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Your search keyword '"Moriarty-Schieven, Gerald H."' showing total 10 results
Start Over Author "Moriarty-Schieven, Gerald H." Topic astrophysics - astrophysics of galaxies
10 results on '"Moriarty-Schieven, Gerald H."'

1. 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
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2. Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE

Author

Park, Wooseok, Lee, Jeong-Eun, Peña, Carlos Contreras, Johnstone, Doug, Herczeg, Gregory, Lee, Sieun, Lee, Seonjae, Bhardwaj, Anupam, and Moriarty-Schieven, Gerald H.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

Variability in young stellar objects (YSOs) can be caused by various time-dependent phenomena associated with star formation, including accretion rates, geometric changes in the circumstellar disks, stochastic hydromagnetic interactions between stellar surfaces and inner disk edges, reconnections within the stellar magnetosphere, and hot/cold spots on stellar surfaces. We uncover and characterize $\sim$1700 variables from a sample of $\sim$5400 YSOs in nearby low-mass star-forming regions using mid-IR light curves obtained from the 6.5-years NEOWISE All Sky Survey. The mid-IR variability traces a wide range of dynamical, physical, and geometrical phenomenon. We classify six types of YSO mid-IR variability based on their light curves: secular variability ($Linear, Curved, Periodic$) and stochastic variability ($Burst, Drop, Irregular$). YSOs in earlier evolutionary stages have higher fractions of variables and higher amplitudes for the variability, with the recurrence timescale of FUor-type outbursts (defined here as $\Delta$W1 or $\Delta$W2 $>1$ mag followed by inspection of candidates) of $\sim$1000 years in the early embedded protostellar phase. Known eruptive young stars and subluminous objects show fractions of variables similar to the fraction ($\sim55\%$) found in typical protostars, suggesting that these two distinct types are not distinct in variability over the 6.5-year timescale. Along with brightness variability, we also find a diverse range of secular color variations, which can be attributed to a competitive interplay between the variable accretion luminosity of the central source and the variable extinction by material associated with the accretion process., Comment: Accepted for publication in ApJ

Published
2021
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3. The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars

Author

Lee, Yong-Hee, Johnstone, Doug, Lee, Jeong-Eun, Herczeg, Gregory, Mairs, Steve, Contreras-Peña, Carlos, Hatchell, Jennifer, Naylor, Tim, Bell, Graham S., Bourke, Tyler L., Broughton, Colton, Francis, Logan, Gupta, Aashish, Harsono, Daniel, Liu, Sheng-Yuan, Park, Geumsook, Plovie, Spencer, Moriarty-Schieven, Gerald H., Scholz, Aleks, Sharma, Tanvi, Teixeira, Paula Stella, Wang, Yao-Te, Aikawa, Yuri, Bower, Geoffrey C., Chen, Huei-Ru Vivien, Bae, Jaehan, Baek, Giseon, Chapman, Scott, Chen, Wen Ping, Du, Fujun, Dutta, Somnath, Forbrich, Jan, Guo, Zhen, Inutsuka, Shu-ichiro, Kang, Miju, Kirk, Helen, Kuan, Yi-Jehng, Kwon, Woojin, Lai, Shih-Ping, Lalchand, Bhavana, Lane, James M. M., Lee, Chin-Fei, Liu, Tie, Morata, Oscar, Pearson, Samuel, Pon, Andy, Sahu, Dipen, Shang, Hsien, Stamatellos, Dimitris, Tang, Shih-Yun, Xu, Ziyan, and Yoo, Hyunju

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We present the four-year survey results of monthly submillimeter monitoring of eight nearby ($< 500 $pc) star-forming regions by the JCMT Transient Survey. We apply the Lomb-Scargle Periodogram technique to search for and characterize variability on 295 submillimeter peaks brighter than 0.14 Jy beam$^{-1}$, including 22 disk sources (Class II), 83 protostars (Class 0/I), and 190 starless sources. We uncover 18 secular variables, all of them protostars. No single-epoch burst or drop events and no inherently stochastic sources are observed. We classify the secular variables by their timescales into three groups: Periodic, Curved, and Linear. For the Curved and Periodic cases, the detectable fractional amplitude, with respect to mean peak brightness, is $\sim4$ % for sources brighter than $\sim$ 0.5 Jy beam$^{-1}$. Limiting our sample to only these bright sources, the observed variable fraction is 37 % (16 out of 43). Considering source evolution, we find a similar fraction of bright variables for both Class 0 and Class I. Using an empirically motivated conversion from submillimeter variability to variation in mass accretion rate, six sources (7 % of our full sample) are predicted to have years-long accretion events during which the excess mass accreted reaches more than 40 % above the total quiescently accreted mass: two previously known eruptive Class I sources, V1647 Ori and EC 53 (V371 Ser), and four Class 0 sources, HOPS 356, HOPS 373, HOPS 383, and West 40. Considering the full protostellar ensemble, the importance of episodic accretion on few years timescale is negligible, only a few percent of the assembled mass. However, given that this accretion is dominated by events of order the observing time-window, it remains uncertain as to whether the importance of episodic events will continue to rise with decades-long monitoring., Comment: Accepted for publication in the Astrophysical Journal

Published
2021
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4. 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
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5. 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
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6. 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
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7. JCMT BISTRO survey: Magnetic Fields within the Hub-Filament Structure in IC 5146

Author

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

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the 850 $\mu$m polarization observations toward the IC5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope (JCMT), as part of the B-fields In STar forming Regions Observations (BISTRO). This work is aimed at revealing the magnetic field morphology within a core-scale ($\lesssim 1.0$ pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether or not the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function (PDF) of the observed polarization fraction for low signal-to-noise ratio (SNR) data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in $A_V\sim$ 20--300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5$\pm$0.2 mG toward the central hub using the Davis-Chandrasekhar-Fermi method, corresponding to a mass-to-flux criticality of $\sim$ $1.3\pm0.4$ and an Alfv\'{e}nic Mach number of $<$0.6. These results suggest that gravity and magnetic field is currently of comparable importance in the HFS, and turbulence is less important., Comment: 24 pages, 15 figures, accepted for publication in ApJ

Published
2018
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8. Magnetic fields towards Ophiuchus-B derived from SCUBA-2 polarization measurements

Author

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

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope (JCMT) in Hawaii. This work is part of the B-fields In Star-forming Region Observations (BISTRO) survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over $\sim$0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically towards the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630$\pm$410 $\mu$G in the Oph-B2 sub-clump using a Davis-Chandeasekhar-Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio $\lambda$= 1.6$\pm$1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical., Comment: 17 pages, 10 figures, Accepted for publication in ApJ

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

Author

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

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present 850 $\mu$m imaging polarimetry data of the $\rho$ Oph-A core taken with the Submillimeter Common-User Bolometer Array-2 (SCUBA-2) and its polarimeter (POL-2), as part of our ongoing survey project, BISTRO (B-fields In STar forming RegiOns). The polarization vectors are used to identify the orientation of the magnetic field projected on the plane of the sky at a resolution of 0.01 pc. We identify 10 subregions with distinct polarization fractions and angles in the 0.2 pc $\rho$ Oph A core; some of them can be part of a coherent magnetic field structure in the $\rho$ Oph region. The results are consistent with previous observations of the brightest regions of $\rho$ Oph-A, where the degrees of polarization are at a level of a few percents, but our data reveal for the first time the magnetic field structures in the fainter regions surrounding the core where the degree of polarization is much higher ($> 5 \%$). A comparison with previous near-infrared polarimetric data shows that there are several magnetic field components which are consistent at near-infrared and submillimeter wavelengths. Using the Davis-Chandrasekhar-Fermi method, we also derive magnetic field strengths in several sub-core regions, which range from approximately 0.2 to 5 mG. We also find a correlation between the magnetic field orientations projected on the sky with the core centroid velocity components., Comment: 22 pages, 11 figures, accepted for publication in ApJ

Published
2018
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10. First results from BISTRO -- a SCUBA-2 polarimeter survey of the Gould Belt

Author

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

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2) camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope (JCMT) in Hawaii. We discuss the survey's aims and objectives. We describe the rationale behind the survey, and the questions which the survey will aim to answer. The most important of these is the role of magnetic fields in the star formation process on the scale of individual filaments and cores in dense regions. We describe the data acquisition and reduction processes for POL-2, demonstrating both repeatability and consistency with previous data. We present a first-look analysis of the first results from the BISTRO survey in the OMC 1 region. We see that the magnetic field lies approximately perpendicular to the famous 'integral filament' in the densest regions of that filament. Furthermore, we see an 'hour-glass' magnetic field morphology extending beyond the densest region of the integral filament into the less-dense surrounding material, and discuss possible causes for this. We also discuss the more complex morphology seen along the Orion Bar region. We examine the morphology of the field along the lower-density north-eastern filament. We find consistency with previous theoretical models that predict magnetic fields lying parallel to low-density, non-self-gravitating filaments, and perpendicular to higher-density, self-gravitating filaments., Comment: 12 pages, 8 figures, accepted for publication in ApJ

Published
2017
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