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1. Benchmarked RADARSAT-2, SENTINEL-1 and RADARSAT Constellation Mission Change-Detection Monitoring at North Slide, Thompson River Valley, British Columbia: ensuring a Landslide-Resilient National Railway Network

Author: David Huntley, Drew Rotheram-Clarke, Andy Pon, Alex Tomaszewicz, Jon Leighton, Robert Cocking, and Jamel Joseph
Subjects: Environmental sciences, GE1-350, Technology
Abstract: In this research note, we demonstrate the applicability of interferometric analyses (InSAR) of RADARSAT 2 (RS2), SENTINEL 1 (S1) and RADARSAT Constellation Mission (RCM) datasets to characterize and monitor landslides along a high-risk section of the national railway transportation corridor traversing the Thompson River valley, British Columbia. As a geomorphically active landform, the North Slide is an ideal case study for field-testing and evaluating slope change-detection monitoring incorporating satellite, aerial and ground-based geospatial technologies. RS2, S1 and RCM InSAR datasets provide valuable baseline spatial and temporal information on movement of the landslide near critical railway infrastructure when benchmarked with real-time kinematic (RTK) global navigation satellite system (GNSS) measurements, uninhabited aerial vehicle (UAV) photogrammetry, bathymetric soundings, and ground observations. We demonstrate that monitoring unstable slopes and infrastructure at risk with multiple high spatial- and temporal-resolution satellite SAR platforms is a cost-effective natural hazard management practice that also provides important geoscience information to help develop appropriate mitigation and climate adaptation measures.
Published: 2021
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2. Benchmarked RADARSAT-2, SENTINEL-1 and RADARSAT Constellation Mission Change-Detection Monitoring at North Slide, Thompson River Valley, British Columbia: ensuring a Landslide-Resilient National Railway Network

Author: Jon Leighton, Andy Pon, Jamel Joseph, Drew Rotheram-Clarke, Alex Tomaszewicz, Robert Cocking, and David Huntley
Subjects: River valley, Interferometric synthetic aperture radar, General Earth and Planetary Sciences, Landslide, Geology, Change detection, Constellation, Remote sensing
Abstract: In this research note, we demonstrate the applicability of interferometric analyses (InSAR) of RADARSAT 2 (RS2), SENTINEL 1 (S1) and RADARSAT Constellation Mission (RCM) datasets to characterize an...
Published: 2021
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3. The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming Region

Author: Simon Coudé, Pierre Bastien, Martin Houde, Sarah Sadavoy, Rachel Friesen, James Di Francesco, Doug Johnstone, Steve Mairs, Tetsuo Hasegawa, Woojin Kwon, Shih-Ping Lai, Keping Qiu, Derek Ward-Thompson, David Berry, Michael Chun-Yuan Chen, Jason Fiege, Erica Franzmann, Jennifer Hatchell, Kevin Lacaille, Brenda C. Matthews, Gerald H. Moriarty-Schieven, Andy Pon, Philippe André, Doris Arzoumanian, Yusuke Aso, Do-Young Byun, Chakali Eswaraiah, Huei-Ru Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Yasuo Doi, Emily Drabek-Maunder, C. Darren Dowell, Stewart P. S. Eyres, Sam Falle, Per Friberg, Gary Fuller, Ray S. Furuya, Tim Gledhill, Sarah F. Graves, Jane S. Greaves, Matt J. Griffin, Qilao Gu, Saeko S. Hayashi, Thiem Hoang, Wayne Holland, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Yoshihiro Kanamori, Akimasa Kataoka, Ji-hyun Kang, Miju Kang, Sung-ju Kang, Koji S. Kawabata, Francisca Kemper, Gwanjeong Kim, Jongsoo Kim, Kee-Tae Kim, Kyoung Hee Kim, Mi-Ryang Kim, Shinyoung Kim, Jason M. Kirk, Masato I. N. Kobayashi, Patrick M. Koch, Jungmi Kwon, Jeong-Eun Lee, Chang Won Lee, Sang-Sung Lee, Dalei Li, Di Li, Hua-bai Li, Hong-Li Liu, Junhao Liu, Sheng-Yuan Liu, Tie Liu, Sven van Loo, A-Ran Lyo, Masafumi Matsumura, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Takashi Onaka, Harriet Parsons, Kate Pattle, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Mark G. Rawlings, Brendan Retter, John Richer, Andrew Rigby, Jean-François Robitaille, Hiro Saito, Giorgio Savini, Anna M. M. Scaife, Masumichi Seta, Hiroko Shinnaga, Archana Soam, Motohide Tamura, Ya-Wen Tang, Kohji Tomisaka, Yusuke Tsukamoto, Hongchi Wang, Jia-Wei Wang, Anthony P. Whitworth, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Tetsuya Zenko, Chuan-Peng Zhang, Guoyin Zhang, Jianjun Zhou, and Lei Zhu
Published: 2019
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4. The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars

Author: Jonathan M. C. Rawlings, Helen Kirk, Dipen Sahu, Oscar Morata, Samuel Pearson, Yuri Aikawa, James Lane, Aashish Gupta, Jaehan Bae, Fujun Du, Shu-ichiro Inutsuka, Daniel Harsono, Geumsook Park, Giseon Baek, Yi-Jehng Kuan, Geoffrey C. Bower, Gregory J. Herczeg, Spencer Plovie, Aleks Scholz, Doug Johnstone, Chin-Fei Lee, Zhen Guo, Hsien Shang, Hyunju Yoo, Graham S. Bell, Jeong-Eun Lee, Yong-Hee Lee, Carlos Contreras-Peña, Woojin Kwon, Paula S. Teixeira, Sheng-Yuan Liu, Gerald H. Moriarty-Schieven, Bhavana Lalchand, Somnath Dutta, Jan Forbrich, Ziyan Xu, Shih-Yun Tang, Huei-Ru Vivien Chen, Dimitris Stamatellos, Jennifer Hatchell, Colton Broughton, Tim Naylor, Wen Ping Chen, Yao-Te Wang, Tanvi Sharma, Tyler L. Bourke, Andy Pon, Steve Mairs, Shih-Ping Lai, Logan Francis, Miju Kang, Scott Chapman, Tie Liu, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: Variable stars, FOS: Physical sciences, 01 natural sciences, 0103 physical sciences, QB Astronomy, Protostar, FU Orionis stars, 14. Life underwater, Pre-main sequence stars, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QC, QB, Physics, 010308 nuclear & particles physics, Star formation, F510, Astronomy, Astronomy and Astrophysics, 3rd-DAS, Astrophysics - Astrophysics of Galaxies, Young stellar objects, Protostars, QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Transient (oscillation), Submillimeter astronomy
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., Accepted for publication in the Astrophysical Journal
Published: 2021

5. Brumadinho Dam InSAR study: analysis of TerraSAR-X, COSMO-SkyMed and Sentinel-1 images preceding the collapse

Author: Andy Pon, Stephen Donegan, and David Holden
Subjects: Synthetic aperture radar, Remote sensing (archaeology), Interferometric synthetic aperture radar, Satellite constellation, Satellite imagery, Satellite, Scale (map), Dam Collapse, Geology, Remote sensing
Abstract: The catastrophic failure of Dam I at the Corrego do Feijao iron ore mine near Brumadinho, Brazil has brought significant attention to the range of monitoring techniques available for similar sites, including satellite Interferometric Synthetic Aperture Radar (InSAR). Satellite InSAR is a remote sensing technique that uses satellite imagery to detect millimetre scale displacements. This paper presents InSAR results covering the Brumadinho site, for the time period leading up to the dam collapse, using both high and low resolution imagery from four sets of satellite synthetic aperture radar (SAR) data. The goal of this study is to provide a set of results that may help to improve the understanding of the mechanisms behind the collapse and to understand if there was a role that InSAR could have played in detecting any anomalous displacement signals before the collapse. Four sets of satellite SAR images are available and have been analysed in this study. These include two from the Sentinel-1 (S1) satellite constellation, which have a lower resolution (20 m), and two from the higher resolution (3 m) TerraSAR-X (TSX) and COSMO-SkyMed (CSK) satellite constellations. The high resolution CSK and TSX measurements also provide a much greater level of detail on the dam that can be used to distinguish local trends. Some subtle signals are observed on the lower portion of the dam wall in the year leading up to the collapse, however, these are not statistically significant based solely on the level of noise present in the InSAR results. At the top of the wall and inside of the enclosure, significant signal is present, as expected for a structure of this type.
Published: 2020
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6. JCMT BISTRO Survey: Magnetic Fields within the Hub-filament Structure in IC 5146

Author: Jia-Wei Wang, Shih-Ping Lai, Chakali Eswaraiah, Kate Pattle, James Di Francesco, Doug Johnstone, Patrick M. Koch, Tie Liu, Motohide Tamura, Ray S. Furuya, Takashi Onaka, Derek Ward-Thompson, Archana Soam, Kee-Tae Kim, Chang Won Lee, Chin-Fei Lee, Steve Mairs, Doris Arzoumanian, Gwanjeong Kim, Thiem Hoang, Jihye Hwang, Sheng-Yuan Liu, David Berry, Pierre Bastien, Tetsuo Hasegawa, Woojin Kwon, Keping Qiu, Philippe André, Yusuke Aso, Do-Young Byun, Huei-Ru Chen, Michael C. Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Simon Coudé, Yasuo Doi, C. Darren Dowell, Emily Drabek-Maunder, Hao-Yuan Duan, Stewart P. S. Eyres, Sam Falle, Lapo Fanciullo, Jason Fiege, Erica Franzmann, Per Friberg, Rachel K. Friesen, Gary Fuller, Tim Gledhill, Sarah F. Graves, Jane S. Greaves, Matt J. Griffin, Qilao Gu, Ilseung Han, Jennifer Hatchell, Saeko S. Hayashi, Wayne Holland, Martin Houde, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Yoshihiro Kanamori, Ji-hyun Kang, Miju Kang, Sung-ju Kang, Akimasa Kataoka, Koji S. Kawabata, Francisca Kemper, Jongsoo Kim, Kyoung Hee Kim, Mi-Ryang Kim, Shinyoung Kim, Jason M. Kirk, Masato I. N. Kobayashi, Vera Konyves, Jungmi Kwon, Kevin M. Lacaille, Hyeseung Lee, Jeong-Eun Lee, Sang-Sung Lee, Yong-Hee Lee, Dalei Li, Di Li, Hua-bai Li, Hong-Li Liu, Junhao Liu, A-Ran Lyo, Masafumi Matsumura, Brenda C. Matthews, Gerald H. Moriarty-Schieven, Tetsuya Nagata, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Geumsook Park, Harriet Parsons, Enzo Pascale, Nicolas Peretto, Andy Pon, Tae-Soo Pyo, Lei Qian, Ramprasad Rao, Mark G. Rawlings, Brendan Retter, John Richer, Andrew Rigby, Jean-François Robitaille, Sarah Sadavoy, Hiro Saito, Giorgio Savini, Anna M. M. Scaife, Masumichi Seta, Hiroko Shinnaga, Ya-Wen Tang, Kohji Tomisaka, Yusuke Tsukamoto, Sven van Loo, Hongchi Wang, Anthony P. Whitworth, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Hyeong-Sik Yun, Tetsuya Zenko, Chuan-Peng Zhang, Guoyin Zhang, Ya-Peng Zhang, Jianjun Zhou, and Lei Zhu
Subjects: individual objects (IC 5146) [ISM], 010504 meteorology & atmospheric sciences, FOS: Physical sciences, ISM [radio continuum], Probability density function, Astrophysics, 01 natural sciences, law.invention, Protein filament, ISM: individual objects (IC 5146), ISM: magnetic fields, ISM: structure, polarization, radio continuum: ISM, stars: formation, law, 0103 physical sciences, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, formation [stars], Turbulence, F510, Bolometer, magnetic fields [ISM], Astronomy and Astrophysics, Polarimeter, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), structure [ISM]
Abstract: We present the 850 $\mu$m polarization observations toward the IC5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope (JCMT), as part of the B-fields In STar forming Regions Observations (BISTRO). This work is aimed at revealing the magnetic field morphology within a core-scale ($\lesssim 1.0$ pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether or not the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function (PDF) of the observed polarization fraction for low signal-to-noise ratio (SNR) data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in $A_V\sim$ 20--300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5$\pm$0.2 mG toward the central hub using the Davis-Chandrasekhar-Fermi method, corresponding to a mass-to-flux criticality of $\sim$ $1.3\pm0.4$ and an Alfv\'{e}nic Mach number of $, Comment: 24 pages, 15 figures, accepted for publication in ApJ
Published: 2019
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7. ALMA detections of the youngest protostars in Ophiuchus

Author: J. Di Francesco, Tyler L. Bourke, Andy Pon, Jaime E. Pineda, Rachel Friesen, Jes K. Jørgensen, and Paola Caselli
Subjects: Physics, Spectral index, 010308 nuclear & particles physics, Molecular cloud, Extinction (astronomy), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Bipolar outflow, 0103 physical sciences, Ophiuchus, Protostar, Continuum (set theory), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.1 mm dust continuum and CO 2-1 emission toward six dense cores within the Ophiuchus molecular cloud. We detect compact, sub-arcsecond continuum structures toward three targets, two of which (Oph A N6 and SM1) are located in the Ophiuchus A ridge. Two targets, SM1 and GSS 30, contain two compact sources within the ALMA primary beam. We argue that several of the compact structures are small ($R \lesssim 80$ au) accretion disks around young protostars, due to their resolved, elongated structures, coincident radio and x-ray detections, or bipolar outflow detections. While CO line wings extend to $\pm 10-20$ km s$^{-1}$ for the more evolved sources GSS 30 IRS3 and IRS1, CO emission toward other sources, where detected, only extends a few km s$^{-1}$ from the cloud $v_\mathrm{LSR}$. The dust spectral index toward the compact objects suggests that the disks are either optically thick at 1.1 mm, or that significant grain growth has already occurred. We identify, for the first time, a single compact continuum source ($R \sim 100$ au) toward N6 embedded within a larger continuum structure. SM1N is extended in the continuum but is highly centrally concentrated, with a density profile that follows a $r^{-1.3}$ power law within 200 au, and additional structure suggested by the uv-data. Both N6 and SM1N show no clear bipolar outflows with velocities greater than a few km s$^{-1}$ from the cloud velocity. These sources are candidates to be the youngest protostars or first hydrostatic cores in the Ophiuchus molecular cloud., 19 pages, 10 figures, accepted to ApJ
Published: 2018

8. A First Look at BISTRO Observations of The $\rho$ Oph-A core

Author: Jungmi Kwon, Yasuo Doi, Motohide Tamura, Masafumi Matsumura, Kate Pattle, David Berry, Sarah Sadavoy, Brenda C. Matthews, Derek Ward-Thompson, Tetsuo Hasegawa, Ray S. Furuya, Andy Pon, James Di Francesco, Doris Arzoumanian, Saeko S. Hayashi, Koji S. Kawabata, Takashi Onaka, Minho Choi, Miju Kang, Thiem Hoang, Chang Won Lee, Sang-Sung Lee, Hong-Li Liu, Tie Liu, Shu-ichiro Inutsuka, Chakali Eswaraiah, Pierre Bastien, Woojin Kwon, Shih-Ping Lai, Keping Qiu, Simon Coudé, Erica Franzmann, Per Friberg, Sarah F. Graves, Jane S. Greaves, Martin Houde, Doug Johnstone, Jason M. Kirk, Patrick M. Koch, Di Li, Harriet Parsons, Ramprasad Rao, Mark G. Rawlings, Hiroko Shinnaga, Sven van Loo, Yusuke Aso, Do-Young Byun, Huei-Ru Chen, Mike C.-Y. Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Antonio Chrysostomou, Eun Jung Chung, Emily Drabek-Maunder, Stewart P. S. Eyres, Jason Fiege, Rachel K. Friesen, Gary Fuller, Tim Gledhill, Matt J. Griffin, Qilao Gu, Jennifer Hatchell, Wayne Holland, Tsuyoshi Inoue, Kazunari Iwasaki, Il-Gyo Jeong, Ji-hyun Kang, Sung-ju Kang, Francisca Kemper, Gwanjeong Kim, Jongsoo Kim, Kee-Tae Kim, Kyoung Hee Kim, Mi-Ryang Kim, Shinyoung Kim, Kevin M. Lacaille, Jeong-Eun Lee, Dalei Li, Hua-bai Li, Junhao Liu, Sheng-Yuan Liu, A-Ran Lyo, Steve Mairs, Gerald H. Moriarty-Schieven, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Brendan Retter, John Richer, Andrew Rigby, Jean-Franois Robitaille, Giorgio Savini, Anna M. M. Scaife, Archana Soam, Ya-Wen Tang, Kohji Tomisaka, Hongchi Wang, Jia-Wei Wang, Anthony P. Whitworth, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Chuan-Peng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Philippe André, C. Darren Dowell, Sam Falle, Yusuke Tsukamoto, Takao Nakagawa, Yoshihiro Kanamori, Akimasa Kataoka, Masato I. N. Kobayashi, Tetsuya Nagata, Hiro Saito, Masumichi Seta, and Tetsuya Zenko
Subjects: 010504 meteorology & atmospheric sciences, ISM: structure, media_common.quotation_subject, Polarimetry, ISM [radio continuum], Astrophysics, individual objects (Ophiuchi) [ISM], Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, circumstellar matter, law.invention, ISM: individual objects (Ophiuchi), law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, F990, polarization, formation [stars], Bolometer, Polarimeter, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, radio, Wavelength, Sky, Space and Planetary Science, Degree of polarization, structure [ISM]
Abstract: 著者人数: 122名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 權, 靜美; 中西, 裕之; 中川, 貴雄）, Accepted: 2018-03-26, 資料番号: SA1170332000
Published: 2018
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9. Similar complex kinematics within two massive, filamentary infrared dark clouds

Author: Francesco Fontani, Andy Pon, Izaskun Jiménez-Serra, Jonathan D. Henshaw, Paola Caselli, Ashley T. Barnes, Sarah Ragan, and Jonathan C. Tan
Subjects: Physics, 010308 nuclear & particles physics, Infrared, Star formation, Milky Way, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Kinematics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Protein filament, symbols.namesake, Mach number, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, symbols, Spectral resolution, 010303 astronomy & astrophysics, QB, Envelope (waves)
Abstract: Infrared dark clouds (IRDCs) are thought to be potential hosts of the elusive early phases of high-mass star formation. Here, we conduct an in-depth kinematic analysis of one such IRDC, G034.43+00.24 (Cloud F), using high sensitivity and high spectral resolution IRAM-30m N2H+ (1-0) and C18O (1-0) observations. To disentangle the complex velocity structure within this cloud, we use Gaussian decomposition and hierarchical clustering algorithms. We find that four distinct coherent velocity components are present within Cloud F. The properties of these components are compared to those found in a similar IRDC, G035.39-00.33 (Cloud H). We find that the components in both clouds have high densities (inferred by their identification in N2H+), trans-to-supersonic non-thermal velocity dispersions with Mach numbers of ∼1.5-4, a separation in velocity of ∼3 km s-1, and a mean red-shift of ∼0.3 km s-1 between the N2H+ (dense gas) and C18O emission (envelope gas). The latter of these could suggest that these clouds share a common formation scenario. We investigate the kinematics of the larger-scale Cloud F structures, using lower-density-tracing 13CO(1-0) observations. A good correspondence is found between the components identified in the IRAM-30m observations and the most prominent component in the 13CO data. We find that the IRDC Cloud F is only a small part of a much larger structure, which appears to be an inter-arm filament of the Milky Way.
Published: 2018

10. The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

Author: Andy Pon, Andrea Bracco, and Juan D. Soler
Subjects: Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Orion–Eridanus Superbubble, Magnetic field, symbols.namesake, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, symbols, Disc, Planck, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of microGauss toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble., 7 pages, 8 figures. Accepted for publication as a Letter in A&A, section 1. Letters to the Editor (08/12/2017)
Published: 2018
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11. Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544

Author: Jonathan Holdship, Ana Chacón-Tanarro, Ana López-Sepulcre, Vianney Taquet, Claudio Codella, J. Laas, D. Quenard, Francesco Fontani, P. Hily-Blant, Ali Jaber Al-Edhari, Cécile Favre, Linda Podio, Serena Viti, Nami Sakai, Yoko Oya, Leonardo Testi, Jaime E. Pineda, Patrice Theulé, J. Ospina-Zamudio, François Dulieu, Luca Bizzocchi, Emmanuel Caux, Albert Rimola, E. Bianchi, Roberto Neri, Nadia Balucani, Anton Vasyunin, Anna Punanova, Izaskun Jiménez-Serra, Rumpa Choudhury, Sandrine Bottinelli, Rafael Bachiller, Bertrand Lefloch, Piero Ugliengo, Claudine Kahane, Andy Pon, S. Spezzano, Satoshi Yamamoto, Felipe O. Alves, Cecilia Ceccarelli, Ian R. Sims, Siyi Feng, Charlotte Vastel, Paola Caselli, Ural Federal University [Ekaterinburg] (UrFU), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), Queen Mary University of London (QMUL), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), University of Western Ontario (UWO), INAF - Osservatorio Astrofisico di Arcetri (OAA), University of Electro-Communications [Tokyo] (UEC), Università degli Studi di Perugia (UNIPG), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Universitat Autònoma de Barcelona (UAB), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Universiteit Leiden [Leiden], Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Ortopedia e Medicina del Lavoro, Università degli Studi di Torino, 10126 Turin, European Research Council (ERC) [PALs 320620], CITA National Fellowship, STFC [ST/L004801, ST/M004139], STFC through an Ernest Rutherford Fellowship, ERC [DOC 741002], Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia = University of Perugia (UNIPG), Università degli Studi di Firenze = University of Florence (UniFI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Universiteit Leiden, Università degli studi di Torino = University of Turin (UNITO), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Firenze [Firenze], PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Universitat Autònoma de Barcelona [Barcelona] (UAB)
Subjects: ISM kinematics and dynamics, ISM individual objects (L1544), radio lines ISM, Thermodynamic equilibrium, Continuum (design consultancy), FOS: Physical sciences, ISM: clouds, 01 natural sciences, Molecular physics, ISM molecules, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ISM: kinematics and dynamics, Physics, [PHYS]Physics [physics], ISM: individual objects (L1544), ISM: molecules, radio lines: ISM, stars: formation, Astronomy and Astrophysics, Space and Planetary Science, Accretion (meteorology), 010308 nuclear & particles physics, Velocity dispersion, Rotational temperature, Static core, Astrophysics - Astrophysics of Galaxies, stars formation, Core (optical fiber), ISM clouds, Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), astrochimica, Order of magnitude
Abstract: Towards the pre-stellar core L1544, the methanol (CH$_3$OH) emission forms an asymmetric ring around the core centre, where CH$_3$OH is mostly in solid form, with a clear peak 4000~au to the north-east of the dust continuum peak. As part of the NOEMA Large Project SOLIS (Seeds of Life in Space), the CH$_3$OH peak has been spatially resolved to study its kinematics and physical structure and to investigate the cause behind the local enhancement. We find that methanol emission is distributed in a ridge parallel to the main axis of the dense core. The centroid velocity increases by about 0.2~km~s$^{-1}$ and the velocity dispersion increases from subsonic to transonic towards the central zone of the core, where the velocity field also shows complex structure. This could be indication of gentle accretion of material onto the core or interaction of two filaments, producing a slow shock. We measure the rotational temperature and show that methanol is in local thermodynamic equilibrium (LTE) only close to the dust peak, where it is significantly depleted. The CH$_3$OH column density, $N_{tot}({\rm CH_3OH})$, profile has been derived with non-LTE radiative transfer modelling and compared with chemical models of a static core. The measured $N_{tot}({\rm CH_3OH})$ profile is consistent with model predictions, but the total column densities are one order of magnitude lower than those predicted by models, suggesting that the efficiency of reactive desorption or atomic hydrogen tunnelling adopted in the model may be overestimated; or that an evolutionary model is needed to better reproduce methanol abundance., 19 pages, 18 figures. Accepted by ApJ
Published: 2018
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12. Magnetic fields towards Ophiuchus-b derived from scuba-2 polarization measurements

Author: Patrick M. Koch, Gary A. Fuller, Takashi Onaka, Pierre Bastien, Archana Soam, Philippe André, Jihye Hwang, Tetsuya Zenko, Tim Gledhill, Jia-Wei Wang, Rachel Friesen, Andy Pon, Sarah Graves, Jongsoo Kim, Steve Mairs, Jungmi Kwon, Tetsuya Nagata, Giorgio Savini, Hiroko Shinnaga, Kate Pattle, Wen Ping Chen, Yusuke Tsukamoto, Chang Won Lee, Hsi-Wei Yen, Shih-Ping Lai, John Richer, Thiem Hoang, Kee-Tae Kim, Jungyeon Cho, Sarah Sadavoy, Doris Arzoumanian, Kevin Lacaille, Hiroyuki Nakanishi, David Berry, Dalei Li, Hyeseung Lee, Hong-Li Liu, Gwanjeong Kim, Sang-Sung Lee, C. Darren Dowell, Anthony Peter Whitworth, Woojin Kwon, Mi-Ryang Kim, Derek Ward-Thompson, Ray S. Furuya, Sheng-Yuan Liu, Sung-ju Kang, Jianjun Zhou, Eun Jung Chung, Hiro Saito, Emily Drabek-Maunder, Brenda C. Matthews, Motohide Tamura, Koji S. Kawabata, Junhao Liu, Yoshihiro Kanamori, Ya-Wen Tang, Minho Choi, Chakali Eswaraiah, Saeko S. Hayashi, Tae-Soo Pyo, Keping Qiu, Francisca Kemper, Shu-ichiro Inutsuka, Lei Qian, James Di Francesco, Shinyoung Kim, Tie Liu, Tsuyoshi Inoue, Chuan-Peng Zhang, Yusuke Aso, Matthew Joseph Griffin, Kazunari Iwasaki, S. P. S. Eyres, Miju Kang, Jane Greaves, Tetsuo Hasegawa, Anna M. M. Scaife, Kohji Tomisaka, Do-Young Byun, J. F. Robitaille, Sam Falle, Jinghua Yuan, Masafumi Matsumura, Nicolas Peretto, Antonio Chrysostomou, Guoyin Zhang, Akimasa Kataoka, Hyunju Yoo, Qilao Gu, Wayne S. Holland, Sven Van Loo, Mark G. Rawlings, Ilseung Han, Simon Coudé, Masumichi Seta, M. Chen, Huei-Ru Chen, Lei Zhu, Harriet Parsons, Yasuo Doi, Hongchi Wang, Ji-hyun Kang, Hua-bai Li, Jason Fiege, Il-Gyo Jeong, Per Friberg, Kyoung Hee Kim, Jennifer Hatchell, Ramprasad Rao, Di Li, Gerald H. Moriarty-Schieven, Doug Johnstone, Brendan Retter, Masato I. N. Kobayashi, Martin Houde, Fumitaka Nakamura, A-Ran Lyo, Jason M. Kirk, Nagayoshi Ohashi, Erica Franzmann, Andrew Rigby, Tao-Chung Ching, and Jeong-Eun Lee
Subjects: Field line, ISM: structure, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, James Clerk Maxwell Telescope, Astrophysics::Galaxy Astrophysics, QB, Physics, polarization, stars: formation, 010308 nuclear & particles physics, Star formation, ISM: individual objects (Ophiuchus), Molecular cloud, Astronomy and Astrophysics, Polarization (waves), Astrophysics - Astrophysics of Galaxies, Magnetic field, radio continuum: ISM, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ophiuchus, Degree of polarization, Astrophysics::Earth and Planetary Astrophysics
Abstract: 著者人数: 124名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 權, 靜美), Accepted: 2018-05-10, 資料番号: SA1180101000
Published: 2018
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13. Widespread SiO and CH3OH Emission in Filamentary Infrared-Dark Clouds★

Author: Jonathan C. Tan, Jonathan D. Henshaw, S Viti, Ashley T. Barnes, Andy Pon, Giuseppe Cosentino, Im Jimenez-Serra, Paola Caselli, and Francesco Fontani
Subjects: Physics, Chemical content, education.field_of_study, 010308 nuclear & particles physics, Star formation, Infrared, Population, Extinction (astronomy), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Velocity space, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Infrared-Dark Clouds (IRDCs) are cold, dense regions of high (optical and infrared) extinction, believed to be the birthplace of high-mass stars and stellar clusters. The physical mechanisms leading to the formation of these IRDCs are not completely understood and it is thus important to study their molecular gas kinematics and chemical content to search for any signature of the IRDCs formation process. Using the 30m-diameter antenna at the Instituto de Radioastronom\'ia Milim\'etrica, we have obtained emission maps of dense gas tracers (H$^{13}$CO$^{+}$ and HN$^{13}$C) and typical shock tracers (SiO and CH$_3$OH) toward three IRDCs, G028.37+00.07, G034.43+00.24 and G034.77-00.55 (clouds C, F and G, respectively). We have studied the molecular gas kinematics in these clouds and, consistent with previous works toward other IRDCs, the clouds show complex gas kinematics with several velocity-coherent sub-structures separated in velocity space by a few km s$^{-1}$. Correlated with these complex kinematic structures, widespread (parsec-scale) emission of SiO and CH$_3$OH is present in all the three clouds. For clouds C and F, known to be actively forming stars, widespread SiO and CH$_3$OH is likely associated with on-going star formation activity. However, for cloud G, which lacks either 8 $\mu$m or 24 $\mu$m sources and 4.5 $\mu$m H$_2$ shock-excited emission, the detected widespread SiO and CH$_3$OH emission may have originated in a large-scale shock interaction, although a scenario involving a population of low-mass stars driving molecular outflows cannot be fully ruled out., Comment: 23 pages, 12 figures. Accepted for publication in MNRAS
Published: 2017
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14. The JCMT Transient Survey : identifying submillimeter continuum variability over several year timescales using archival JCMT Gould Belt Survey observations

Author: Aleks Scholz, Hyunju Yoo, Helen Kirk, Sarah Graves, Sung-ju Kang, Oscar Morata, Yuri Aikawa, Doug Johnstone, Geoffrey C. Bower, Graham S. Bell, Gregory J. Herczeg, Miju Kang, Wen Ping Chen, Jennifer Hatchell, James Lane, Satoko Takahashi, Peter Scicluna, Huei-Ru Vivien Chen, Andy Pon, Steve Mairs, Jeong-Eun Lee, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: Research program, Library science, FOS: Physical sciences, general [Submillimeter], 01 natural sciences, 010305 fluids & plasmas, pre-main sequence [Stars], 0103 physical sciences, QB Astronomy, East Asia, China, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), formation [Stars], QC, QB, Physics, geography, Summit, geography.geographical_feature_category, Joint Astronomy Centre, ISM [Submillimeter], Astronomy and Astrophysics, 3rd-DAS, Astrophysics - Astrophysics of Galaxies, Scholarship, QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Space Science, Catalogs, structure [ISM], Engineering research
Abstract: Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterised across the observable SED. In this study, we develop methods to robustly analyse repeated observations of an area of the sky for submillimetre variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare \mbox{850 $\mu$m} JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2-4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find 7 variable candidates, 5 of which we classify as \textit{Strong} and the remaining 2 as \textit{Extended} to indicate the latter are associated with larger-scale structure. For the \textit{Strong} variable candidates, we find an average fractional peak brightness change per year of |4.0|\% yr$^{-1}$ with a standard deviation of $2.7\%\mathrm{\:yr}^{-1}$. In total, 7\% of the protostars associated with \mbox{850 $\mu$m} emission in our sample show signs of variability. Four of the five \textit{Strong} sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the \mbox{850 $\mu$m} periodicity of the submillimetre variable source, EC 53, to be \mbox{567 $\pm$ 32 days} based on the archival Gould Belt Survey data., Comment: 33 Pages, 19 figures, Accepted in ApJ
Published: 2017

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

Author: Satoko Takahashi, Oscar Morata, Sarah Graves, Yuri Aikawa, Chang Won Lee, Jaehan Bae, Yi-Jehng Kuan, Ya-Wen Tang, Eun Jung Chung, Eduard I. Vorobiov, Helen Kirk, Shigehisa Takakuwa, Yuxin He, James Lane, Jonathan Williams, Miju Kang, Michael M. Dunham, Hyunju Yoo, Aleks Scholz, A-Ran Lyo, Manash R. Samal, Geoffrey C. Bower, Woojin Kwon, Gwanjeong Kim, Feng Long, Zhaohuan Zhu, Huei-Ru Vivien Chen, Peter Scicluna, Graham S. Bell, Mi-Ryang Kim, Lei Qian, Yiren Wang, S. P. S. Eyres, Lynne A. Hillenbrand, Bhavana Lalchand, Kevin Lacaille, Scott Chapman, Shu-ichiro Inutsuka, Emily Drabek-Maunder, Shih-Ping Lai, Archana Soam, Dimitris Stamatellos, Wen Ping Chen, Andy Pon, Steve Mairs, Sung-ju Kang, E’lisa M. Lee, Jeong-Eun Lee, Chin-Fei Lee, Jianjun Zhou, Harriet Parsons, Doug Johnstone, Hongchi Wang, Jan Forbrich, Kyoung Hee Kim, Gregory J. Herczeg, Jennifer Hatchell, Ramprasad Rao, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, stars [Submillimeter], F500, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Accretion rate, protostars [Stars], 0103 physical sciences, QB Astronomy, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), formation [Stars], QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, 3rd-DAS, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Wavelength, Stars, QC Physics, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, variables: T Tauri, Herbig Ae/Be [Stars]
Abstract: Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion -- prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase is almost entirely unconstrained. In "A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star Forming Regions", we are monitoring monthly with SCUBA-2 the sub-mm emission in eight fields within nearby (, ApJ, accepted
Published: 2017

16. Seeds of Life in Space (SOLIS): I. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4

Author: Rafael Bachiller, S. Spezzano, Jaime E. Pineda, Emmanuel Caux, Paola Caselli, Bertrand Lefloch, Piero Ugliengo, Yoko Oya, Audrey Coutens, Claudio Codella, Serena Viti, Claudine Kahane, Andy Pon, Jonathan Holdship, R. Neri, R. Choudhury, P. Hily-Blant, Patrice Theulé, Jacob C. Laas, Anton Vasyunin, Sandrine Bottinelli, A. Jaber Al-Edhari, Francesco Fontani, Izaskun Jiménez-Serra, Linda Podio, Felipe O. Alves, François Dulieu, Laurent Wiesenfeld, Cecilia Ceccarelli, D. Quénard, Satoshi Yamamoto, Cécile Favre, Ian R. Sims, Leonardo Testi, Vianney Taquet, Luca Bizzocchi, Nami Sakai, Ana López-Sepulcre, Albert Rimola, Nadia Balucani, E. Bianchi, Ana Chacón-Tanarro, Anna Punanova, Siyi Feng, C. Vastel, INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia (UNIPG), Università degli Studi di Firenze [Firenze], Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), University College of London [London] (UCL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona [Barcelona] (UAB), Queen Mary University of London (QMUL), University of Western Ontario (UWO), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Universiteit Leiden [Leiden], Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), Ural Federal University [Ekaterinburg] (UrFU), University of Electro-Communications [Tokyo] (UEC), Physique et Chimie du Milieu Interstellaire (PCMI) - Conseil National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales (CNES), LabeX Osug (Investissements d'avenir) [ANR10LABX56], Canadian Institute for Theoretical Astrophysics (CITA), European Research Council [PALs 320620], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Universitat Autònoma de Barcelona (UAB), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia = University of Perugia (UNIPG), Università degli Studi di Firenze = University of Florence (UniFI), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universiteit Leiden, and Università degli studi di Torino = University of Turin (UNITO)
Subjects: 010504 meteorology & atmospheric sciences, radio lines ISM, CHEMICAL MODEL, chemistry.chemical_element, Flux, Astrophysics, 01 natural sciences, 7. Clean energy, star formation, MOLECULES, ISM molecules, ABUNDANCE RATIOS, FORMATION [STARS], 0103 physical sciences, Cluster (physics), CHAINS, 010303 astronomy & astrophysics, INTERSTELLAR MEDIUMS, ComputingMilieux_MISCELLANEOUS, Radio lines: ISM, 0105 earth and related environmental sciences, Line (formation), Physics, [PHYS]Physics [physics], EASTERN REGIONS, ISM: Molecules, Stars: Formation, Astronomy and Astrophysics, Space and Planetary Science, IONISATION RATES, Star formation, ISM [RADIO LINES], COSMIC RAYS, Galaxy, Interstellar medium, Stars, chemistry, 13. Climate action, MOLECULES [ISM], COSMOLOGY, IONIZATION, Molecular physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Carbon, STARS
Abstract: The interstellar delivery of carbon atoms locked into molecules might be one of the key ingredients for the emergence of life. Cyanopolyynes are carbon chains delimited at their two extremities by an atom of hydrogen and a cyano group, meaning that they could be excellent reservoirs of carbon. The simplest member, HC3N, is ubiquitous in the galactic interstellar medium and found also in external galaxies. Thus, understanding the growth of cyanopolyynes in regions forming stars similar to our Sun, and what affects them, is particularly relevant. In the framework of the IRAM/NOEMA Large Program SOLIS (Seeds Of Life In Space), we have obtained a map of two cyanopolyynes, HC3N and HC5N, in the protocluster OMC-2 FIR4. Because our Sun is thought to be born in a rich cluster, OMC-2 FIR4 is one of the closest and best known representatives of the environment in which the Sun may have been born. We find a HC3N/HC5N abundance ratio across the source in the range 1..30, with the smallest values (≤10) in FIR5 and in the eastern region of FIR4. The ratios ≤10 can be reproduced by chemical models only if: (1) the cosmic-ray ionisation rate is ∼4× 10-14 s-1; (2) the gaseous elemental ratio C/O is close to unity; and (3) oxygen and carbon are largely depleted. The large is comparable to that measured in FIR4 by previous works and was interpreted as due to a flux of energetic (≥10 MeV) particles from embedded sources. We suggest that these sources could lie east of FIR4 and FIR5. A temperature gradient across FIR4, with T decreasing from east to west by about 10 K, could also explain the observed change in the HC3N/HC5N line ratio, without the need of a cosmic ray ionisation rate gradient. However, even in this case, a high constant cosmic-ray ionisation rate (of the order of 10s s-1) is necessary to reproduce the observations. © ESO 2017. European Research Council, ERC: PALs 320620 Centre National dâ Etudes Spatiales, CNES ANR10LABX56 Canadian Institute for Theoretical Astrophysics, ICAT Conseil National de la Recherche Scientifique, CNRS-L ★ Based on observations carried out under project number L15AA with the IRAM NOEMA Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). ★★ The final IRAM data used in the paper (FITS format) are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A57 Acknowledgements. We thank the IRAM staff for their help in the data reduction. Many thanks to the anonymous referee for his/her constructive comments. This work was supported by the French program Physique et Chimie du Milieu In-terstellaire (PCMI) funded by the Conseil National de la Recherche Scientifique (CNRS) and Centre National d’Études Spatiales (CNES), and by a grant from LabeX Osug@2020 (Investissements d’avenir – ANR10LABX56). Partial salary support for A. Pon was provided by a Canadian Institute for Theoretical Astrophysics (CITA) National Fellowship. P.C., A. Punanova, A.C., and J.E.P. acknowledge support from the European Research Council (project PALs 320620). C.F. acknowledges founding from French space agency CNES.
Published: 2017
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17. Seeds of Life in Space (SOLIS). II. Formamide in protostellar shocks: Evidence for gas-phase formation

Author: Izaskun Jiménez-Serra, Ana Chacón-Tanarro, Claudine Kahane, Andy Pon, R. Neri, Yoko Oya, Patrice Theulé, Leonardo Testi, Audrey Coutens, Paola Caselli, Charlotte Vastel, Serena Viti, François Dulieu, Jaime E. Pineda, R. Choudhury, P. Hily-Blant, J. Ospina, Fanny Vazart, Vincenzo Barone, Ana López-Sepulcre, Ian R. Sims, Laurent Wiesenfeld, Claudio Codella, Anna Punanova, Sandrine Bottinelli, Vianney Taquet, Francesco Fontani, Jacob C. Laas, A. Jaber Al-Edhari, Linda Podio, Cecilia Ceccarelli, Satoshi Yamamoto, Nami Sakai, Felipe O. Alves, Rafael Bachiller, Emmanuel Caux, S. Spezzano, D. Quénard, Nadia Balucani, Siyi Feng, Cécile Favre, Luca Bizzocchi, Cristina Puzzarini, Bertrand Lefloch, Piero Ugliengo, Anton Vasyunin, Jonathan Holdship, Dimitrios Skouteris, Albert Rimola, E. Bianchi, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Perugia (UNIPG), INAF - Osservatorio Astronomico di Brera (OAB), Southern University of Science and Technology [Shenzhen] (SUSTech), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Queen Mary University of London (QMUL), University College of London [London] (UCL), ESAB, Universitad polytecnica de Cataluna, University of Western Ontario (UWO), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), departament de Quimica, Universitat Autònoma de Barcelona [Barcelona] (UAB), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Scuola Normale Superiore di Pisa (SNS), European Southern Observatory (ESO), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), Codella, C., Ceccarelli, C., Caselli, P., Balucani, N., Barone, V., Fontani, F., Lefloch, B., Podio, L., Viti, S., Feng, S., Bachiller, R., Bianchi, E., Dulieu, F., Jiménez-Serra, I., Holdship, J., Neri, R., Pineda, J.E., Pon, A., Sims, I., Spezzano, S., Vasyunin, A.I., Alves, F., Bizzocchi, L., Bottinelli, S., Caux, E., Chacón-Tanarro, A., Choudhury, R., Coutens, A., Favre, C., Hily-Blant, P., Kahane, C., Jaber Al-Edhari, A., Laas, J., López-Sepulcre, A., Ospina, J., Oya, Y., Punanova, A., Puzzarini, C., Quenard, D., Rimola, A., Sakai, N., Skouteris, D., Taquet, V., Testi, L., Theulé, P., Ugliengo, P., Vastel, C., Vazart, F., Wiesenfeld, L., Yamamoto, S., Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Università degli Studi di Perugia = University of Perugia (UNIPG), Southern University of Science and Technology (SUSTech), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona (UAB), Università degli studi di Torino = University of Turin (UNITO), Pineda, J. E., Vasyunin, A. I., Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
Subjects: Formamide, Abundance (chemistry), Direct evidence, Stars: formation, FOS: Physical sciences, Context (language use), Astrophysics, ISM: molecule, 01 natural sciences, chemistry.chemical_compound, 0103 physical sciences, Protostar, molecule [ISM], 010303 astronomy & astrophysics, ISM: jets and outflow, formation [Stars], ComputingMilieux_MISCELLANEOUS, Line (formation), Earth and Planetary Astrophysics (astro-ph.EP), ISM: individual objects: L1157-B1, ISM: jets and outflows, ISM: molecules, Astronomy and Astrophysics, Space and Planetary Science, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, jets and outflow [ISM], individual objects: L1157-B1 [ISM], Astronomy and Astrophysic, Stars, chemistry, Millimeter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Context: Modern versions of the Miller-Urey experiment claim that formamide (NH$_2$CHO) could be the starting point for the formation of metabolic and genetic macromolecules. Intriguingly, formamide is indeed observed in regions forming Solar-type stars as well as in external galaxies. Aims: How NH$_2$CHO is formed has been a puzzle for decades: our goal is to contribute to the hotly debated question of whether formamide is mostly formed via gas-phase or grain surface chemistry. Methods: We used the NOEMA interferometer to image NH$_2$CHO towards the L1157-B1 blue-shifted shock, a well known interstellar laboratory, to study how the components of dust mantles and cores released into the gas phase triggers the formation of formamide. Results: We report the first spatially resolved image (size $\sim$ 9", $\sim$ 2300 AU) of formamide emission in a shocked region around a Sun-like protostar: the line profiles are blueshifted and have a FWHM $\simeq$ 5 km s$^{-1}$. A column density of $N_{\rm NH_2CHO}$ = 8 $\times$ 10$^{12}$ cm$^{-1}$, and an abundance (with respect to H-nuclei) of 4 $\times$ 10$^{-9}$ are derived. We show a spatial segregation of formamide with respect to other organic species. Our observations, coupled with a chemical modelling analysis, indicate that the formamide observed in L1157-B1 is formed by gas-phase chemical process, and not on grain surfaces as previously suggested. Conclusions: The SOLIS interferometric observations of formamide provide direct evidence that this potentially crucial brick of life is efficiently formed in the gas-phase around Sun-like protostars., 7 pages, 1 table, 5 figures, A&A Letters, in press
Published: 2017
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18. Seeds Of Life In Space (SOLIS): The Organic Composition Diversity at 300-1000 au Scale in Solar-type Star-forming Regions

Author: R. Choudhury, Emmanuel Caux, Felipe O. Alves, Jacob C. Laas, Albert Rimola, François Dulieu, Satoshi Yamamoto, Charlotte Vastel, Francesco Fontani, Serena Viti, Anton Vasyunin, Leonardo Testi, E. Bianchi, Jonathan Holdship, Ana Chacón-Tanarro, Nami Sakai, P. Hily-Blant, J. Ospina, Sandrine Bottinelli, Claudine Kahane, Andy Pon, D. Quénard, Bertrand Lefloch, Piero Ugliengo, Laurent Wiesenfeld, Ana López-Sepulcre, R. Neri, Rafael Bachiller, Cecilia Ceccarelli, Jaime E. Pineda, Claudio Codella, Vianney Taquet, Cécile Favre, Paola Caselli, Anna Punanova, A. Jaber Al-Edhari, Patrice Theulé, Linda Podio, S. Spezzano, Luca Bizzocchi, Yoko Oya, Audrey Coutens, Siyi Feng, Nadia Balucani, Ian R. Sims, Izaskun Jiménez-Serra, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astrofisico di Arcetri (OAA), Queen Mary University of London (QMUL), University College of London [London] (UCL), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia (UNIPG), Università degli Studi di Firenze [Firenze], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Western Ontario (UWO), Universitat Autònoma de Barcelona [Barcelona] (UAB), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), Ural Federal University [Ekaterinburg] (UrFU), Centre National de la Recherche Scientifique (CNRS), University of Electro-Communications [Tokyo] (UEC), European Research Council (ERC) [320620, 741002], French program Physique et Chimie du Milieu Interstellaire (PCMI) - Conseil National de la Recherche Scientifique (CNRS), Centre National dEtudes Spatiales (CNES), Italian Ministero dell'Istruzione, Universita e Ricerca, through the grant Progetti Premiali iALMA [CUP C52I13000140001], Canadian Institute for Theoretical Astrophysics (CITA) National Fellowship, STFC [ST/L004801, ST/M004139], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia = University of Perugia (UNIPG), Università degli Studi di Firenze = University of Florence (UniFI), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona (UAB), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Max-Planck-Institut fur Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching, Germany, INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), Institut de RadioAstronomie Millimétrique (IRAM), Department of Physics and Astronomy, University College London, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Observatorio Astronómico Nacional, Observatorio de Madrid, Alfonso XII (OAN), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Molécules dans l'Univers, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA (UMR_8112)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), University of AL-Muthanna, College of Science, Physics Department, AL-Muthanna, Iraq, Department of Physics, University of Tokyo, Departament de Quimica, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Spain, RIKEN The Institute of Physical and Chemical Research, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: radio lines ISM, FOS: Physical sciences, Scale (descriptive set theory), Astrophysics, Type (model theory), Star (graph theory), Space (mathematics), ISM: clouds, 01 natural sciences, ISM: abundances, Spectral line, ISM molecules, Abundance (ecology), ISM: molecules, radio lines: ISM, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, 14. Life underwater, 010303 astronomy & astrophysics, ISM abundances, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, ISM clouds, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Astrophysics of Galaxies (astro-ph.GA), Molecular physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Order of magnitude
Abstract: Complex organic molecules have been observed for decades in the interstellar medium. Some of them might be considered as small bricks of the macromolecules at the base of terrestrial life. It is hence particularly important to understand organic chemistry in Solar-like star forming regions. In this article, we present a new observational project: SOLIS (Seeds Of Life In Space). This is a Large Project at the IRAM-NOEMA interferometer, and its scope is to image the emission of several crucial organic molecules in a sample of Solar-like star forming regions in different evolutionary stage and environments. Here, we report the first SOLIS results, obtained from analysing the spectra of different regions of the Class 0 source NGC1333-IRAS4A, the protocluster OMC-2 FIR4, and the shock site L1157-B1. The different regions were identified based on the images of formamide (NH2CHO) and cyanodiacetylene (HC5N) lines. We discuss the observed large diversity in the molecular and organic content, both on large (3000-10000 au) and relatively small (300-1000 au) scales. Finally, we derive upper limits to the methoxy fractional abundance in the three observed regions of the same order of magnitude of that measured in few cold prestellar objects, namely ~10^-12-10^-11 with respect to H2 molecules., Comment: Accepted for publication on The Astrophysical Journal
Published: 2017
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19. Mid-J CO observations of Perseus B1-East 5: evidence for turbulent dissipation via low-velocity shocks

Author: Andy Pon, Doug Johnstone, Michael J. Kaufman, Paola Caselli, and René Plume
Subjects: 13. Climate action, 010308 nuclear & particles physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 7. Clean energy, 010303 astronomy & astrophysics, 01 natural sciences, Astrophysics::Galaxy Astrophysics
Abstract: Giant molecular clouds contain supersonic turbulence and magnetohydrodynamic simulations predict that this turbulence should decay rapidly. Such turbulent dissipation has the potential to create a warm (T ~100 K) gas component within a molecular cloud. We present observations of the CO J = 5-4 and 6-5 transitions, taken with the Herschel Space Observatory, towards the Perseus B1-East 5 region. We combine these new observations with archival measurements of lower rotational transitions and fit photodissociation region models to the data. We show that Perseus B1-E5 has an anomalously large CO J = 6-5 integrated intensity, consistent with a warm gas component existing within the region. This excess emission is consistent with predictions for shock heating due to the dissipation of turbulence in low velocity shocks with the shocks having a volume filling factor of 0.15 per cent. We find that B1-E has a turbulent energy dissipation rate of 3.5 x 10$^{32}$ erg / s and a dissipation time-scale that is only a factor of 3 larger than the flow crossing time-scale., 18 pages, 15 figures, 4 tables, accepted by MNRAS, fixed errors described in erratum
Published: 2014
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20. Kompaneets model fitting of the Orion–Eridanus superbubble

Author: Andy Pon, Doug Johnstone, John Bally, and Carl Heiles
Subjects: Physics, 010308 nuclear & particles physics, Molecular cloud, FOS: Physical sciences, Model fitting, Astronomy, Astronomy and Astrophysics, Superbubble, Astrophysics, Galactic plane, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Orion–Eridanus Superbubble, Interstellar medium, Supernova, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Eridanus, 010303 astronomy & astrophysics
Abstract: Winds and supernovae from OB associations create large cavities in the interstellar medium referred to as superbubbles. The Orion molecular clouds are the nearest high mass star-forming region and have created a highly elongated, 20 degree x 45 degree, superbubble. We fit Kompaneets models to the Orion-Eridanus superbubble and find that a model where the Eridanus side of the superbubble is oriented away from the Sun provides a marginal fit. Because this model requires an unusually small scaleheight of 40 pc and has the superbubble inclined 35 degrees from the normal to the Galactic plane, we propose that this model should be treated as a general framework for modelling the Orion-Eridanus superbubble, with a secondary physical mechanism not included in the Kompaneets model required to fully account for the orientation and elongation of the superbubble., Comment: 15 pages, 5 figures, 2 tables, accepted by MNRAS, minor grammatical changes
Published: 2014
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21. KOMPANEETS MODEL FITTING of the ORION-ERIDANUS SUPERBUBBLE. II. THINKING OUTSIDE of BARNARD'S LOOP

Author: João Alves, Bram B. Ochsendorf, Alexander G. G. M. Tielens, Andy Pon, Shantanu Basu, and John Bally
Subjects: Physics, 010504 meteorology & atmospheric sciences, individual objects (Orion-Eridanus Superbubble) [ISM], FOS: Physical sciences, Model fitting, Astronomy and Astrophysics, Superbubble, Astrophysics, 01 natural sciences, Orion–Eridanus Superbubble, Astrophysics - Astrophysics of Galaxies, bubbles [ISM], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Eridanus, Disc, structure-stars: formation [ISM], 010303 astronomy & astrophysics, disk [Galaxy], 0105 earth and related environmental sciences
Abstract: The Orion star-forming region is the nearest active high-mass star-forming region and has created a large superbubble, the Orion-Eridanus superbubble. Recent work by Ochsendorf et al. has extended the accepted boundary of the superbubble. We fit Kompaneets models of superbubbles expanding in exponential atmospheres to the new, larger shape of the Orion-Eridanus superbubble. We find that this larger morphology of the superbubble is consistent with the evolution of the superbubble being primarily controlled by expansion into the exponential Galactic disk ISM if the superbubble is oriented with the Eridanus side farther from the Sun than the Orion side. Unlike previous Kompaneets model fits that required abnormally small scale heights for the Galactic disk (, 8 pages, 3 figures, accepted by ApJ, minor grammatical changes
Published: 2016

22. Mid-J CO Shock Tracing Observations of Infrared Dark Clouds. III. SLED Fitting

Author: M. J. Butler, Andy Pon, Paola Caselli, Francesco Fontani, Doug Johnstone, Izaskun Jiménez-Serra, Jonathan C. Tan, Michael J. Kaufman, and A. Palau
Subjects: Shock wave, Physics, 010308 nuclear & particles physics, Infrared, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Photodissociation region, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Spectral line, Stars, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, 010303 astronomy & astrophysics, Line (formation)
Abstract: Giant molecular clouds contain supersonic turbulence that can locally heat small fractions of gas to over 100 K. We run shock models for low-velocity, C-type shocks propagating into gas with densities between 10^3 and 10^5 cm^(-3) and find that CO lines are the most important cooling lines. Comparison to photodissociation region (PDR) models indicates that mid-J CO lines (J = 8-7 and higher) should be dominated by emission from shocked gas. In Papers I and II we presented CO J = 3-2, 8-7, and 9-8 observations toward four primarily quiescent clumps within infrared dark clouds. Here we fit PDR models to the combined spectral line energy distributions and show that the PDR models that best fit the low-J CO emission underpredict the mid-J CO emission by orders of magnitude, strongly hinting at a hot gas component within these clumps. The low-J CO data clearly show that the integrated intensities of both the CO J = 8-7 and 9-8 lines are anomalously high, such that the line ratio can be used to characterize the hot gas component. Shock models are reasonably consistent with the observed mid-J CO emission, with models with densities near 10^(4.5) cm^(-3) providing the best agreement. Where this mid-J CO is detected, the mean volume filling factor of the hot gas is 0.1%. Much of the observed mid-J CO emission, however, is also associated with known protostars and may be due to protostellar feedback., Comment: 28 pages, 18 figures, accepted by ApJ, grammatical and typesetting corrections
Published: 2016

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

Author: Satoko Takahashi, Wen Ping Chen, Jennifer Hatchell, Geoffrey C. Bower, Graham S. Bell, Miju Kang, Helen Kirk, Hyunju Yoo, Huei-Ru Vivien Chen, Sarah Graves, Peter Scicluna, Gregory J. Herczeg, James Lane, Aleks Scholz, Doug Johnstone, Jeong-Eun Lee, Sung-ju Kang, Andy Pon, Steve Mairs, Oscar Morata, Yuri Aikawa, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: Physics, Data collection, 010308 nuclear & particles physics, NDAS, Library science, Astronomy and Astrophysics, star formation [Galaxies], 01 natural sciences, Chinese academy of sciences, QC Physics, 13. Climate action, Space and Planetary Science, Research council, Observatory, protostars [Stars], 0103 physical sciences, Agency (sociology), QB Astronomy, East Asia, Space Science, China, 010303 astronomy & astrophysics, QC, QB
Abstract: We analyze results from the first 18 months of monthly submillimeter monitoring of eight star-forming regions in the JCMT Transient Survey. In our search for stochastic variability in 1643 bright peaks, only the previously identified source, EC 53, shows behavior well above the expected measurement uncertainty. Another four sources—two disks and two protostars—show moderately enhanced standard deviations in brightness, as expected for stochastic variables. For the two protostars, this apparent variability is the result of single epochs that are much brighter than the mean. In our search for secular brightness variations that are linear in time, we measure the fractional brightness change per year for 150 bright peaks, 50 of which are protostellar. The ensemble distribution of slopes is well fit by a normal distribution with σ ~ 0.023. Most sources are not rapidly brightening or fading at submillimeter wavelengths. Comparison against time-randomized realizations shows that the width of the distribution is dominated by the uncertainty in the individual brightness measurements of the sources. A toy model for secular variability reveals that an underlying Gaussian distribution of linear fractional brightness change σ = 0.005 would be unobservable in the present sample, whereas an underlying distribution with σ = 0.02 is ruled out. Five protostellar sources, 10% of the protostellar sample, are found to have robust secular measures deviating from a constant flux. The sensitivity to secular brightness variations will improve significantly with a sample over a longer time duration, with an improvement by factor of two expected by the conclusion of our 36 month survey. Publisher PDF
Published: 2018
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24. Deuterium Fractionation in the Ophiuchus Molecular Cloud

Author: Arnaud Belloche, Paola Caselli, Andy Pon, Philippe André, Anna Punanova, Max-Planck-Institut für Extraterrestrische Physik (MPE), University of Western Ontario (UWO), Max-Planck-Institut für Radioastronomie (MPIFR), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Project: 320620,EC:FP7:ERC,ERC-2012-ADG_20120216,PALS(2013), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: Interstellar cloud, FOS: Physical sciences, Astrophysics, Fractionation, 01 natural sciences, ISM: clouds, ISM: abundances, TRACER, 0103 physical sciences, Thermal, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, ISM: kinematics and dynamics, stars: formation, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Deuterium, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ophiuchus, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. We measure the deuterium fraction, RD, and the CO-depletion factor, fd, toward a number of starless and protostellar cores in the L1688 region of the Ophiuchus molecular cloud complex and search for variations based upon environmental differences across L1688. The kinematic properties of the dense gas traced by the N2H+ and N2D+ (1-0) lines are also discussed. Methods. RD has been measured via observations of the J=1-0 transition of N2H+ and N2D+ toward 33 dense cores in different regions of L1688. fd estimates have been done using C17O(1-0) and 850 micron dust continuum emission from the SCUBA survey. All line observations were carried out with the IRAM 30 meter antenna. Results. The dense cores show large (2-40%) deuterium fractions, with significant variations between the sub-regions of L1688. The CO-depletion factor also varies from one region to another (1-7). Two different correlations are found between deuterium fraction and CO-depletion factor: cores in regions A, B2 and I show increasing RD with increasing fd, similar to previous studies of deuterium fraction in pre-stellar cores; cores in regions B1, B1B2, C, E, F and H show a steeper RD-fd correlation, with large deuterium fractions occurring in fairly quiescent gas with relatively low CO freeze-out factors. These are probably recently formed, centrally concentrated starless cores which have not yet started the contraction phase toward protostellar formation. We also find that the deuterium fraction is affected by the amount of turbulence, dust temperature and distance from heating sources in all regions of L1688, although no clear trend is found., Comment: 22 pages, 14 figures, accepted for publication in A&A
Published: 2015
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25. The Origin of Ionized Filaments Within the Orion-Eridanus Superbubble

Author: Andy Pon, Carl Heiles, Doug Johnstone, and John Bally
Subjects: Physics, Line-of-sight, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Superbubble, Astrophysics, ISM: individual objects: Eridanus filments, Orion–Eridanus Superbubble, Astrophysics - Astrophysics of Galaxies, ISM: individual objects: Orion-Eridanus superbubble, Space and Planetary Science, ISM: cloud, Ionization, Astrophysics of Galaxies (astro-ph.GA), High mass, ISM: structu, Eridanus, ISM: bubble
Abstract: The Orion-Eridanus superbubble, formed by the nearby Orion high mass star-forming region, contains multiple bright H$\alpha$ filaments on the Eridanus side of the superbubble. We examine the implications of the H$\alpha$ brightnesses and sizes of these filaments, the Eridanus filaments. We find that either the filaments must be highly elongated along the line of sight or they cannot be equilibrium structures illuminated solely by the Orion star-forming region. The Eridanus filaments may, instead, have formed when the Orion-Eridanus superbubble encountered and compressed a pre-existing, ionized gas cloud, such that the filaments are now out of equilibrium and slowly recombining., Comment: 11 pages, 2 figures, accepted by MNRAS, minor grammatical changes
Published: 2014

26. Mid-JCO shock tracing observations of infrared dark clouds

Author: Izaskun Jiménez-Serra, Andy Pon, M. J. Butler, Francesco Fontani, A. Palau, Paola Caselli, Michael J. Kaufman, Jonathan C. Tan, and Doug Johnstone
Subjects: Physics, Shock (fluid dynamics), 010308 nuclear & particles physics, Star formation, Infrared, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Kinematics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Interstellar medium, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Excitation
Abstract: Infrared dark clouds are kinematically complex molecular structures in the interstellar medium that can host sites of massive star formation. We present 4 square arcminute maps of the 12CO, 13CO, and C18O J = 3 to 2 lines from selected locations within the C and F (G028.37+00.07 and G034.43+00.24) infrared dark clouds (IRDCs), as well as single pointing observations of the 13CO and C18O J = 2 to 1 lines towards three cores within these clouds. We derive CO gas temperatures throughout the maps and find that CO is significantly frozen out within these IRDCs. We find that the CO depletion tends to be the highest near column density peaks, with maximum depletion factors between 5 and 9 in IRDC F and between 16 and 31 in IRDC C. We also detect multiple velocity components and complex kinematic structure in both IRDCs. Therefore, the kinematics of IRDCs seem to point to dynamically evolving structures yielding dense cores with considerable depletion factors., Comment: 23 pages, 20 figures, accepted by A&A
Published: 2016
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27. Modes of Star Formation in Finite Molecular Clouds

Author: Doug Johnstone, Fabian Heitsch, and Andy Pon
Subjects: Physics, stars: formation, 010308 nuclear & particles physics, Star formation, ISM: structure, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Mechanics, Astrophysics - Astrophysics of Galaxies, ISM: clouds, 01 natural sciences, Instability, Gravitation, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, SPHERES, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: We analytically investigate the modes of gravity-induced star formation possible in idealized finite molecular clouds where global collapse competes against both local Jeans instabilities and discontinuous edge instabilities. We examine these timescales for collapse in spheres, discs, and cylinders, with emphasis on the structure, size, and degree of internal perturbations required in order for local collapse to occur before global collapse. We find that internal, local collapse is more effective for the lower dimensional objects. Spheres and discs, if unsupported against global collapse, must either contain strong perturbations or must be unrealistically large in order for small density perturbations to collapse significantly faster than the entire cloud. We find, on the other hand, that filamentary geometry is the most favorable situation for the smallest perturbations to grow before global collapse overwhelms them and that filaments containing only a few Jeans masses and weak density perturbations can readily fragment. These idealized solutions are compared with simulations of star-forming regions in an attempt to delineate the role of global, local, and edge instabilities in determining the fragmentation properties of molecular clouds. The combined results are also discussed in the context of recent observations of Galactic molecular clouds., Comment: 42 pages, 6 figures, 1 table, accepted by ApJ
Published: 2011
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28. Erratum: Mid-J CO observations of Perseus B1-East 5: evidence for turbulent dissipation via low-velocity shocks

Author: Doug Johnstone, Paola Caselli, Michael J. Kaufman, Rene Plume, and Andy Pon
Subjects: Physics, Shock wave, Shock (fluid dynamics), Space and Planetary Science, Turbulence, Molecular cloud, Astronomy and Astrophysics, Supersonic speed, Magnetohydrodynamic drive, Astrophysics, Dissipation, Photodissociation region, Astrophysics::Galaxy Astrophysics
Abstract: Giant molecular clouds contain supersonic turbulence and magnetohydrodynamic simulations predict that this turbulence should decay rapidly. Such turbulent dissipation has the potential to create a warm (T ~100 K) gas component within a molecular cloud. We present observations of the CO J = 5-4 and 6-5 transitions, taken with the Herschel Space Observatory, towards the Perseus B1-East 5 region. We combine these new observations with archival measurements of lower rotational transitions and fit photodissociation region models to the data. We show that Perseus B1-E5 has an anomalously large CO J = 6-5 integrated intensity, consistent with a warm gas component existing within the region. This excess emission is consistent with predictions for shock heating due to the dissipation of turbulence in low velocity shocks with the shocks having a volume filling factor of 0.15 per cent. We find that B1-E has a turbulent energy dissipation rate of 3.5 x 10$^{32}$ erg / s and a dissipation time-scale that is only a factor of 3 larger than the flow crossing time-scale.
Published: 2015
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29. CORRELATING INFALL WITH DEUTERIUM FRACTIONATION IN DENSE CORES

Author: Scott Schnee, James Di Francesco, Paola Caselli, Doug Johnstone, Rachel Friesen, Nathan Brunetti, and Andy Pon
Subjects: 010504 meteorology & atmospheric sciences, Hydrogen, FOS: Physical sciences, chemistry.chemical_element, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, Ion, Speed of sound, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Protostar, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Charged particle, Stars, Astrophysics - Solar and Stellar Astrophysics, Deuterium, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract: We present a survey of HCO+ (3-2) observations pointed towards dense cores with previous measurements of N(N2D+)/N(N2H+). Of the 26 cores in this survey, five show the spectroscopic signature of outward motion, nine exhibit neither inward nor outward motion, eleven appear to be infalling, and one is not detected. We compare the degree of deuterium fractionation with infall velocities calculated from the HCO+ spectra and find that those cores with [D]/[H] > 0.1 are more likely to have the signature of inward motions than cores with smaller [D]/[H] ratios. Infall motions are also much more common in cores with masses exceeding their thermal Jeans masses. The fastest infall velocity measured belongs to one of the two protostellar cores in our survey, L1521F, and the observed motions are typically on the order of the sound speed., Accepted to ApJ
Published: 2013
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30. A First Look at BISTRO Observations of the ρ Oph-A core.

Author: Jungmi Kwon, Yasuo Doi, Motohide Tamura, Masafumi Matsumura, Kate Pattle, David Berry, Sarah Sadavoy, Brenda C. Matthews, Derek Ward-Thompson, Tetsuo Hasegawa, Ray S. Furuya, Andy Pon, James Di Francesco, Doris Arzoumanian, Saeko S. Hayashi, Koji S. Kawabata, Takashi Onaka, Minho Choi, Miju Kang, and Thiem Hoang
Subjects: STARS, BOLOMETERS, MAGNETIC fields, GALAXIES, INFRARED detectors
Abstract: We present 850 μm imaging polarimetry data of the ρ 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, -fields In STar forming RegiOns (BISTRO). 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 ρ Oph-A core; some of them can be part of a coherent magnetic field structure in the ρ Oph region. The results are consistent with previous observations of the brightest regions of ρ Oph-A, where the degrees of polarization are at a level of a few percent, 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 that are consistent at near-infrared and submillimeter wavelengths. Using the Davis–Chandrasekhar–Fermi method, we also derive magnetic field strengths in several subcore regions, which range from approximately 0.2 to 5 mG. We also find a correlation between the magnetic field orientations projected on the sky and the core centroid velocity components. [ABSTRACT FROM AUTHOR]
Published: 2018
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31. Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544.

Author: Anna Punanova, Paola Caselli, Siyi Feng, Ana Chacón-Tanarro, Cecilia Ceccarelli, Roberto Neri, Francesco Fontani, Izaskun Jiménez-Serra, Charlotte Vastel, Luca Bizzocchi, Andy Pon, Anton I. Vasyunin, Silvia Spezzano, Pierre Hily-Blant, Leonardo Testi, Serena Viti, Satoshi Yamamoto, Felipe Alves, Rafael Bachiller, and Nadia Balucani
Subjects: CENTROIDAL Voronoi tessellations, METHANOL, SUBSONIC flow, FLOW velocity, LOCAL thermodynamic equilibrium
Abstract: Toward the prestellar core L1544, the methanol (CH3OH) emission forms an asymmetric ring around the core center, where CH3OH is mostly in solid form, with a clear peak at 4000 au to the northeast of the dust continuum peak. As part of the NOEMA Large Project SOLIS (Seeds of Life in Space), the CH3OH peak has been spatially resolved to study its kinematics and physical structure and to investigate the cause behind the local enhancement. We find that methanol emission is distributed in a ridge parallel to the main axis of the dense core. The centroid velocity increases by about 0.2 km s−1 and the velocity dispersion increases from subsonic to transonic toward the central zone of the core, where the velocity field also shows complex structure. This could be an indication of gentle accretion of material onto the core or the interaction of two filaments, producing a slow shock. We measure the rotational temperature and show that methanol is in local thermodynamic equilibrium (LTE) only close to the dust peak, where it is significantly depleted. The CH3OH column density, Ntot(CH3OH), profile has been derived with non-LTE radiative transfer modeling and compared with chemical models of a static core. The measured Ntot(CH3OH) profile is consistent with model predictions, but the total column densities are one order of magnitude lower than those predicted by models, suggesting that the efficiency of reactive desorption or atomic hydrogen tunneling adopted in the model may be overestimated; or that an evolutionary model is needed to better reproduce methanol abundance. [ABSTRACT FROM AUTHOR]
Published: 2018
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32. The JCMT Transient Survey: Stochastic and Secular Variability of Protostars and Disks In the Submillimeter Region Observed over 18 Months.

Author: Doug Johnstone, Gregory J. Herczeg, Steve Mairs, Jennifer Hatchell, Geoffrey C. Bower, Helen Kirk, James Lane, Graham S. Bell, Sarah Graves, Yuri Aikawa, Huei-Ru Vivien Chen, Wen-Ping Chen, Miju Kang, Sung-Ju Kang, Jeong-Eun Lee, Oscar Morata, Andy Pon, Peter Scicluna, Aleks Scholz, and Satoko Takahashi
Subjects: PROTOSTARS, DISKS (Astrophysics), STOCHASTIC analysis, STAR formation, STANDARD deviations, RANDOM variables
Abstract: We analyze results from the first 18 months of monthly submillimeter monitoring of eight star-forming regions in the JCMT Transient Survey. In our search for stochastic variability in 1643 bright peaks, only the previously identified source, EC 53, shows behavior well above the expected measurement uncertainty. Another four sources—two disks and two protostars—show moderately enhanced standard deviations in brightness, as expected for stochastic variables. For the two protostars, this apparent variability is the result of single epochs that are much brighter than the mean. In our search for secular brightness variations that are linear in time, we measure the fractional brightness change per year for 150 bright peaks, 50 of which are protostellar. The ensemble distribution of slopes is well fit by a normal distribution with σ ∼ 0.023. Most sources are not rapidly brightening or fading at submillimeter wavelengths. Comparison against time-randomized realizations shows that the width of the distribution is dominated by the uncertainty in the individual brightness measurements of the sources. A toy model for secular variability reveals that an underlying Gaussian distribution of linear fractional brightness change σ = 0.005 would be unobservable in the present sample, whereas an underlying distribution with σ = 0.02 is ruled out. Five protostellar sources, 10% of the protostellar sample, are found to have robust secular measures deviating from a constant flux. The sensitivity to secular brightness variations will improve significantly with a sample over a longer time duration, with an improvement by factor of two expected by the conclusion of our 36 month survey. [ABSTRACT FROM AUTHOR]
Published: 2018
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33. The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations.

Author: Steve Mairs, Doug Johnstone, Helen Kirk, James Lane, Graham S. Bell, Sarah Graves, Gregory J. Herczeg, Peter Scicluna, Geoffrey C. Bower, Huei-Ru Vivien Chen, Jennifer Hatchell, Yuri Aikawa, Wen-Ping Chen, Miju Kang, Sung-Ju Kang, Jeong-Eun Lee, Oscar Morata, Andy Pon, Aleks Scholz, and Satoko Takahashi
Subjects: STAR formation, PROTOSTARS, STELLAR mass, ACCRETION (Astrophysics), STANDARD deviations
Abstract: Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterized across the observable SED. In this study, we develop methods to robustly analyze repeated observations of an area of the sky for submillimeter variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare 850 μm JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2–4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find seven variable candidates, five of which we classify as Strong, and the remaining two we classify as Extended to indicate that the latter are associated with larger-scale structure. For the Strong variable candidates, we find an average fractional peak brightness change per year of , with a standard deviation of . In total, 7% of the protostars associated with 850 μm emission in our sample show signs of variability. Four of the five Strong sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the 850 μm periodicity of the submillimeter variable source, EC 53, to be 567 ± 32 days, based on the archival Gould Belt Survey data. [ABSTRACT FROM AUTHOR]
Published: 2017
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34. The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament.

Author: Kate Pattle, Derek Ward-Thompson, David Berry, Jennifer Hatchell, Huei-Ru Chen, Andy Pon, Patrick M. Koch, Woojin Kwon, Jongsoo Kim, Pierre Bastien, Jungyeon Cho, Simon Coudé, James Di Francesco, Gary Fuller, Ray S. Furuya, Sarah F. Graves, Doug Johnstone, Jason Kirk, Jungmi Kwon, and Chang Won Lee
Subjects: ENERGY density, MAGNETIC fields, ORION (Constellation), ELECTROMAGNETIC theory, FRAGMENTATION reactions
Abstract: We determine the magnetic field strength in the OMC 1 region of the Orion A filament via a new implementation of the Chandrasekhar–Fermi method using observations performed as part of the James Clerk Maxwell Telescope (JCMT) B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. We combine BISTRO data with archival SCUBA-2 and HARP observations to find a plane-of-sky magnetic field strength in OMC 1 of mG, where mG represents a predominantly systematic uncertainty. We develop a new method for measuring angular dispersion, analogous to unsharp masking. We find a magnetic energy density of J m−3 in OMC 1, comparable both to the gravitational potential energy density of OMC 1 (∼10−7 J m−3) and to the energy density in the Orion BN/KL outflow (∼10−7 J m−3). We find that neither the Alfvén velocity in OMC 1 nor the velocity of the super-Alfvénic outflow ejecta is sufficiently large for the BN/KL outflow to have caused large-scale distortion of the local magnetic field in the ∼500 yr lifetime of the outflow. Hence, we propose that the hourglass field morphology in OMC 1 is caused by the distortion of a primordial cylindrically symmetric magnetic field by the gravitational fragmentation of the filament and/or the gravitational interaction of the BN/KL and S clumps. We find that OMC 1 is currently in or near magnetically supported equilibrium, and that the current large-scale morphology of the BN/KL outflow is regulated by the geometry of the magnetic field in OMC 1, and not vice versa. [ABSTRACT FROM AUTHOR]
Published: 2017
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35. KOMPANEETS MODEL FITTING OF THE ORION–ERIDANUS SUPERBUBBLE. II. THINKING OUTSIDE OF BARNARD’S LOOP.

Author: Andy Pon, Bram B. Ochsendorf, João Alves, John Bally, Shantanu Basu, and Alexander G. G. M. Tielens
Subjects: *GALACTIC dynamics, *DISK galaxies, *ORION Nebula, *ORION (Constellation), *ATMOSPHERE
Abstract: The Orion star-forming region is the nearest active high-mass star-forming region and has created a large superbubble, the Orion–Eridanus superbubble. Recent work by Ochsendorf et al. has extended the accepted boundary of the superbubble. We fit Kompaneets models of superbubbles expanding in exponential atmospheres to the new larger shape of the Orion–Eridanus superbubble. We find that this larger morphology of the superbubble is consistent with the evolution of the superbubble being primarily controlled by expansion into the exponential Galactic disk ISM if the superbubble is oriented with the Eridanus side farther from the Sun than the Orion side. Unlike previous Kompaneets model fits that required abnormally small scale heights for the Galactic disk (<40 pc), we find morphologically consistent models with scale heights of 80 pc, similar to that expected for the Galactic disk. [ABSTRACT FROM AUTHOR]
Published: 2016
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35 results on '"Andy Pon"'

1. Benchmarked RADARSAT-2, SENTINEL-1 and RADARSAT Constellation Mission Change-Detection Monitoring at North Slide, Thompson River Valley, British Columbia: ensuring a Landslide-Resilient National Railway Network

2. Benchmarked RADARSAT-2, SENTINEL-1 and RADARSAT Constellation Mission Change-Detection Monitoring at North Slide, Thompson River Valley, British Columbia: ensuring a Landslide-Resilient National Railway Network

3. The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming Region

4. The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars

5. Brumadinho Dam InSAR study: analysis of TerraSAR-X, COSMO-SkyMed and Sentinel-1 images preceding the collapse

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

7. ALMA detections of the youngest protostars in Ophiuchus

8. A First Look at BISTRO Observations of The $\rho$ Oph-A core

9. Similar complex kinematics within two massive, filamentary infrared dark clouds

10. The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

11. Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544

12. Magnetic fields towards Ophiuchus-b derived from scuba-2 polarization measurements

13. Widespread SiO and CH3OH Emission in Filamentary Infrared-Dark Clouds★

14. The JCMT Transient Survey : identifying submillimeter continuum variability over several year timescales using archival JCMT Gould Belt Survey observations

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

16. Seeds of Life in Space (SOLIS): I. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4

17. Seeds of Life in Space (SOLIS). II. Formamide in protostellar shocks: Evidence for gas-phase formation

18. Seeds Of Life In Space (SOLIS): The Organic Composition Diversity at 300-1000 au Scale in Solar-type Star-forming Regions

19. Mid-J CO observations of Perseus B1-East 5: evidence for turbulent dissipation via low-velocity shocks

20. Kompaneets model fitting of the Orion–Eridanus superbubble

21. KOMPANEETS MODEL FITTING of the ORION-ERIDANUS SUPERBUBBLE. II. THINKING OUTSIDE of BARNARD'S LOOP

22. Mid-J CO Shock Tracing Observations of Infrared Dark Clouds. III. SLED Fitting

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

24. Deuterium Fractionation in the Ophiuchus Molecular Cloud

25. The Origin of Ionized Filaments Within the Orion-Eridanus Superbubble

26. Mid-JCO shock tracing observations of infrared dark clouds

27. Modes of Star Formation in Finite Molecular Clouds

28. Erratum: Mid-J CO observations of Perseus B1-East 5: evidence for turbulent dissipation via low-velocity shocks

29. CORRELATING INFALL WITH DEUTERIUM FRACTIONATION IN DENSE CORES

30. A First Look at BISTRO Observations of the ρ Oph-A core.

31. Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544.

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

33. The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations.

34. The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament.

35. KOMPANEETS MODEL FITTING OF THE ORION–ERIDANUS SUPERBUBBLE. II. THINKING OUTSIDE OF BARNARD’S LOOP.

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35 results on '"Andy Pon"'

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