchell, Jennifer, Hayashi, Saeko, Houde, Martin, Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Kang, Miju, Karoly, Janik, Kataoka, Akimasa, Kawabata, Koji, Kemper, Francisca, Kim, Kee-Tae, Kim, Gwanjeong, Kim, Mi-Ryang, Kim, Shinyoung, Kim, Jongsoo, Kirk, Jason, Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Law, Chi-Yan, Lee, Chin-Fei, Lee, Yong-Hee, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Sang-Sung, Li, Dalei, Li, Di, Li, Hua-bai, Lin, Sheng-Jun, Liu, Sheng-Yuan, Liu, Hong-Li, Liu, Junhao, Liu, Tie, Lu, Xing, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Ohashi, Nagayoshi, Park, Geumsook, Parsons, Harriet, Peretto, Nicolas, Priestley, Felix, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Jonathan, Rawlings, Mark G., Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Seta, Masumichi, Shimajiri, Yoshito, Shinnaga, Hiroko, Tahani, Mehrnoosh, Tang, Ya-Wen, Tomisaka, Kohji, Tram, Le Ngoc, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Wang, Jia-Wei, Whitworth, Anthony, Wu, Jintai, Xie, Jinjin, Yen, Hsi-Wei, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Yapeng, Zhang, Chuan-Peng, Zhang, Guoyin, Zhou, Jianjun, Zhu, Lei, de Looze, Ilse, André, Philippe, Dowell, C. Darren, Eyres, Stewart, Falle, Sam, Robitaille, Jean-François, and van Loo, Sven
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present 850 $\mu$m polarimetric observations toward the Serpens Main molecular cloud obtained using the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields In STar-forming Region Observations (BISTRO) survey. These observations probe the magnetic field morphology of the Serpens Main molecular cloud on about 6000 au scales, which consists of cores and six filaments with different physical properties such as density and star formation activity. Using the histogram of relative orientation (HRO) technique, we find that magnetic fields are parallel to filaments in less dense filamentary structures where $N_{H_2} < 0.93\times 10^{22}$ cm$^{-2}$ (magnetic fields perpendicular to density gradients), while being perpendicular to filaments (magnetic fields parallel to density gradients) in dense filamentary structures with star formation activity. Moreover, applying the HRO technique to denser core regions, we find that magnetic field orientations change to become perpendicular to density gradients again at $N_{H_2} \approx 4.6 \times 10^{22}$ cm$^{-2}$. This can be interpreted as a signature of core formation. At $N_{H_2} \approx 16 \times 10^{22}$ cm$^{-2}$ magnetic fields change back to being parallel to density gradients once again, which can be understood to be due to magnetic fields being dragged in by infalling material. In addition, we estimate the magnetic field strengths of the filaments ($B_{POS} = 60-300~\mu$G)) using the Davis-Chandrasekhar-Fermi method and discuss whether the filaments are gravitationally unstable based on magnetic field and turbulence energy densities., Comment: 18 pages, accepted for publication in ApJ
Published: 2022
Full Text: View/download PDF

22. The JCMT BISTRO Survey: Evidence for Pinched Magnetic Fields in Quiescent Filaments of NGC 1333

Author: Doi, Yasuo, Tomisaka, Kohji, Hasegawa, Tetsuo, Coudé, Simon, Arzoumanian, Doris, Bastien, Pierre, Matsumura, Masafumi, Tahani, Mehrnoosh, Sadavoy, Sarah, Hull, Charles L. H., Johnstone, Doug, Di Francesco, James, Shimajiri, Yoshito, Furuya, Ray S., Kwon, Jungmi, Tamura, Motohide, Ward-Thompson, Derek, Gouellec, Valentin J. M. Le, Hoang, Thiem, Kirchschlager, Florian, Hwang, Jihye, Eswaraiah, Chakali, Koch, Patrick M., Whitworth, Anthony P., Pattle, Kate, Kwon, Woojin, Kang, Jihyun, Inutsuka, Shu-ichiro, Bourke, Tyler L., Tang, Xindi, Fanciullo, Lapo, Lee, Chang Won, Liu, Hong-Li, Lyo, A-Ran, Qiu, Keping, and Lai, Shih-Ping
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We investigate the internal 3D magnetic structure of dense interstellar filaments within NGC 1333 using polarization data at $850 \mu\mathrm{m}$ from the $B$-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. Theoretical models predict that the magnetic field lines in a filament will tend to be dragged radially inward (i.e., pinched) toward the central axis due to the filament's self-gravity. We study the cross-sectional profiles of the total intensity ($I$) and polarized intensity (PI) of dust emission in four segments of filaments unaffected by local star formation that are expected to retain a pristine magnetic field structure. We find that the filaments' FWHM in PI are not the same as those in $I$, with two segments being appreciably narrower in PI (FWHM ratio $\simeq 0.7-0.8$) and one segment being wider (FWHM ratio $\simeq 1.3$). The filament profiles of the polarization fraction ($P$) do not show a minimum at the spine of the filament, which is not in line with an anticorrelation between $P$ and $I$ normally seen in molecular clouds and protostellar cores. Dust grain alignment variation with density cannot reproduce the observed $P$ distribution. We demonstrate numerically that the $I$ and PI cross-sectional profiles of filaments in magnetohydrostatic equilibrium will have differing relative widths depending on the viewing angle. The observed variations of FWHM ratios in NGC 1333 are therefore consistent with models of pinched magnetic field structures inside filaments, and especially if they are magnetically near-critical or supercritical., Comment: Accepted for publication in ApJL
Published: 2021
Full Text: View/download PDF

23. Spectra of Weighted Composition Operators with Quadratic Symbols

Author: Doctor, Jessica, Hodges, Timothy, Kaschner, Scott, McFarland, Alexander, and Thompson, Derek
Subjects: Mathematics - Functional Analysis, 47B33
Abstract: Previously, spectra of certain weighted composition operators on the Hardy Space were discovered under one of two hypotheses: either the compositional symbol converges under iteration to the Denjoy-Wolff point on all of the open disk rather than compact subsets, or the compositional symbol is "essentially linear fractional". We show that if the symbol is a quadratic self-map of the disk of parabolic type, then the spectrum of the weighted composition operators can be found when these maps exhibit both of the aforementioned properties, and most of them do.
Published: 2021

24. Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

Author: Janssen, Michael, Falcke, Heino, Kadler, Matthias, Ros, Eduardo, Wielgus, Maciek, Akiyama, Kazunori, Baloković, Mislav, Blackburn, Lindy, Bouman, Katherine L., Chael, Andrew, Chan, Chi-kwan, Chatterjee, Koushik, Davelaar, Jordy, Edwards, Philip G., Fromm, Christian M., Gómez, José L., Goddi, Ciriaco, Issaoun, Sara, Johnson, Michael D., Kim, Junhan, Koay, Jun Yi, Krichbaum, Thomas P., Liu, Jun, Liuzzo, Elisabetta, Markoff, Sera, Markowitz, Alex, Marrone, Daniel P., Mizuno, Yosuke, Müller, Cornelia, Ni, Chunchong, Pesce, Dominic W., Ramakrishnan, Venkatessh, Roelofs, Freek, Rygl, Kazi L. J., van Bemmel, Ilse, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Barrett, John, Benson, Bradford A., Bintley, Dan, Blundell, Raymond, Boland, Wilfred, Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Chesler, Paul M., Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph P., Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Fraga-Encinas, Raquel, Friberg, Per, Fuentes, Antonio, Galison, Peter, Gammie, Charles F., García, Roberto, Gelles, Zachary, Gentaz, Olivier, Georgiev, Boris, Gold, Roman, Gómez-Ruiz, Arturo I., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Hecht, Michael H., Hesper, Ronald, Himwich, Elizabeth, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jimenez-Rosales, Alejandra, Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kino, Motoki, Kofuji, Yutaro, Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Levis, Aviad, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Lindahl, Greg, Liu, Kuo, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Marscher, Alan P., Martí-Vidal, Iván, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Musoke, Gibwa, Mejías, Alejandro Mus, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Neilsen, Joey, Neri, Roberto, Noutsos, Aristeidis, Nowak, Michael A., Okino, Hiroki, Olivares, Héctor, Ortiz-León, Gisela N., Oyama, Tomoaki, Özel, Feryal, Palumbo, Daniel C. M., Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Piétu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Pötzl, Felix M., Prather, Ben, Preciado-López, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ricarte, Angelo, Ripperda, Bart, Rogers, Alan, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Sánchez, Salvador, Sánchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, André, Young, Ken, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guang-Yao, and Zhao, Shan-Shan
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimeter wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to $10-100$ gravitational radii ($r_g=GM/c^2$) scales in nearby sources. Centaurus A is the closest radio-loud source to Earth. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our galactic center. A large southern declination of $-43^{\circ}$ has however prevented VLBI imaging of Centaurus A below ${\lambda}1$cm thus far. Here, we show the millimeter VLBI image of the source, which we obtained with the Event Horizon Telescope at $228$GHz. Compared to previous observations, we image Centaurus A's jet at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly-collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that Centaurus A's source structure resembles the jet in Messier 87 on ${\sim}500r_g$ scales remarkably well. Furthermore, we identify the location of Centaurus A's SMBH with respect to its resolved jet core at ${\lambda}1.3$mm and conclude that the source's event horizon shadow should be visible at THz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses., Comment: 27 pages, 9 figures. This is a post-peer-review, pre-copyedit version of an article published in Nature Astronomy. The final authenticated version is available online at: https://doi.org/10.1038/s41550-021-01417-w
Published: 2021
Full Text: View/download PDF

25. The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale

Author: Satapathy, Kaushik, Psaltis, Dimitrios, Ozel, Feryal, Medeiros, Lia, Dougall, Sean T., Chan, Chi-kwan, Wielgus, Maciek, Prather, Ben S., Wong, George N., Gammie, Charles F., Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David R., Baloković, Mislav, Barrett, John, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope A., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Bustamente, Sandra, Byun, Do-Young, Carlstrom, John E., Chael, Andrew, Chatterjee, Koushik, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crawford, Thomas, Crew, Geoffrey B., Osorio, Alejandro Cruz, Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica T., Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph, Falcke, Heino, Farah, Joseph R., Fish, Vincent, Fomalont, Edward B., Ford, H. Alyson, Fraga-Encinas, Raquel, Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, García, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gomez-Ruiz, Arturo I., Gómez, Jose L., Gu, Minfeng, Gurwell, Mark A., Hada, Kazuhiro, Haggard, Daryl, Hecht, Michael, Hesper, Ronald, Ho, Luis C., Ho, Paul T., Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Rosales, Alejandra Jimenez, Johnson, Michael D., Jorstad, Svetlana G., Jung, Taehyun, Karami, Mr. Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Carsten, Kramer, Michael, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Levis, Aviad, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Lindahl, Greg, Liu, Jun, Liu, Kuo, Liuzzo, Miss Elisabetta, Lo, Wen-Ping, Lobanov, Andrei, Loinard, Laurent, Lonsdale, Colin J., Lu, Rusen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel, Marscher, Alan P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn, Menten, Karl M., Mizuno, Izumi, Mizuno, Yosuke, Moran, James, Moriyama, Kotaro, Moscibrodzka, Monika, Muller, Cornelia, Mejias, Alejandro M., Musoke, Gibwa, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Palumbo, Daniel C., Park, Jongho, Patel, Nimesh A., Pen, Ue-Li, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard L., PopStefanija, Aleksandar, Porth, Oliver, Potzl, Felix, Preciado-López, Jorge A., Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark, Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan E. E., Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Rygl, Kazi, Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhi-Qiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo, Titus, Michael, Toma, Kenji, Torne, Pablo, Traianou, E., Trent, Tyler, Trippe, Sascha, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Ward-Thompson, Derek, Wardle, John F., Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wiik, Kaj, Wu, Qingwen, Yoon, DooSoo, Young, Andre, Young, Ken H., Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guang-Yao, and Zhao, Shan-Shan
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5-61 days) is comparable to the 6-day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure phase measurements on all six linearly independent non-trivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of $\sim3-5^\circ$. The only triangles that exhibit substantially higher variability ($\sim90-180^\circ$) are the ones with baselines that cross visibility amplitude minima on the $u-v$ plane, as expected from theoretical modeling. We used two sets of General Relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black-hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black-hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas., Comment: Accepted for Publication in ApJ
Published: 2021
Full Text: View/download PDF

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

Author: Lyo, A-Ran, Kim, Jongsoo, Sadavoy, Sarah, Johnstone, Doug, Berry, David, Pattle, Kate, Kwon, Woojin, Bastien, Pierre, Onaka, Takashi, Di Francesco, James, Kang, Ji-Hyun, Furuya, Ray, Hull, Charles L. H., Tamura, Motohide, Koch, Patrick M., Ward-Thompson, Derek, Hasegawa, Tetsuo, Hoang, Thiem, Arzoumanian, Doris, Lee, Chang Won, Lee, Chin-Fei, Byun, Do-Young, Kirchschlager, Florian, Doi, Yasuo, Kim, Kee-Tae, Hwang, Jihye, Diep, Pham Ngoc, Fanciullo, Lapo, Lee, Sang-Sung, Park, Geumsook, Yoo, Hyunju, Chung, Eun Jung, Whitworth, Anthony, Mairs, Steve, Soam, Archana, Liu, Tie, Tang, Xindi, Coudé, Simon, André, Philippe, Bourke, Tyler L., Chen, Huei-Ru Vivien, Chen, Zhiwei, Chen, Wen Ping, Chen, Mike, Ching, Tao-Chung, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Chrysostomou, Antonio, Dai, Sophia, Dowell, C. Darren, Duan, Hao-Yuan, Duan, Yan, Eden, David, Eswaraiah, Chakali, Eyres, Stewart, Fiege, Jason, Fisse, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Fuller, Gary, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hatchell, Jannifer, Hayashi, Saeko, Houde, Martin, Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Kang, Miju, Kataoka, Akimasa, Kawabata, Koji, Kemper, Francisca, Kim, Gwanjeong, Kim, Mi-Ryang, Kim, Shinyoung, Kim, Kyoung Hee, Kirk, Jason, Kobayashi, Masato I. N., Könyves, Vera, Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Lai, Shih-Ping, Law, Chi-Yan, Lee, Jeong-Eun, Lee, Yong-Hee, Lee, Hyeseung, Li, Dalei, Li, Di, Li, Hua-Bai, Liu, Hong-Li, Liu, Junhao, Liu, Sheng-Yuan, Lu, Xing, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Ohashi, Nagayoshi, Parsons, Harriet, Peretto, Nicolas, Priestley, Felix, Pyo, Tae-soo, Qian, Lei, Qiu, Keping, Rao, Ramprasad, Rawlings, Jonathan, Rawlings, Mark G., Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Scaife, Anna, Seta, Masumichi, Shimajiri, Yoshito, Shinnaga, Hiroko, Tahani, Mehrnoosh, Tang, Ya-Wen, Tomisaka, Kohji, Tram, Le Ngoc, Tsukamoto, Yusuke, Viti, Serena, Wang, Jia-Wei, Wang, Hongchi, Xie, Jinjin, Yen, Hsi-Wei, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Guoyin, Zhang, Chuan-Peng, Zhang, Yapeng, Zhou, Jianjun, Zhu, Lei, and de Looze, Ilse
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the results of simultaneous 450 $\mu$m and 850 $\mu$m polarization observations toward the massive star forming region NGC 2071IR, a target of the BISTRO (B-fields in Star-Forming Region Observations) Survey, using the POL-2 polarimeter and SCUBA-2 camera mounted on the James Clerk Maxwell Telescope. We find a pinched magnetic field morphology in the central dense core region, which could be due to a rotating toroidal disk-like structure and a bipolar outflow originating from the central young stellar object, IRS 3. Using the modified Davis-Chandrasekhar-Fermi method, we obtain a plane-of-sky magnetic field strength of 563$\pm$421 $\mu$G in the central $\sim$0.12 pc region from 850 $\mu$m polarization data. The corresponding magnetic energy density of 2.04$\times$10$^{-8}$ erg cm$^{-3}$ is comparable to the turbulent and gravitational energy densities in the region. We find that the magnetic field direction is very well aligned with the whole of the IRS 3 bipolar outflow structure. We find that the median value of polarization fractions, 3.0 \%, at 450 $\mu$m in the central 3 arcminute region, which is larger than the median value of 1.2 \% at 850 $\mu$m. The trend could be due to the better alignment of warmer dust in the strong radiation environment. We also find that polarization fractions decrease with intensity at both wavelengths, with slopes, determined by fitting a Rician noise model, of $0.59 \pm 0.03$ at 450 $\mu$m and $0.36 \pm 0.04$ at 850 $\mu$m, respectively. We think that the shallow slope at 850 $\mu$m is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects., Comment: 17 pages, 11 figures, 4 tables
Published: 2021
Full Text: View/download PDF

27. Constraints on black-hole charges with the 2017 EHT observations of M87*

Author: Kocherlakota, Prashant, Rezzolla, Luciano, Falcke, Heino, Fromm, Christian M., Kramer, Michael, Mizuno, Yosuke, Nathanail, Antonios, Olivares, Hector, Younsi, Ziri, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chael, Andrew, Chan, Chi-kwan, Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Chesler, Paul M., Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Doeleman, Sheperd S., Eatough, Ralph P., Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Friberg, Per, Ford, H. Alyson, Fuentes, Antonio, Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gomez, Jose L., Gomez-Ruiz, Arturo I., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Jimenez-Rosales, Alejandra, Johnson, Michael D., Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Carsten, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Levis, Aviad, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Lindahl, Greg, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Muller, Cornelia, Musoke, Gibwa, Mejias, Alejandro Mus, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neilsen, Joseph, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Okino, Hiroki, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Ozel, Feryal, Palumbo, Daniel C. M., Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Potzl, Felix M., Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Ricarte, Angelo, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, Andre, Young, Ken, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guang-Yao, Zhao, Shan-Shan, and Collaboration, The EHT
Subjects: General Relativity and Quantum Cosmology
Abstract: Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M87* shadow size to infer constraints on the physical charges of a large variety of nonrotating or rotating black holes. For example, we show that the quality of the measurements is already sufficient to rule out that M87* is a highly charged dilaton black hole. Similarly, when considering black holes with two physical and independent charges, we are able to exclude considerable regions of the space of parameters for the doubly-charged dilaton and the Sen black holes., Comment: 15 pages, 4 figures, published in PRD on May 19
Published: 2021
Full Text: View/download PDF

28. The Polarized Image of a Synchrotron Emitting Ring of Gas Orbiting a Black Hole

Author: Narayan, Ramesh, Palumbo, Daniel C. M., Johnson, Michael D., Gelles, Zachary, Himwich, Elizabeth, Chang, Dominic O., Ricarte, Angelo, Dexter, Jason, Gammie, Charles F., Chael, Andrew A., Collaboration, The Event Horizon Telescope, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chan, Chi-kwan, Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Chesler, Paul M., Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, Davelaar, Jordy, DeLaurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Fraga-Encinas, Raquel, Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Garcıa, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gomez, Jose L., Gomez-Ruiz, Arturo I., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Jimenez-Rosales, Alejandra, Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Levis, Aviad, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Lindahl, Greg, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Pin, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Martı-Vidal, Alan P. Marscher Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Muller, Cornelia, Musoke, Gibwa, Mejıas, Alejandro Mus, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Ozel, Feryal, Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Potzl, Felix M., Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, Andre, Young, Ken, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guang-Yao, and Zhao, Shan-Shan
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov (2002) and conservation of the Walker-Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images., Comment: 29 pages, 11 figures, published in ApJ on May 3
Published: 2021
Full Text: View/download PDF

29. The JCMT BISTRO-2 Survey: The Magnetic Field in the Center of the Rosette Molecular Cloud

Author: Könyves, Vera, Ward-Thompson, Derek, Pattle, Kate, Di Francesco, James, Arzoumanian, Doris, Chen, Zhiwei, Diep, Pham Ngoc, Eswaraiah, Chakali, Fanciullo, Lapo, Furuya, Ray S., Hoang, Thiem, Hull, Charles L. H., Hwang, Jihye, Johnstone, Doug, Kang, Ji-hyun, Karoly, Janik, Kirchschlager, Florian, Kirk, Jason M., Koch, Patrick M., Kwon, Jungmi, Lee, Chang Won, Onaka, Takashi, Robitaille, Jean-François, Soam, Archana, Tahani, Mehrnoosh, Tang, Xindi, Tamura, Motohide, Berry, David, Bastien, Pierre, Ching, Tao-Chung, Coudé, Simon, Kwon, Woojin, Wang, Jia-Wei, Hasegawa, Tetsuo, Lai, Shih-Ping, and Qiu, Keping
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the first 850 $\mu$m polarization observations in the most active star-forming site of the Rosette Molecular Cloud (RMC, $d\sim$1.6 kpc) in the wall of the Rosette Nebula, imaged with the SCUBA-2/POL-2 instruments of the JCMT, as part of the B-Fields In Star-Forming Region Observations 2 (BISTRO-2) survey. From the POL-2 data we find that the polarization fraction decreases with the 850 $\mu$m continuum intensity with $\alpha$ = 0.49 $\pm$ 0.08 in the $p \propto I^{\rm -\alpha}$ relation, which suggests that some fraction of the dust grains remain aligned at high densities. The north of our 850 $\mu$m image reveals a "gemstone ring" morphology, which is a $\sim$1 pc-diameter ring-like structure with extended emission in the "head" to the south-west. We hypothesize that it might have been blown by feedback in its interior, while the B-field is parallel to its circumference in most places. In the south of our SCUBA-2 field the clumps are apparently connected with filaments which follow Infrared Dark Clouds (IRDCs). Here, the POL-2 magnetic field orientations appear bimodal with respect to the large-scale Planck field. The mass of our effective mapped area is $\sim$ 174 $M_\odot$ that we calculate from 850 $\mu$m flux densities. We compare our results with masses from large-scale emission-subtracted Herschel 250 $\mu$m data, and find agreement within 30%. We estimate the POS B-field strength in one typical subregion using the Davis-Chandrasekhar-Fermi (DCF) technique and find 80 $\pm$ 30 $\mu$G toward a clump and its outskirts. The estimated mass-to-flux ratio of $\lambda$ = 2.3 $\pm$ 1.0 suggests that the B-field is not sufficiently strong to prevent gravitational collapse in this subregion., Comment: 15 pages (12+3), 9 figures, 1 table. Accepted for publication in the Astrophysical Journal
Published: 2021
Full Text: View/download PDF

30. The JCMT BISTRO Survey: The Distribution of Magnetic Field Strengths towards the OMC-1 Region

Author: Hwang, Jihye, Kim, Jongsoo, Pattle, Kate, Kwon, Woojin, Sadavoy, Sarah, Koch, Patrick M., Hull, Charles L. H., Johnstone, Doug, Furuya, Ray S., Lee, Chang Won, Arzoumanian, Doris, Tahani, Mehrnoosh, Eswaraiah, Chakali, Liu, Tie, Kirchschlager, Florian, Kim, Kee-Tae, Tamura, Mothohide, Kwon, Jungmi, Lyo, A-Ran, Soam, Archana, Kang, Ji-hyun, Bourke, Tyler L., Matsumura, Masafumi, Mairs, Steve, Kim, Gwanjeong, Park, Geumsook, Nakamura, Fumitaka, Onaka, Takashi, Tang, Xindi, Liu, Hong-Li, Ward-Thompson, Derek, Li, Di, Hoang, Thiem, Hasegawa, Tetsuo, Qiu, Keping, Lai, Shih-Ping, and Bastien, Pierre
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Measurement of magnetic field strengths in a molecular cloud is essential for determining the criticality of magnetic support against gravitational collapse. In this paper, as part of the JCMT BISTRO survey, we suggest a new application of the Davis-Chandrasekhar-Fermi (DCF) method to estimate the distribution of magnetic field strengths in the OMC-1 region. We use observations of dust polarization emission at 450 $\mu$m and 850 $\mu$m, and C$^{18}$O (3-2) spectral line data obtained with the JCMT. We estimate the volume density, the velocity dispersion and the polarization angle dispersion in a box, 40$''$ $\times$ 40$''$ (5$\times$5 pixels), which moves over the OMC-1 region. By substituting three quantities in each box to the DCF method, we get magnetic field strengths over the OMC-1 region. We note that there are very large uncertainties in inferred field strengths, as discussed in detail in this paper. The field strengths vary from 0.8 to 26.4 mG and their mean value is about 6 mG. Additionally, we obtain maps of the mass-to-flux ratio in units of a critical value and the Alfv$\acute{e}$n mach number. The central parts of the BN-KL and South (S) clumps in the OMC-1 region are magnetically supercritical, so the magnetic field cannot support the clumps against gravitational collapse. However, the outer parts of the region are magnetically subcritical. The mean Alfv$\acute{e}$n mach number is about 0.4 over the region, which implies that the magnetic pressure exceeds the turbulent pressure in the OMC 1 region., Comment: 28 pages
Published: 2021
Full Text: View/download PDF

31. Revealing the diverse magnetic field morphologies in Taurus dense cores with sensitive sub-millimeter polarimetry

Author: Eswaraiah, Chakali, Li, Di, Furuya, Ray S., Hasegawa, Tetsuo, Ward-Thompson, Derek, Qiu, Keping, Ohashi, Nagayoshi, Pattle, Kate, Sadavoy, Sarah, Hull, Charles L. H., Berry, David, Doi, Yasuo, Ching, Tao-Chung, Lai, Shih-Ping, Wang, Jia-Wei, Koch, Patrick M., Kwon, Jungmi, Kwon, Woojin, Bastien, Pierre, Arzoumanian, Doris, Coudé, Simon, Soam, Archana, Fanciullo, Lapo, Yen, Hsi-Wei, Liu, Junhao, Hoang, Thiem, Chen, Wen Ping, Shimajiri, Yoshito, Liu, Tie, Chen, Zhiwei, Li, Hua-bai, Lyo, A-Ran, Hwang, Jihye, Johnstone, Doug, Rao, Ramprasad, Ngoc, Nguyen Bich, Diep, Pham Ngoc, Mairs, Steve, Parsons, Harriet, Tamura, Motohide, Tahani, Mehrnoosh, Chen, Huei-Ru Vivien, Nakamura, Fumitaka, Shinnaga, Hiroko, Tang, Ya-Wen, Cho, Jungyeon, Lee, Chang Won, Inutsuka, Shu-ichiro, Inoue, Tsuyoshi, Iwasaki, Kazunari, Qian, Lei, Xie, Jinjin, Li, Dalei, Liu, Hong-Li, Zhang, Chuan-Peng, Chen, Mike, Zhang, Guoyin, Zhu, Lei, Zhou, Jianjun, André, Philippe, Liu, Sheng-Yuan, Yuan, Jinghua, Lu, Xing, Peretto, Nicolas, Bourke, Tyler L., Byun, Do-Young, Dai, Sophia, Duan, Yan, Duan, Hao-Yuan, Eden, David, Matthews, Brenda, Fiege, Jason, Fissel, Laura M., Kim, Kee-Tae, Lee, Chin-Fei, Kim, Jongsoo, Pyo, Tae-Soo, Choi, Yunhee, Choi, Minho, Chrysostomou, Antonio, Chung, Eun Jung, Tram, Le Ngoc, Franzmann, Erica, Friberg, Per, Friesen, Rachel, Fuller, Gary, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hatchell, Jennifer, Hayashi, Saeko, Houde, Martin, Kawabata, Koji, Jeong, Il-Gyo, Kang, Ji-hyun, Kang, Sung-ju, Kang, Miju, Kataoka, Akimasa, Kemper, Francisca, Rawlings, Mark, Rawlings, Jonathan, Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Scaife, Anna, Seta, Masumichi, Kim, Gwanjeong, Kim, Kyoung Hee, Kim, Mi-Ryang, Kirchschlager, Florian, Kirk, Jason, Kobayashi, Masato I. N., Konyves, Vera, Kusune, Takayoshi, Lacaille, Kevin, Law, Chi-Yan, Lee, Sang-Sung, Lee, Yong-Hee, Matsumura, Masafumi, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakanishi, Hiroyuki, Onaka, Takashi, Park, Geumsook, Tang, Xindi, Tomisaka, Kohji, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Whitworth, Anthony, Yoo, Hyunju, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Yapeng, de Looze, Ilse, Dowell, C. Darren, Eyres, Stewart, Falle, Sam, Robitaille, Jean-François, and van Loo, Sven
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We have obtained sensitive dust continuum polarization observations at 850 $\mu$m in the B213 region of Taurus using POL-2 on SCUBA-2 at the James Clerk Maxwell Telescope (JCMT), as part of the BISTRO (B-fields in STar-forming Region Observations) survey. These observations allow us to probe magnetic field (B-field) at high spatial resolution ($\sim$2000 au or $\sim$0.01 pc at 140 pc) in two protostellar cores (K04166 and K04169) and one prestellar core (Miz-8b) that lie within the B213 filament. Using the Davis-Chandrasekhar-Fermi method, we estimate the B-field strengths in K04166, K04169, and Miz-8b to be 38$\pm$14 $\mu$G, 44$\pm$16 $\mu$G, and 12$\pm$5 $\mu$G, respectively. These cores show distinct mean B-field orientations. 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. 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 disordered B-field which show 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., Comment: 20 pages (10 are main), 5 figures (3 are main), and 3 tables (2 are main); Accepted for its publication in ApJL
Published: 2021
Full Text: View/download PDF

32. Observations of magnetic fields surrounding LkH$\alpha$ 101 taken by the BISTRO survey with JCMT-POL-2

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

33. JCMT POL-2 and BISTRO Survey observations of magnetic fields in the L1689 molecular cloud

Author: Pattle, Kate, Lai, Shih-Ping, Di Francesco, James, Sadavoy, Sarah, Ward-Thompson, Derek, Johnstone, Doug, Hoang, Thiem, Arzoumanian, Doris, Bastien, Pierre, Bourke, Tyler L., Coudé, Simon, Doi, Yasuo, Eswaraiah, Chakali, Fanciullo, Lapo, Furuya, Ray S., Hwang, Jihye, Hull, Charles L. H., Kang, Jihyun, Kim, Kee-Tae, Kirchschlager, Florian, Kwon, Jungmi, Kwon, Woojin, Lee, Chang Won, Liu, Tie, Redman, Matt, Soam, Archana, Tahani, Mehrnoosh, Tamura, Motohide, and Tang, Xindi
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present 850$\mu$m polarization observations of the L1689 molecular cloud, part of the nearby Ophiuchus molecular cloud complex, taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT). We observe three regions of L1689: the clump L1689N which houses the IRAS 16293-2422 protostellar system, the starless clump SMM-16, and the starless core L1689B. We use the Davis-Chandrasekhar-Fermi method to estimate plane-of-sky field strengths of $366\pm 55$ $\mu$G in L1689N, $284\pm 34$ $\mu$G in SMM-16, and $72\pm 33$ $\mu$G in L1689B, for our fiducial value of dust opacity. These values indicate that all three regions are likely to be magnetically trans-critical with sub-Alfv\'{e}nic turbulence. In all three regions, the inferred mean magnetic field direction is approximately perpendicular to the local filament direction identified in $Herschel$ Space Telescope observations. The core-scale field morphologies for L1689N and L1689B are consistent with the cloud-scale field morphology measured by the $Planck$ Space Observatory, suggesting that material can flow freely from large to small scales for these sources. Based on these magnetic field measurements, we posit that accretion from the cloud onto L1689N and L1689B may be magnetically regulated. However, in SMM-16, the clump-scale field is nearly perpendicular to the field seen on cloud scales by $Planck$, suggesting that it may be unable to efficiently accrete further material from its surroundings., Comment: 29 pages, 9 figures, 4 tables. Accepted for publication in the Astrophysical Journal
Published: 2020
Full Text: View/download PDF

34. The JCMT BISTRO survey: alignment between outflows and magnetic fields in dense cores/clumps

Author: Yen, Hsi-Wei, Koch, Patrick M., Hull, Charles L. H., Ward-Thompson, Derek, Bastien, Pierre, Hasegawa, Tetsuo, Kwon, Woojin, Lai, Shih-Ping, Qiu, Keping, Ching, Tao-Chung, Chung, Eun Jung, Coude, Simon, Di Francesco, James, Diep, Pham Ngoc, Doi, Yasuo, Eswaraiah, Chakali, Falle, Sam, Fuller, Gary, Furuya, Ray S., Han, Ilseung, Hatchell, Jennifer, Houde, Martin, Inutsuka, Shu-ichiro, Johnstone, Doug, Kang, Ji-hyun, Kang, Miju, Kim, Kee-Tae, Kirchschlager, Florian, Kwon, Jungmi, Lee, Chang Won, Lee, Chin-Fei, Liu, Hong-Li, Liu, Tie, Lyo, A-Ran, Ohashi, Nagayoshi, Onaka, Takashi, Pattle, Kate, Sadavoy, Sarah, Saito, Hiro, Shinnaga, Hiroko, Soam, Archana, Tahani, Mehrnoosh, Tamura, Motohide, Tang, Ya-Wen, Tang, Xindi, and Zhang, Chuan-Peng
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We compare the directions of molecular outflows of 62 low-mass Class 0 and I protostars in nearby (<450 pc) star-forming regions with the mean orientations of the magnetic fields on 0.05-0.5 pc scales in the dense cores/clumps where they are embedded. The magnetic field orientations were measured using the JCMT POL-2 data taken by the BISTRO-1 survey and from the archive. The outflow directions were observed with interferometers in the literature. The observed distribution of the angles between the outflows and the magnetic fields peaks between 15 and 35 degrees. After considering projection effects, our results could suggest that the outflows tend to be misaligned with the magnetic fields by 50+/-15 degrees in three-dimensional space and are less likely (but not ruled out) randomly oriented with respect to the magnetic fields. There is no correlation between the misalignment and the bolometric temperatures in our sample. In several sources, the small-scale (1000-3000 au) magnetic fields is more misaligned with the outflows than their large-scale magnetic fields, suggesting that the small-scale magnetic field has been twisted by the dynamics. In comparison with turbulent MHD simulations of core formation, our observational results are more consistent with models in which the energy densities in the magnetic field and the turbulence of the gas are comparable. Our results also suggest that the misalignment alone cannot sufficiently reduce the efficiency of magnetic braking to enable formation of the observed number of large Keplerian disks with sizes larger than 30-50 au., Comment: 27 pages, 14 figures, Accepted by ApJ
Published: 2020
Full Text: View/download PDF

35. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) II. Survey overview: a first look at 1.3 mm continuum maps and molecular outflows

Author: Dutta, Somnath, Lee, Chin-Fei, Liu, Tie, Hirano, Naomi, Liu, Sheng-Yuan, Tatematsu, Kenichi, Kim, Kee-Tae, Shang, Hsien, Sahu, Dipen, Kim, Gwanjeong, Moraghan, Anthony, Jhan, Kai-Syun, Hsu, Shih-Ying, Evans, Neal J., Johnstone, Doug, Ward-Thompson, Derek, Kuan, Yi-Jehng, Lee, Chang Won, Lee, Jeong-Eun, Traficante, Alessio, Juvela, Mika, Vastel, Charlotte, Zhang, Qizhou, Sanhueza, Patricio, Soam, Archana, Kwon, Woojin, Bronfman, Leonardo, Eden, David, Goldsmith, Paul F., He, Jinhua, Wu, Yuefang, Pelkonen, Veli-Matti, Qin, Sheng-Li, Li, Shanghuo, and Li, Di
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: Planck Galactic Cold Clumps (PGCCs) are contemplated to be the ideal targets to probe the early phases of star formation. We have conducted a survey of 72 young dense cores inside PGCCs in the Orion complex with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3\,mm (band 6) using three different configurations (resolutions $\sim$ 0$\farcs$35, 1$\farcs$0, and 7$\farcs$0) to statistically investigate their evolutionary stages and sub-structures. We have obtained images of the 1.3\,mm continuum and molecular line emission ($^{12}$CO, and SiO) at an angular resolution of $\sim$ 0$\farcs$35 ($\sim$ 140\,au) with the combined arrays. We find 70 substructures within 48 detected dense cores with median dust-mass $\sim$ 0.093\,M$_{\sun}$ and deconvolved size $\sim$ 0$\farcs$27. Dense substructures are clearly detected within the central 1000\,au of four candidate prestellar cores. The sizes and masses of the substructures in continuum emission are found to be significantly reduced with protostellar evolution from Class\,0 to Class\,I. We also study the evolutionary change in the outflow characteristics through the course of protostellar mass accretion. A total of 37 sources exhibit CO outflows, and 20 ($>$50\%) show high-velocity jets in SiO. The CO velocity-extents ($\Delta$Vs) span from 4 to 110 km/s with outflow cavity opening angle width at 400\,au ranging from $[\Theta_{obs}]_{400}$ $\sim$ 0$\farcs$6 to 3$\farcs$9, which corresponds to 33$\fdg$4$-$125$\fdg$7. For the majority of the outflow sources, the $\Delta$Vs show a positive correlation with $[\Theta_{obs}]_{400}$, suggesting that as protostars undergo gravitational collapse, the cavity opening of a protostellar outflow widens and the protostars possibly generate more energetic outflows., Comment: 43 pages, 25 figures (14 in the main text, 9 in the appendix), accepted for publication in the Astrophysical Journal Supplement Series (ApJS)
Published: 2020
Full Text: View/download PDF

36. Compressed magnetized shells of atomic gas and the formation of the Corona Australis molecular cloud

Author: Bracco, Andrea, Bresnahan, David, Palmeirim, Pedro, Arzoumanian, Doris, André, Philippe, Ward-Thompson, Derek, and Marchal, Antoine
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the identification of the previously unnoticed physical association between the Corona Australis molecular cloud (CrA), traced by interstellar dust emission, and two shell-like structures observed with line emission of atomic hydrogen (HI) at 21 cm. Although the existence of the two shells had already been reported in the literature, the physical link between the HI emission and CrA was never highlighted before. We use both Planck and Herschel data to trace dust emission and the Galactic All Sky HI Survey (GASS) to trace HI. The physical association between CrA and the shells is assessed based both on spectroscopic observations of molecular and atomic gas and on dust extinction data with Gaia. The shells are located at a distance between 140 and 190 pc, comparable to the distance of CrA, which we derive as 150.5 +- 6.3 pc. We also employ dust polarization observations from Planck to trace the magnetic-field structure of the shells. Both of them show patterns of magnetic-field lines following the edge of the shells consistently with the magnetic-field morphology of CrA. We estimate the magnetic-field strength at the intersection of the two shells via the Davis-Chandrasekhar-Fermi (DCF) method. Albeit the many caveats that are behind the DCF method, we find a magnetic-field strength of 27 +- 8 $\mu$G, at least a factor of two larger than the magnetic-field strength computed off of the HI shells. This value is also significantly larger compared to the typical values of a few $\mu$G found in the diffuse HI gas from Zeeman splitting. We interpret this as the result of magnetic-field compression caused by the shell expansion. This study supports a scenario of molecular-cloud formation triggered by supersonic compression of cold magnetized HI gas from expanding interstellar bubbles., Comment: 11 pages, 10 figures, Accepted for publication by A&A on October 20, 2020
Published: 2020
Full Text: View/download PDF

37. Herschel Gould Belt Survey Observations of Dense Cores in the Cepheus Flare Clouds

Author: Di Francesco, James, Keown, Jared, Fallscheer, Cassandra, André, Philippe, Ladjelate, Bilal, Könyves, Vera, Men'shchikov, Alexander, Stephens-Whale, Shaun, Nguyen-Luong, Quang, Martin, Peter, Sadavoy, Sarah, Pezzuto, Stefano, Fiorellino, Eleonora, Benedettini, Milena, Schneider, Nicola, Bontemps, Sylvain, Arzoumanian, Doris, Palmeirim, Pedro, Kirk, Jason M., and Ward-Thompson, Derek
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present Herschel SPIRE and PACS maps of the Cepheus Flare clouds L1157, L1172, L1228, L1241, and L1251, observed by the Herschel Gould Belt Survey (HGBS) of nearby star-forming molecular clouds. Through modified blackbody fits to the SPIRE and PACS data, we determine typical cloud column densities of 0.5-1.0 $\times$ 10$^{21}$ cm$^{-2}$ and typical cloud temperatures of 14-15 K. Using the getsources identification algorithm, we extract 832 dense cores from the SPIRE and PACS data at 160-500 $\mu$m. From placement in a mass vs. size diagram, we consider 303 to be candidate prestellar cores, and 178 of these to be "robust" prestellar cores. From an independent extraction of sources at 70 $\mu$m, we consider 25 of the 832 dense cores to be protostellar. The distribution of background column densities coincident with candidate prestellar cores peaks at 2-4 $\times$ 10$^{21}$ cm$^{-2}$. About half of the candidate prestellar cores in Cepheus may have formed due to the widespread fragmentation expected to occur within filaments of "transcritical" line mass. The lognormal robust prestellar core mass function (CMF) drawn from all five Cepheus clouds peaks at 0.56 M$_{\odot}$ and has a width of $\sim$0.5 dex, similar to that of Aquila's CMF. Indeed, the width of Cepheus' aggregate CMF is similar to the stellar system Initial Mass Function (IMF). The similarity of CMF widths in different clouds and the system IMF suggests a common, possibly turbulent origin for seeding the fluctuations that evolve into prestellar cores and stars., Comment: 36 pages, 21 figures, 2 online text tables (not yet included here), accepted for publication in The Astrophysical Journal
Published: 2020
Full Text: View/download PDF

38. Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole

Author: Psaltis, Dimitrios, Medeiros, Lia, Christian, Pierre, Ozel, Feryal, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Ball, David, Balokovic, Mislav, Barrett, John, Bintley, Dan, Blackburn, Lindy, Boland, Wilfred, Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chael, Andrew, Chan, Chi-kwan, Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Conway, John E., Cordes, James M., Crew, Geoffrey B., Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Eatough, Ralph P., Falcke, Heino, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Friberg, Per, Fromm, Christian M., Gammie, Charles F., García, Roberto, Gentaz, Olivier, Goddi, Ciriaco, Gomez, Jose L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jiang, Wu, Jimenez-Rosales, Alejandra, Johnson, Michael D., Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Jae-Young, Kim, Junhan, Kim, Jongsoo, Kino, Motoki, Koay, Jun Yi, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Lonsdale, Colin, Lu, Ru-Sen, Mao, Jirong, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Ivan, Matsushita, Satoki, Mizuno, Yosuke, Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Muller, Cornelia, Musoke, Gibwa, Mejías, Alejandro Mus, Nagai, Hiroshi, Nagar, Neil M., Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neri, Roberto, Noutsos, Aristeidis, Okino, Hiroki, Olivares, Hector, Oyama, Tomoaki, Palumbo, Daniel C. M., Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Prather, Ben, Preciado-Lopez, Jorge A., Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Ryan, Benjamin R., Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Tazaki, Fumie, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Wardle, John, Ward-Thompson, Derek, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, Andre, Young, Ken, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zhao, Shan-Shan, and Collaboration, the EHT
Subjects: General Relativity and Quantum Cosmology, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. We use numerical calculations of regular, parametric, non-Kerr metrics to identify the common characteristic among these different parametrizations that control the predicted shadow size. We show that the shadow-size measurements place significant constraints on deviation parameters that control the second post-Newtonian and higher orders of each metric and are, therefore, inaccessible to weak-field tests. The new constraints are complementary to those imposed by observations of gravitational waves from stellar-mass sources., Comment: Physical Review Letters
Published: 2020
Full Text: View/download PDF

39. OMC-1 dust polarisation in ALMA Band 7: Diagnosing grain alignment mechanisms in the vicinity of Orion Source I

Author: Pattle, Kate, Lai, Shih-Ping, Wright, Melvyn, Coudé, Simon, Plambeck, Richard, Hoang, Thiem, Tang, Ya-Wen, Bastien, Pierre, Eswaraiah, Chakali, Furuya, Ray, Hwang, Jihye, Inutsuka, Shu-ichiro, Kim, Kee-Tae, Kirchschlager, Florian, Kwon, Woojin, Lee, Chang Won, Liu, Sheng-Yuan, Lyo, Aran, Ohashi, Nagayoshi, Rawlings, Mark, Tahani, Mehrnoosh, Tamura, Motohide, Soam, Archana, Wang, Jia-Wei, and Ward-Thompson, Derek
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present ALMA Band 7 polarisation observations of the OMC-1 region of the Orion molecular cloud. We find that the polarisation pattern observed in the region is likely to have been significantly altered by the radiation field of the $>10^{4}$ L$_{\odot}$ high-mass protostar Orion Source I. In the protostar's optically thick disc, polarisation is likely to arise from dust self-scattering. In material to the south of Source I - previously identified as a region of 'anomalous' polarisation emission - we observe a polarisation geometry concentric around Source I. We demonstrate that Source I's extreme luminosity may be sufficient to make the radiative precession timescale shorter than the Larmor timescale for moderately large grains ($> 0.005-0.1\,\mu$m), causing them to precess around the radiation anisotropy vector (k-RATs) rather than the magnetic field direction (B-RATs). This requires relatively unobscured emission from Source I, supporting the hypothesis that emission in this region arises from the cavity wall of the Source I outflow. This is one of the first times that evidence for k-RAT alignment has been found outside of a protostellar disc or AGB star envelope. Alternatively, the grains may remain aligned by B-RATs and trace gas infall onto the Main Ridge. Elsewhere, we largely find the magnetic field geometry to be radial around the BN/KL explosion centre, consistent with previous observations. However, in the Main Ridge, the magnetic field geometry appears to remain consistent with the larger-scale magnetic field, perhaps indicative of the ability of the dense Ridge to resist disruption by the BN/KL explosion., Comment: 20 pages, 20 figures, 3 tables, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
Published: 2020
Full Text: View/download PDF

40. HAWC+ Far-Infrared Observations of the Magnetic Field Geometry in M51 and NGC 891

Author: Jones, Terry Jay, Kim, Jin-Ah, Dowell, C. Darren, Morris, Mark R., Pineda, Jorge L., Benford, Dominic J., Berthoud, Marc, Chuss, David T., Dale, Daniel A., Fissel, L. M., Goldsmith, Paul F., Hamilton, Ryan T., Hanany, Shaul, Harper, Doyal A., Henning, Thomas K., Lazarian, Alex, Looney, Leslie W., Michail, Joseph M., Novak, Giles, Santos, Fabio P., Sheth, Kartik, Siah, Javad, Stacey, Gordon J., Staguhn, Johannes, Stephens, Ian W., Tassis, Konstantinos, Trinh, Christopher Q., Vaillancourt, John E., Ward-Thompson, Derek, Werner, Michael, Wollack, Edward J., and Zweibel, Ellen G.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: SOFIA HAWC+ polarimetry at $154~\micron$ is reported for the face-on galaxy M51 and the edge-on galaxy NGC 891. For M51, the polarization vectors generally follow the spiral pattern defined by the molecular gas distribution, the far-infrared (FIR) intensity contours, and other tracers of star formation. The fractional polarization is much lower in the FIR-bright central regions than in the outer regions, and we rule out loss of grain alignment and variations in magnetic field strength as causes. When compared with existing synchrotron observations, which sample different regions with different weighting, we find the net position angles are strongly correlated, the fractional polarizations are moderately correlated, but the polarized intensities are uncorrelated. We argue that the low fractional polarization in the central regions must be due to significant numbers of highly turbulent segments across the beam and along lines of sight in the beam in the central 3 kpc of M51. For NGC 891, the FIR polarization vectors within an intensity contour of 1500 $\rm{MJy~sr^{-1}}$ are oriented very close to the plane of the galaxy. The FIR polarimetry is probably sampling the magnetic field geometry in NGC 891 much deeper into the disk than is possible with NIR polarimetry and radio synchrotron measurements. In some locations in NGC 891 the FIR polarization is very low, suggesting we are preferentially viewing the magnetic field mostly along the line of sight, down the length of embedded spiral arms. There is tentative evidence for a vertical field in the polarized emission off the plane of the disk., Comment: AJ, Accepted, In Press
Published: 2020
Full Text: View/download PDF

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

Author: Doi, Yasuo, Hasegawa, Tetsuo, Furuya, Ray S., Coudé, Simon, Hull, Charles L. H., Arzoumanian, Doris, Bastien, Pierre, Chen, Michael Chun-Yuan, di Francesco, James, Friesen, Rachel, Houde, Martin, Inutsuka, Shu-ichiro, Mairs, Steve, Matsumura, Masafumi, Onaka, Takashi, Sadavoy, Sarah, Shimajiri, Yoshito, Tahani, Mehrnoosh, Tomisaka, Kohji, Eswaraiah, Chakali, Koch, Patrick M., Pattle, Kate, Lee, Chang Won, Tamura, Motohide, Berry, David, Ching, Tao-Chung, Hwang, Jihye, Kwon, Woojin, Soam, Archana, Wang, Jia-Wei, Lai, Shih-Ping, Qiu, Keping, Ward-Thompson, Derek, Byun, Do-Young, Chen, Huei-Ru V., Chen, Wen Ping, Chen, Zhiwei, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Chrysostomou, Antonio, Chung, Eun Jung, Diep, Pham Ngoc, Duan, Hao-Yuan, Fanciullo, Lapo, Fiege, Jason, Franzmann, Erica, Friberg, Per, Fuller, Gary, Gledhill, Tim, Graves, Sarah F., Greaves, Jane S., Griffin, Matt J., Gu, Qilao, Han, Ilseung, Hatchell, Jennifer, Hayashi, Saeko S., Hoang, Thiem, Inoue, Tsuyoshi, Iwasaki, Kazunari, Jeong, Il-Gyo, Johnstone, Doug, Kanamori, Yoshihiro, Kang, Ji-hyun, Kang, Miju, Kang, Sung-Ju, Kataoka, Akimasa, Kawabata, Koji S., Kemper, Francisca, Kim, Gwanjeong, Kim, Jongsoo, Kim, Kee-Tae, Kim, Kyoung Hee, Kim, Mi-Ryang, Kim, Shinyoung, Kirk, Jason M., Kobayashi, Masato I. N., Konyves, Vera, Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Law, Chi-Yan, Lee, Chin-Fei, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Sang-Sung, Lee, Yong-Hee, Li, Dalei, Li, Di, Li, Hua-Bai, Liu, Hong-Li, Liu, Junhao, Liu, Sheng-Yuan, Liu, Tie, de Looze, Ilse, Lyo, A-Ran, Matthews, Brenda C., Moriarty-Schieven, Gerald H., Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ohashi, Nagayoshi, Park, Geumsook, Parsons, Harriet, Peretto, Nicolas, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Mark G., Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Scaife, Anna M. M., Seta, Masumichi, Shinnaga, Hiroko, Tang, Ya-Wen, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Whitworth, Anthony P., Yen, Hsi-Wei, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Chuan-Peng, Zhang, Guoyin, Zhang, Yapeng, Zhou, Jianjun, Zhu, Lei, André, Philippe, Dowell, C. Darren, Eyres, Stewart P. S., Falle, Sam, van Loo, Sven, and Robitaille, Jean-François
Subjects: Astrophysics - Astrophysics of Galaxies
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 x 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., Comment: 33 pages, 21 figures, accepted for publication in ApJ
Published: 2020
Full Text: View/download PDF

42. The Herschel view of the dense core population in the Ophiuchus molecular cloud

Author: Ladjelate, Bilal, André, Philippe, Könyves, Vera, Ward-Thompson, Derek, Men'shchikov, Alexander, Bracco, Andrea, Palmeirim, Pedro, Roy, Arabindo, Shimajiri, Yoshito, Kirk, Jason M., Arzoumanian, Doris, Benedettini, Milena, Di Francesco, James, Fiorellino, Eleonora, Schneider, Nicola, and Pezzuto, Stefano
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: Herschel observations of nearby clouds in the Gould Belt support a paradigm for low-mass star formation, starting with the generation of molecular filaments, followed by filament fragmentation, and the concentration of mass into self-gravitating prestellar cores. With the unique far-infrared and submillimeter continuum imaging capabilities of the Herschel Space observatory, the closeby (d = 139 pc) Ophiuchus cloud was mapped at five wavelengths from 70 ${\mu}m$ to 500 ${\mu}m$ with the aim of providing a complete census of dense cores in this region, including unbound starless cores, bound prestellar cores, and protostellar cores. Taking advantage of the high dynamic range and multi-wavelength nature of the Herschel data, we used the multi-scale decomposition algorithms getsources and getfilaments to identify a complete sample of dense cores and filaments in the cloud and study their properties. The densest clouds of the Ophiuchus complex, L1688 and L1689, which thus far are only indirectly described as filamentary regions owing to the spatial distribution of their young stellar objects (YSOs), are confirmed to be dominated by filamentary structures. The tight correlation observed between prestellar cores and filamentary structures in L1688 and L1689 supports the view that solar-type star formation occurs primarily in dense filaments. While the sub clouds of the complex show disparities, L1689 being less efficient than L1688 at forming stars when considering their total mass budgets, both sub clouds share almost the same prestellar core formation efficiency in dense molecular gas. We also find evidence in the Herschel data for a remarkable concentric geometrical configuration in L1688 which is dominated by up to three arc-like compression fronts and presumably created by shockwave events emanating from the Sco OB2 association, including the neighboring massive (O9V) star ${\sigma}$ Sco., Comment: Accepted for publication in A&A
Published: 2020
Full Text: View/download PDF

43. Unveiling the importance of magnetic fields in the evolution of dense clumps formed at the waist of bipolar H II regions: a case study on Sh2-201 with JCMT SCUBA-2/POL-2

Author: Eswaraiah, Chakali, Li, Di, Samal, Manash R., Wang, Jia-Wei, Ma, Yuehui, Lai, Shih-Ping, Zavagno, Annie, Ching, Tao-Chung, Liu, Tie, Pattle, Kate, Ward-Thompson, Derek, Pandey, Anil K., and Ojha, Devendra K.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the properties of magnetic fields (B-fields) in two clumps (clump 1 and clump 2), located at the waist of the bipolar H II region Sh2-201, based on JCMT SCUBA-2/POL-2 observations of 850 $\mu$m polarized dust emission. We find that B-fields in the direction of the clumps are bent and compressed, showing bow-like morphologies, which we attribute to the feedback effect of the H II region on the surface of the clumps. Using the modified Davis-Chandrasekhar-Fermi method we estimate B-fields strengths of 266 $\mu$G and 65 $\mu$G for clump 1 and clump 2, respectively. From virial analyses and critical mass ratio estimates, we argue that clump 1 is gravitationally bound and could be undergoing collapse, whereas clump 2 is unbound and stable. We hypothesize that the interplay between thermal pressure imparted by the H II region, B-field morphologies, and the various internal pressures of the clumps (such as magnetic, turbulent, and gas thermal pressure), has the following consequences: (a) formation of clumps at the waist of the H II region; (b) progressive compression and enhancement of the B-fields in the clumps; (c) stronger B-fields will shield the clumps from erosion by the H II region and cause pressure equilibrium between the clumps and the H II region, thereby allowing expanding I-fronts to blow away from the filament ridge, forming bipolar H II regions; and (d) stronger B-fields and turbulence will be able to stabilize the clumps. A study of a larger sample of bipolar H II regions would help to determine whether our hypotheses are widely applicable., Comment: 25 pages, 10 figures, and 4 tables. Accepted for publication in ApJ
Published: 2019
Full Text: View/download PDF

44. Star Formation in the Milky Way and Beyond in the Era of JWST and ALMA

Author: Pattle, Kate, primary and Ward-Thompson, Derek, additional
Published: 2024
Full Text: View/download PDF

45. Closed-range posinormal operators and their products

Author: Bourdon, Paul, Kubrusly, Carlos, Le, Trieu, and Thompson, Derek
Published: 2023
Full Text: View/download PDF

46. JCMT BISTRO Survey observations of the Ophiuchus Molecular Cloud: Dust grain alignment properties inferred using a Ricean noise model

Author: Pattle, Kate, Lai, Shih-Ping, Hasegawa, Tetsuo, Wang, Jia-Wei, Furuya, Ray, Ward-Thompson, Derek, Bastien, Pierre, Coudé, Simon, Eswaraiah, Chakali, Fanciullo, Lapo, di Francesco, James, Hoang, Thiem, Kim, Gwanjeong, Kwon, Woojin, Lee, Chang Won, Liu, Sheng-Yuan, Liu, Tie, Matsumura, Masafumi, Onaka, Takashi, Sadavoy, Sarah, and Soam, Archana
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The dependence of polarization fraction $p$ on total intensity $I$ in polarized submillimeter emission measurements is typically parameterized as $p\propto I^{-\alpha}$ $(\alpha \leq 1)$, and used to infer dust grain alignment efficiency in star-forming regions, with an index $\alpha=1$ indicating near-total lack of alignment of grains with the magnetic field. In this work we demonstrate that the non-Gaussian noise characteristics of polarization fraction may produce apparent measurements of $\alpha \sim 1$ even in data with significant signal-to-noise in Stokes $Q$, $U$ and $I$ emission, and so with robust measurements of polarization angle. We present a simple model demonstrating this behavior, and propose a criterion by which well-characterized measurements of polarization fraction may be identified. We demonstrate that where our model is applicable, $\alpha$ can be recovered by fitting the $p-I$ relationship with the mean of the Rice distribution, without statistical debiasing of polarization fraction. We apply our model to JCMT BISTRO Survey POL-2 850$\mu$m observations of three clumps in the Ophiuchus Molecular Cloud, finding that in the externally-illuminated Oph A region, $\alpha\approx 0.34$, while in the more isolated Oph B and C, despite their differing star formation histories, $\alpha \sim 0.6-0.7$. Our results thus suggest that dust grain alignment in dense gas is more strongly influenced by incident interstellar radiation field than by star formation history. We further find that grains may remain aligned with the magnetic field at significantly higher gas densities than has previously been believed, thus allowing investigation of magnetic field properties within star-forming clumps and cores., Comment: 21 pages, 8 figures, 3 tables, accepted for publication in ApJ
Published: 2019
Full Text: View/download PDF

47. The far-infrared polarization spectrum of Rho Ophiuchi A from HAWC+/SOFIA observations

Author: Santos, Fabio P., Chuss, David T., Dowell, C. Darren, Houde, Martin, Looney, Leslie W., Rodriguez, Enrique Lopez, Novak, Giles, Ward-Thompson, Derek, Berthoud, Marc, Dale, Daniel A., Guerra, Jordan A., Hamilton, Ryan T., Hanany, Shaul, Harper, Doyal A., Henning, Thomas K., Jones, Terry Jay, Lazarian, Alex, Michail, Joseph M., Morris, Mark R., Staguhn, Johannes, Stephens, Ian W., Tassis, Konstantinos, Trinh, Christopher Q., Van Camp, Eric, Volpert, C. G., and Wollack, Edward J.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We report on polarimetric maps made with HAWC+/SOFIA toward Rho Oph A, the densest portion of the Rho Ophiuchi molecular complex. We employed HAWC+ bands C (89 $\mu$m) and D (154 $\mu$m). The slope of the polarization spectrum was investigated by defining the quantity R_DC = p_D/p_C, where p_C and p_D represent polarization degrees in bands C and D, respectively. We find a clear correlation between R_DC and the molecular hydrogen column density across the cloud. A positive slope (R_DC > 1) dominates the lower density and well illuminated portions of the cloud, that are heated by the high mass star Oph S1, whereas a transition to a negative slope (R_DC < 1) is observed toward the denser and less evenly illuminated cloud core. We interpret the trends as due to a combination of: (1) Warm grains at the cloud outskirts, which are efficiently aligned by the abundant exposure to radiation from Oph S1, as proposed in the radiative torques theory; and (2) Cold grains deep in the cloud core, which are poorly aligned due to shielding from external radiation. To assess this interpretation, we developed a very simple toy model using a spherically symmetric cloud core based on Herschel data, and verified that the predicted variation of R_DC is consistent with the observations. This result introduces a new method that can be used to probe the grain alignment efficiency in molecular clouds, based on the analysis of trends in the far-infrared polarization spectrum., Comment: Accepted by ApJ (July 18 2019)
Published: 2019
Full Text: View/download PDF

48. Revealing the Two `Horns' of Taurus with GAIA DR2

Author: Fleming, Graham D., Kirk, Jason Matthew, Ward-Thompson, Derek, and Pattle, Kate
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We investigate the spatial properties of sources from the GAIA catalogue previously identified as being members of the Taurus star forming region and which appear in the Spitzer catalogue. We study an area of sky of 10x15 deg, centred on Right Ascension (2000.0) = 68.5 deg and Declination (2000.0)= 27.0 deg, this being an area surrounding the Taurus molecular cloud. We use data obtained from the GAIA DR2 release. By using an inversion of GAIA parallax measurements to obtain distance values and by defining limits to the proper motions of the Taurus moving group, we are able to show that there are substantial differences in depth within the Taurus complex. Our results suggest that the Taurus cloud has significant depth and that there are two main associations centred at ~130.6+/-0.7 pc and ~160.2+/-0.9 pc at 1{\sigma}. These two associations also have different proper motions, of 24.5+/-2.8 and 20.1+/-2.4 mas/yr respectively. We here label them the 'Two Horns' of Taurus., Comment: 8 figures, 3 tables, 18 pages in preprint format, submitted to ApJ as manuscript AAS22430 on 18-Jan-2020
Published: 2019

49. The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-Forming Region

Author: Coudé, Simon, Bastien, Pierre, Houde, Martin, Sadavoy, Sarah, Friesen, Rachel, Di Francesco, James, Johnstone, Doug, Mairs, Steve, Hasegawa, Tetsuo, Kwon, Woojin, Lai, Shih-Ping, Qiu, Keping, Ward-Thompson, Derek, Berry, David, Chen, Michael Chun-Yuan, Fiege, Jason, Franzmann, Erica, Hatchell, Jennifer, Lacaille, Kevin, Matthews, Brenda C., Moriarty-Schieven, Gerald H., Pon, Andy, André, Philippe, Arzoumanian, Doris, Aso, Yusuke, Byun, Do-Young, Chakali, Eswaraiah, Chen, Huei-Ru, Chen, Wen Ping, Ching, Tao-Chung, Cho, Jungyeon, Choi, Minho, Chrysostomou, Antonio, Chung, Eun Jung, Doi, Yasuo, Drabek-Maunder, Emily, Dowell, C. Darren, Eyres, Stewart P. S., Falle, Sam, Friberg, Per, Fuller, Gary, Furuya, Ray S., Gledhill, Tim, Graves, Sarah F., Greaves, Jane S., Griffin, Matt J., Gu, Qilao, Hayashi, Saeko S., Hoang, Thiem, Holland, Wayne, Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Kanamori, Yoshihiro, Kataoka, Akimasa, Kang, Ji-hyun, Kang, Miju, Kang, Sung-ju, Kawabata, Koji S., Kemper, Francisca, Kim, Gwanjeong, Kim, Jongsoo, Kim, Kee-Tae, Kim, Kyoung Hee, Kim, Mi-Ryang, Kim, Shinyoung, Kirk, Jason M., Kobayashi, Masato I. N., Koch, Patrick M., Kwon, Jungmi, Lee, Jeong-Eun, Lee, Chang Won, Lee, Sang-Sung, Li, Dalei, Li, Di, Li, Hua-bai, Liu, Hong-Li, Liu, Junhao, Liu, Sheng-Yuan, Liu, Tie, van Loo, Sven, Lyo, A-Ran, Matsumura, Masafumi, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ohashi, Nagayoshi, Onaka, Takashi, Parsons, Harriet, Pattle, Kate, Peretto, Nicolas, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Mark G., Retter, Brendan, Richer, John, Rigby, Andrew, Robitaille, Jean-François, Saito, Hiro, Savini, Giorgio, Scaife, Anna M. M., Seta, Masumichi, Shinnaga, Hiroko, Soam, Archana, Tamura, Motohide, Tang, Ya-Wen, Tomisaka, Kohji, Tsukamoto, Yusuke, Wang, Hongchi, Wang, Jia-Wei, Whitworth, Anthony P., Yen, Hsi-Wei, Yoo, Hyunju, Yuan, Jinghua, Zenko, Tetsuya, Zhang, Chuan-Peng, Zhang, Guoyin, Zhou, Jianjun, and Zhu, Lei
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the POL-2 850 $\mu$m linear polarization map of the Barnard 1 clump in the Perseus molecular cloud complex from the B-fields In STar-forming Region Observations (BISTRO) survey at the James Clerk Maxwell Telescope. We find a trend of decreasing polarization fraction as a function of total intensity, which we link to depolarization effects towards higher density regions of the cloud. We then use the polarization data at 850 $\mu$m to infer the plane-of-sky orientation of the large-scale magnetic field in Barnard 1. This magnetic field runs North-South across most of the cloud, with the exception of B1-c where it turns more East-West. From the dispersion of polarization angles, we calculate a turbulence correlation length of $5.0 \pm 2.5$ arcsec ($1500$ au), and a turbulent-to-total magnetic energy ratio of $0.5 \pm 0.3$ inside the cloud. We combine this turbulent-to-total magnetic energy ratio with observations of NH$_3$ molecular lines from the Green Bank Ammonia Survey (GAS) to estimate the strength of the plane-of-sky component of the magnetic field through the Davis-Chandrasekhar-Fermi method. With a plane-of-sky amplitude of $120 \pm 60$ $\mu$G and a criticality criterion $\lambda_c = 3.0 \pm 1.5$, we find that Barnard 1 is a supercritical molecular cloud with a magnetic field nearly dominated by its turbulent component., Comment: 22 pages, 7 figures, accepted in the Astrophysical Journal
Published: 2019
Full Text: View/download PDF

50. The JCMT BISTRO Survey: The Magnetic Field In The Starless Core $\rho$ Ophiuchus C

Author: Liu, Junhao, Qiu, Keping, Berry, David, Di Francesco, James, Bastien, Pierre, Koch, Patrick M., Furuya, Ray S., Kim, Kee-Tae, Coudé, Simon, Lee, Chang Won, Soam, Archana, Eswaraiah, Chakali, Li, Di, Hwang, Jihye, Lyo, A-Ran, Pattle, Kate, Hasegawa, Tetsuo, Kwon, Woojin, Lai, Shih-Ping, Ward-Thompson, Derek, Ching, Tao-Chung, Chen, Zhiwei, Gu, Qilao, Li, Dalei, Li, Hua-bai, Liu, Hong-Li, Qian, Lei, Wang, Hongchi, Yuan, Jinghua, Zhang, Chuan-Peng, Zhang, Guoyin, Zhang, Ya-Peng, Zhou, Jianjun, Zhu, Lei, André, Philippe, Arzoumanian, Doris, Aso, Yusuke, Byun, Do-Young, Chen, Michael Chun-Yuan, Chen, Huei-Ru Vivien, Chen, Wen Ping, Cho, Jungyeon, Choi, Minho, Chrysostomou, Antonio, Chung, Eun Jung, Doi, Yasuo, Drabek-Maunder, Emily, Dowell, C. Darren, Eyres, Stewart P. S., Falle, Sam, Fanciullo, Lapo, Fiege, Jason, Franzmann, Erica, Friberg, Per, Friesen, Rachel K., Fuller, Gary, Gledhill, Tim, Graves, Sarah F., Greaves, Jane S., Griffin, Matt J., Han, Ilseung, Hatchell, Jennifer, Hayashi, Saeko S., Hoang, Thiem, Holland, Wayne, Houde, Martin, Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Johnstone, Doug, Kanamori, Yoshihiro, Kang, Ji-hyun, Kang, Miju, Kang, Sung-ju, Kataoka, Akimasa, Kawabata, Koji S., Kemper, Francisca, Kim, Gwanjeong, Kim, Jongsoo, Kim, Kyoung Hee, Kim, Mi-Ryang, Kim, Shinyoung, Kirk, Jason M., Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin M., Lee, Chin-Fei, Lee, Jeong-Eun, Lee, Hyeseung, Lee, Sang-Sung, Liu, Sheng-Yuan, Liu, Tie, van Loo, Sven, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda C., Moriarty-Schieven, Gerald H., Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ohashi, Nagayoshi, Onaka, Takashi, Parker, Josh, Parsons, Harriet, Pascale, Enzo, Peretto, Nicolas, Pon, Andy, Pyo, Tae-Soo, Rao, Ramprasad, Rawlings, Mark G., Retter, Brendan, Richer, John, Rigby, Andrew, Robitaille, Jean-François, Sadavoy, Sarah, Saito, Hiro, Savini, Giorgio, Scaife, Anna M. M., Seta, Masumichi, Shinnaga, Hiroko, Tamura, Motohide, Tang, Ya-Wen, Tomisaka, Kohji, Tsukamoto, Yusuke, Wang, Jia-Wei, Whitworth, Anthony P., Yen, Hsi-Wei, Yoo, Hyunju, and Zenko, Tetsuya
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We report 850~$\mu$m dust polarization observations of a low-mass ($\sim$12 $M_{\odot}$) starless core in the $\rho$ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields In STar-forming Region Observations (BISTRO) survey. We detect an ordered magnetic field projected on the plane of sky in the starless core. The magnetic field across the $\sim$0.1~pc core shows a predominant northeast-southwest orientation centering between $\sim$40$^\circ$ to $\sim$100$^\circ$, indicating that the field in the core is well aligned with the magnetic field in lower-density regions of the cloud probed by near-infrared observations and also the cloud-scale magnetic field traced by Planck observations. The polarization percentage ($P$) decreases with an increasing total intensity ($I$) with a power-law index of $-$1.03 $\pm$ 0.05. We estimate the plane-of-sky field strength ($B_{\mathrm{pos}}$) using modified Davis-Chandrasekhar-Fermi (DCF) methods based on structure function (SF), auto-correlation (ACF), and unsharp masking (UM) analyses. We find that the estimates from the SF, ACF, and UM methods yield strengths of 103 $\pm$ 46 $\mu$G, 136 $\pm$ 69 $\mu$G, and 213 $\pm$ 115 $\mu$G, respectively. Our calculations suggest that the Ophiuchus C core is near magnetically critical or slightly magnetically supercritical (i.e. unstable to collapse). The total magnetic energy calculated from the SF method is comparable to the turbulent energy in Ophiuchus C, while the ACF method and the UM method only set upper limits for the total magnetic energy because of large uncertainties., Comment: 22 pages, 12 figures
Published: 2019
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Category

Publication Type

Journal

Region

Database

Publisher

1,253 results on '"THOMPSON, DEREK"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources