Pub Date : 2024-01-25DOI: 10.3847/1538-4357/ad062f
Y. Notsu, Adam F. Kowalski, Hiroyuki Maehara, K. Namekata, Kenji Hamaguchi, T. Enoto, Isaiah I. Tristan, S. Hawley, J. Davenport, Satoshi Honda, K. Ikuta, Shun Inoue, Keiichi Namizaki, D. Nogami, Kazunari Shibata
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate Aperture Research Telescope System 1.5 m telescopes during 31 nights. Among the 41 detected flares, seven flares showed clear blue wing asymmetries in the Hα line, with various correspondences in flare properties. The duration of the blue wing asymmetries range from 20 minutes to 2.5 hr, including a flare showing the shift from blue to red wing asymmetry. Blue wing asymmetries can be observed during both white-light and candidate non-white-light flares. All of the seven flares showed blue wing asymmetries also in the Hβ line, but there are large varieties on which other chromospheric lines showed blue wing asymmetries. One among the 7 flares was also observed with soft X-ray spectroscopy, which enabled us to estimate the flare magnetic field and length of the flare loop. The line-of-sight velocities of the blueshifted components range from –73 to –122 km s−1. Assuming that the blueshifts were caused by prominence eruptions, the mass of upward-moving plasma was estimated to be 1015–1019 g, which are roughly on the relation between flare energy and erupting mass expected from solar coronal mass ejections (CMEs). Although further investigations are necessary for understanding the observed various properties, these possible prominence eruptions on M-dwarfs could evolve into CMEs, assuming the similar acceleration mechanism with solar eruptions.
{"title":"Apache Point Observatory (APO)/SMARTS Flare Star Campaign Observations. I. Blue Wing Asymmetries in Chromospheric Lines during Mid-M-Dwarf Flares from Simultaneous Spectroscopic and Photometric Observation Data","authors":"Y. Notsu, Adam F. Kowalski, Hiroyuki Maehara, K. Namekata, Kenji Hamaguchi, T. Enoto, Isaiah I. Tristan, S. Hawley, J. Davenport, Satoshi Honda, K. Ikuta, Shun Inoue, Keiichi Namizaki, D. Nogami, Kazunari Shibata","doi":"10.3847/1538-4357/ad062f","DOIUrl":"https://doi.org/10.3847/1538-4357/ad062f","url":null,"abstract":"\u0000 We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate Aperture Research Telescope System 1.5 m telescopes during 31 nights. Among the 41 detected flares, seven flares showed clear blue wing asymmetries in the Hα line, with various correspondences in flare properties. The duration of the blue wing asymmetries range from 20 minutes to 2.5 hr, including a flare showing the shift from blue to red wing asymmetry. Blue wing asymmetries can be observed during both white-light and candidate non-white-light flares. All of the seven flares showed blue wing asymmetries also in the Hβ line, but there are large varieties on which other chromospheric lines showed blue wing asymmetries. One among the 7 flares was also observed with soft X-ray spectroscopy, which enabled us to estimate the flare magnetic field and length of the flare loop. The line-of-sight velocities of the blueshifted components range from –73 to –122 km s−1. Assuming that the blueshifts were caused by prominence eruptions, the mass of upward-moving plasma was estimated to be 1015–1019 g, which are roughly on the relation between flare energy and erupting mass expected from solar coronal mass ejections (CMEs). Although further investigations are necessary for understanding the observed various properties, these possible prominence eruptions on M-dwarfs could evolve into CMEs, assuming the similar acceleration mechanism with solar eruptions.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"28 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139596983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-25DOI: 10.3847/1538-4357/ad0466
R. Sultana, A. Le Gall, T. Tokano, L. Bonnefoy, M. Coutelier, R. Lorenz
From 2004 to 2017, the Cassini RADAR recorded the 2.2 cm thermal emission from Titan’s surface in its passive (radiometry) mode of operation. We use this data set to investigate the seasonal evolution of the effective temperature sensed by the microwave radiometer in two regions in the northern pole of the satellite: the sea Ligeia Mare, and its nearby solid terrains. We find that despite the arrival of summer at the end of the mission, the effective temperature of Ligeia Mare decreased by almost 1 K, while that of the solid region slowly increased until 2017 by 1.4 ± 0.3 K. These observations, as well as the lag in summer warming observed by Cassini’s Composite Infrared Spectrometer, can be explained by evaporative cooling in both the solid and liquid surfaces after the vernal equinox. It therefore supports the idea that the northern polar terrains are wet. Using an ocean circulation model, we show that the cooling of the sea surface should initiate convection in the sea’s interior, ultimately cooling the whole liquid column sensed by the Cassini radiometer and thus decreasing the temperature at depths even long after the evaporation period has ceased. Overall, this work highlights the key role of methane hydrology in controlling the surface and submarine temperatures in the boreal polar regions of Titan.
{"title":"Taking Titan’s Boreal Pole Temperature: Evidence for Evaporative Cooling in Ligeia Mare","authors":"R. Sultana, A. Le Gall, T. Tokano, L. Bonnefoy, M. Coutelier, R. Lorenz","doi":"10.3847/1538-4357/ad0466","DOIUrl":"https://doi.org/10.3847/1538-4357/ad0466","url":null,"abstract":"\u0000 From 2004 to 2017, the Cassini RADAR recorded the 2.2 cm thermal emission from Titan’s surface in its passive (radiometry) mode of operation. We use this data set to investigate the seasonal evolution of the effective temperature sensed by the microwave radiometer in two regions in the northern pole of the satellite: the sea Ligeia Mare, and its nearby solid terrains. We find that despite the arrival of summer at the end of the mission, the effective temperature of Ligeia Mare decreased by almost 1 K, while that of the solid region slowly increased until 2017 by 1.4 ± 0.3 K. These observations, as well as the lag in summer warming observed by Cassini’s Composite Infrared Spectrometer, can be explained by evaporative cooling in both the solid and liquid surfaces after the vernal equinox. It therefore supports the idea that the northern polar terrains are wet. Using an ocean circulation model, we show that the cooling of the sea surface should initiate convection in the sea’s interior, ultimately cooling the whole liquid column sensed by the Cassini radiometer and thus decreasing the temperature at depths even long after the evaporation period has ceased. Overall, this work highlights the key role of methane hydrology in controlling the surface and submarine temperatures in the boreal polar regions of Titan.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"27 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139597177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad2266
Xing-wei Chen, Xiaobin Zhang, Yan Li, Jie Su
Based on 2 minutes cadence TESS data, we investigate pulsations of TIC 65138566 and TIC 139729335 and discover them to be two new high-amplitude δ Scuti stars with equally spaced g modes. We recognize the radial fundamental mode f 1 = 18.3334 c d−1 and the first overtone f 3 = 23.6429 c d−1 for TIC 65138566, and identify the highest peak f 1 = 19.0955 c d−1 as the radial fundamental mode for TIC 139729335. For g modes, both stars display a regular period spacing of 2413 s. Through detailed seismological analysis, we deduce that these period-spacing patterns correspond to modes with ℓ = 1. Moreover, our analysis reveals that with increases in masses and metallicities, the star should display a higher degree of evolution to match a specific period spacing Π0. Conversely, the star should have a lower extent of evolution to match the radial fundamental mode. These two contradictory behaviors allow us to precisely obtain stellar physical parameters. TIC 65138566 and TIC 139729335 are determined to be two main-sequence stars that have almost the same range of masses and metallicities, with M = 1.36 ± 0.06 M ⊙ and Z = 0.005 ± 0.002. The hydrogen abundance in the core of TIC 65138566 is estimated to be about 0.28, while TIC 139729335 has a slightly higher value of around 0.31. Finally, we suggest that the high-amplitude δ Scuti–γ Doradus star TIC 308396022 is a main-sequence star with M = 1.54 ± 0.08 M ⊙, Z = 0.007 ± 0.001, and X c = 0.18 ± 0.02.
根据 2 分钟节奏的 TESS 数据，我们研究了 TIC 65138566 和 TIC 139729335 的脉动，发现它们是两颗具有等距 g 模式的新的高振幅 δ Scuti 星。我们识别出 TIC 65138566 的径向基模 f 1 = 18.3334 c d-1 和第一泛音 f 3 = 23.6429 c d-1，并确定最高峰 f 1 = 19.0955 c d-1 为 TIC 139729335 的径向基模。通过详细的地震学分析，我们推断这些周期间隔模式对应于 ℓ = 1 的模式。此外，我们的分析表明，随着质量和金属性的增加，恒星应该表现出更高的演化程度，以匹配特定的周期间隔Π0。相反，恒星的演化程度应该较低，以匹配径向基模。通过这两种相互矛盾的行为，我们可以精确地获得恒星的物理参数。经测定，TIC 65138566 和 TIC 139729335 是两颗质量和金属性范围几乎相同的主序星，M = 1.36 ± 0.06 M ⊙，Z = 0.005 ± 0.002。据估计，TIC 65138566 内核的氢丰度约为 0.28，而 TIC 139729335 的氢丰度略高，约为 0.31。最后，我们认为高振幅δ Scuti-γ Doradus恒星TIC 308396022是一颗主序星，其M = 1.54 ± 0.08 M ⊙，Z = 0.007 ± 0.001，X c = 0.18 ± 0.02。
{"title":"Two High-amplitude δ Scuti–γ Doradus Hybrids Constrained by the Radial Fundamental p and Equally Spaced g Modes","authors":"Xing-wei Chen, Xiaobin Zhang, Yan Li, Jie Su","doi":"10.3847/1538-4357/ad2266","DOIUrl":"https://doi.org/10.3847/1538-4357/ad2266","url":null,"abstract":"\u0000 Based on 2 minutes cadence TESS data, we investigate pulsations of TIC 65138566 and TIC 139729335 and discover them to be two new high-amplitude δ Scuti stars with equally spaced g modes. We recognize the radial fundamental mode f\u0000 1 = 18.3334 c d−1 and the first overtone f\u0000 3 = 23.6429 c d−1 for TIC 65138566, and identify the highest peak f\u0000 1 = 19.0955 c d−1 as the radial fundamental mode for TIC 139729335. For g modes, both stars display a regular period spacing of 2413 s. Through detailed seismological analysis, we deduce that these period-spacing patterns correspond to modes with ℓ = 1. Moreover, our analysis reveals that with increases in masses and metallicities, the star should display a higher degree of evolution to match a specific period spacing Π0. Conversely, the star should have a lower extent of evolution to match the radial fundamental mode. These two contradictory behaviors allow us to precisely obtain stellar physical parameters. TIC 65138566 and TIC 139729335 are determined to be two main-sequence stars that have almost the same range of masses and metallicities, with M = 1.36 ± 0.06 M\u0000 ⊙ and Z = 0.005 ± 0.002. The hydrogen abundance in the core of TIC 65138566 is estimated to be about 0.28, while TIC 139729335 has a slightly higher value of around 0.31. Finally, we suggest that the high-amplitude δ Scuti–γ Doradus star TIC 308396022 is a main-sequence star with M = 1.54 ± 0.08 M\u0000 ⊙, Z = 0.007 ± 0.001, and X\u0000 c = 0.18 ± 0.02.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"75 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140496858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad1409
H. Zou, Jipeng Sui, A. Saintonge, D. Scholte, J. Moustakas, M. Siudek, A. Dey, S. Juneau, Weijian Guo, R. Canning, J. Aguilar, S. Ahlen, D. Brooks, T. Claybaugh, K. Dawson, A. de la Macorra, P. Doel, J. Forero-Romero, S. Gontcho A Gontcho, K. Honscheid, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. Nie, C. Poppett, M. Rezaie, G. Rossi, E. Sanchez, M. Schubnell, H. Seo, G. Tarlé, Zhi-min Zhou, Siwei Zou
Extremely metal-poor galaxies (XMPGs) at relatively low redshift are excellent laboratories for studying galaxy formation and evolution in the early universe. Much effort has been spent on identifying them from large-scale spectroscopic surveys or spectroscopic follow-up observations. Previous work has identified a few hundred XMPGs. In this work, we obtain a large sample of 223 XMPGs at z < 1 from the early data of the Dark Energy Spectroscopic Instrument (DESI). The oxygen abundance is determined using the direct T e method based on the detection of the [O iii]λ4363 line. The sample includes 95 confirmed XMPGs based on the oxygen abundance uncertainty; the remaining 128 galaxies are regarded as XMPG candidates. These XMPGs are only 0.01% of the total DESI observed galaxies. Their coordinates and other properties are provided in the paper. The most XMPGs have an oxygen abundance of ∼1/34 Z ⊙, a stellar mass of about 1.5 × 107 M ⊙, and a star formation rate of 0.22 M ⊙ yr−1. The two most XMPGs present distinct morphologies suggesting different formation mechanisms. The local environmental investigation shows that XMPGs preferentially reside in relatively low-density regions. Many of them fall below the stellar mass–metallicity relations (MZRs) of normal star-forming galaxies. From a comparison of the MZR with theoretical simulations, it appears that XMPGs are good analogs to high-redshift star-forming galaxies. The nature of these XMPG populations will be further investigated in detail with larger and more complete samples from the ongoing DESI survey.
红移相对较低的极贫金属星系（XMPGs）是研究早期宇宙中星系形成和演化的绝佳实验室。人们花费了大量精力从大规模光谱巡天或光谱跟踪观测中识别它们。以前的工作已经发现了几百个XMPG。在这项工作中，我们从暗能量光谱仪（DESI）的早期数据中获得了 z < 1 的 223 个 XMPGs 大样本。氧丰度是根据[O iii]λ4363线的探测结果，用直接T e法测定的。根据氧丰度的不确定性，该样本包括 95 个已确认的 XMPG；其余 128 个星系被视为 XMPG 候选星系。这些 XMPG 只占 DESI 观测星系总数的 0.01%。本文提供了它们的坐标和其他属性。最多的 XMPGs 的氧丰度为 ∼1/34 Z ⊙，恒星质量约为 1.5 × 107 M ⊙，恒星形成率为 0.22 M ⊙ yr-1。两个最XMPGs呈现出不同的形态，表明其形成机制各不相同。局地环境调查显示，XMPGs偏好居住在密度相对较低的区域。它们中的许多都低于正常恒星形成星系的恒星质量-金属性关系（MZR）。从 MZR 与理论模拟的比较中可以看出，XMPG 是高红移恒星形成星系的良好模拟对象。我们将利用正在进行的DESI巡天中更大和更完整的样本，进一步详细研究这些XMPG群的性质。
{"title":"A Large Sample of Extremely Metal-poor Galaxies at z < 1 Identified from the DESI Early Data","authors":"H. Zou, Jipeng Sui, A. Saintonge, D. Scholte, J. Moustakas, M. Siudek, A. Dey, S. Juneau, Weijian Guo, R. Canning, J. Aguilar, S. Ahlen, D. Brooks, T. Claybaugh, K. Dawson, A. de la Macorra, P. Doel, J. Forero-Romero, S. Gontcho A Gontcho, K. Honscheid, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. Nie, C. Poppett, M. Rezaie, G. Rossi, E. Sanchez, M. Schubnell, H. Seo, G. Tarlé, Zhi-min Zhou, Siwei Zou","doi":"10.3847/1538-4357/ad1409","DOIUrl":"https://doi.org/10.3847/1538-4357/ad1409","url":null,"abstract":"\u0000 Extremely metal-poor galaxies (XMPGs) at relatively low redshift are excellent laboratories for studying galaxy formation and evolution in the early universe. Much effort has been spent on identifying them from large-scale spectroscopic surveys or spectroscopic follow-up observations. Previous work has identified a few hundred XMPGs. In this work, we obtain a large sample of 223 XMPGs at z < 1 from the early data of the Dark Energy Spectroscopic Instrument (DESI). The oxygen abundance is determined using the direct T\u0000 e method based on the detection of the [O iii]λ4363 line. The sample includes 95 confirmed XMPGs based on the oxygen abundance uncertainty; the remaining 128 galaxies are regarded as XMPG candidates. These XMPGs are only 0.01% of the total DESI observed galaxies. Their coordinates and other properties are provided in the paper. The most XMPGs have an oxygen abundance of ∼1/34 Z\u0000 ⊙, a stellar mass of about 1.5 × 107\u0000 M\u0000 ⊙, and a star formation rate of 0.22 M\u0000 ⊙ yr−1. The two most XMPGs present distinct morphologies suggesting different formation mechanisms. The local environmental investigation shows that XMPGs preferentially reside in relatively low-density regions. Many of them fall below the stellar mass–metallicity relations (MZRs) of normal star-forming galaxies. From a comparison of the MZR with theoretical simulations, it appears that XMPGs are good analogs to high-redshift star-forming galaxies. The nature of these XMPG populations will be further investigated in detail with larger and more complete samples from the ongoing DESI survey.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"65 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139601482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad07db
Lin Lu, Bin Sun, Zhen-Xing Fang, Meng Wan, Yunlu Gong
By means of astronomical observation data from the 60 cm Telescope at Yunnan Observatory, optical data in the g, r, and i bands were collected for BL Lac S5 0716+714, spanning from 2017 November 10 to 2018 May 15. The original data set contains 21,396 quasi-simultaneous multiband points, with 7132 data points for each band. The Lomb–Scargle periodogram method and the weighted wavelet Z-transform method were used to search for a quasi-periodic oscillation (QPO) signal in the data. For the first time, we report a QPO signal at 44 ± 6 days with a final significance of 3.98σ. Further analysis of the spectrum index reveals that the 44 day QPO signal is most likely explained by a helical motion of a blob with velocity β in the jet, where the viewing angle of the emission region in the jet undergoes periodic variations. In addition, we employed the hypothesis testing method (the null hypothesis) to analyze the flux distribution and determined that a double log-normal distribution provides a better fit; thus, there may be two radiative mini-regions within a jet in this source, so this 44 day QPO signal may be superimposed on a longer-term outburst.
{"title":"Research on a 44 Day Quasi-periodic Oscillation of Optical Bands for BL Lac S5 0716+714","authors":"Lin Lu, Bin Sun, Zhen-Xing Fang, Meng Wan, Yunlu Gong","doi":"10.3847/1538-4357/ad07db","DOIUrl":"https://doi.org/10.3847/1538-4357/ad07db","url":null,"abstract":"\u0000 By means of astronomical observation data from the 60 cm Telescope at Yunnan Observatory, optical data in the g, r, and i bands were collected for BL Lac S5 0716+714, spanning from 2017 November 10 to 2018 May 15. The original data set contains 21,396 quasi-simultaneous multiband points, with 7132 data points for each band. The Lomb–Scargle periodogram method and the weighted wavelet Z-transform method were used to search for a quasi-periodic oscillation (QPO) signal in the data. For the first time, we report a QPO signal at 44 ± 6 days with a final significance of 3.98σ. Further analysis of the spectrum index reveals that the 44 day QPO signal is most likely explained by a helical motion of a blob with velocity \u0000 β\u0000 in the jet, where the viewing angle of the emission region in the jet undergoes periodic variations. In addition, we employed the hypothesis testing method (the null hypothesis) to analyze the flux distribution and determined that a double log-normal distribution provides a better fit; thus, there may be two radiative mini-regions within a jet in this source, so this 44 day QPO signal may be superimposed on a longer-term outburst.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"69 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139601892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad2268
Satoko Takahashi, M. Machida, Mitsuki Omura, Doug Johnstone, K. Saigo, N. Harada, K. Tomisaka, Paul T. P. Ho, Luis A. Zapata, S. Mairs, G. Herczeg, Kotomi Taniguchi, Yuhua Liu, Asako Sato
We present ∼0.″2 (∼80 au) resolution observations of the CO(2–1) and SiO(5–4) lines made with the Atacama large millimeter/submillimeter array toward an extremely young intermediate-mass protostellar source (t dyn < 1000 yr), MMS 1 located in the Orion Molecular Cloud-3 region. We have successfully imaged a very compact CO molecular outflow associated with MMS 1, having deprojected lobe sizes of ∼1800 au (redshifted lobe) and ∼2800 au (blueshifted lobe). We have also detected an extremely compact (≲1000 au) and collimated SiO protostellar jet within the CO outflow. The maximum deprojected jet speed is measured to be as high as 93 km s−1. The SiO jet wiggles and displays a chain of knots. Our detection of the molecular outflow and jet is the first direct evidence that MMS 1 already hosts a protostar. The position–velocity diagram obtained from the SiO emission shows two distinct structures: (i) bow shocks associated with the tips of the outflow, and (ii) a collimated jet, showing the jet velocities linearly increasing with the distance from the driving source. Comparisons between the observations and numerical simulations quantitatively share similarities such as multiple-mass ejection events within the jet and Hubble-like flow associated with each mass ejection event. Finally, while there is a weak flux decline seen in the 850 μm light curve obtained with the James Clerk Maxwell Telescope/SCUBA 2 toward MMS 1, no dramatic flux change events are detected. This suggests that there has not been a clear burst event within the last 8 yr.
{"title":"An Extremely Young Protostellar Core, MMS 1/OMC-3: Episodic Mass Ejection History Traced by the Micro SiO Jet","authors":"Satoko Takahashi, M. Machida, Mitsuki Omura, Doug Johnstone, K. Saigo, N. Harada, K. Tomisaka, Paul T. P. Ho, Luis A. Zapata, S. Mairs, G. Herczeg, Kotomi Taniguchi, Yuhua Liu, Asako Sato","doi":"10.3847/1538-4357/ad2268","DOIUrl":"https://doi.org/10.3847/1538-4357/ad2268","url":null,"abstract":"\u0000 We present ∼0.″2 (∼80 au) resolution observations of the CO(2–1) and SiO(5–4) lines made with the Atacama large millimeter/submillimeter array toward an extremely young intermediate-mass protostellar source (t\u0000 dyn < 1000 yr), MMS 1 located in the Orion Molecular Cloud-3 region. We have successfully imaged a very compact CO molecular outflow associated with MMS 1, having deprojected lobe sizes of ∼1800 au (redshifted lobe) and ∼2800 au (blueshifted lobe). We have also detected an extremely compact (≲1000 au) and collimated SiO protostellar jet within the CO outflow. The maximum deprojected jet speed is measured to be as high as 93 km s−1. The SiO jet wiggles and displays a chain of knots. Our detection of the molecular outflow and jet is the first direct evidence that MMS 1 already hosts a protostar. The position–velocity diagram obtained from the SiO emission shows two distinct structures: (i) bow shocks associated with the tips of the outflow, and (ii) a collimated jet, showing the jet velocities linearly increasing with the distance from the driving source. Comparisons between the observations and numerical simulations quantitatively share similarities such as multiple-mass ejection events within the jet and Hubble-like flow associated with each mass ejection event. Finally, while there is a weak flux decline seen in the 850 μm light curve obtained with the James Clerk Maxwell Telescope/SCUBA 2 toward MMS 1, no dramatic flux change events are detected. This suggests that there has not been a clear burst event within the last 8 yr.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"44 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140497829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad0fe8
Ziteng Wang, David L. Kaplan, R. Sengar, E. Lenc, A. Zic, A. Anumarlapudi, B. M. Gaensler, N. Hurley-Walker, Tara Murphy, Yuanming Wang
We report the discovery of a young, highly scattered pulsar in a search for highly circularly polarized radio sources as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients survey. In follow-up observations with the Parkes radio telescope, Murriyang, we identified PSR J1032−5804 and measured a period of 78.7 ms, a dispersion measure of 819 ± 4 pc cm−3, a rotation measure of −2000 ± 1 rad m−2, and a characteristic age of 34.6 kyr. We found a pulse scattering timescale at 3 GHz of ∼22 ms, implying a timescale at 1 GHz of ∼3845 ms, which is the third most scattered pulsar known and explains its nondetection in previous pulsar surveys. We discuss the identification of a possible pulsar wind nebula and supernova remnant in the pulsar’s local environment by analyzing the pulsar spectral energy distribution and the surrounding extended emission from multiwavelength images. Our result highlights the possibility of identifying extremely scattered pulsars from radio continuum images. Ongoing and future large-scale radio continuum surveys will offer us an unprecedented opportunity to find more extreme pulsars (e.g., highly scattered, highly intermittent, and highly accelerated), which will enhance our understanding of the characteristics of pulsars and the interstellar medium.
我们报告说，在澳大利亚平方公里阵列探路者变星和慢瞬变巡天观测中，我们在对高圆极化射电源的搜索中发现了一颗年轻的高散射脉冲星。在利用墨里阳帕克斯射电望远镜进行的后续观测中，我们确定了 PSR J1032-5804，并测量出其周期为 78.7 毫秒，色散测量值为 819 ± 4 pc cm-3，自转测量值为 -2000 ± 1 rad m-2，特征年龄为 34.6 千年。我们发现在 3 GHz 的脉冲散射时间尺度为 ∼22 ms，这意味着在 1 GHz 的时间尺度为 ∼3845 ms，这是目前已知的第三大散射脉冲星，这也解释了为什么在以前的脉冲星巡天中没有发现它。我们讨论了通过分析脉冲星光谱能量分布和多波长图像中的周围扩展发射，识别脉冲星局部环境中可能存在的脉冲星风星云和超新星残余物。我们的结果凸显了从射电连续相图像中识别极度散乱脉冲星的可能性。正在进行的和未来的大规模射电连续面巡天将为我们提供一个前所未有的机会来发现更多的极端脉冲星（如高度散射、高度间歇和高度加速），这将加深我们对脉冲星和星际介质特征的理解。
{"title":"Discovery of a Young, Highly Scattered Pulsar PSR J1032-5804 with the Australian Square Kilometre Array Pathfinder","authors":"Ziteng Wang, David L. Kaplan, R. Sengar, E. Lenc, A. Zic, A. Anumarlapudi, B. M. Gaensler, N. Hurley-Walker, Tara Murphy, Yuanming Wang","doi":"10.3847/1538-4357/ad0fe8","DOIUrl":"https://doi.org/10.3847/1538-4357/ad0fe8","url":null,"abstract":"\u0000 We report the discovery of a young, highly scattered pulsar in a search for highly circularly polarized radio sources as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients survey. In follow-up observations with the Parkes radio telescope, Murriyang, we identified PSR J1032−5804 and measured a period of 78.7 ms, a dispersion measure of 819 ± 4 pc cm−3, a rotation measure of −2000 ± 1 rad m−2, and a characteristic age of 34.6 kyr. We found a pulse scattering timescale at 3 GHz of ∼22 ms, implying a timescale at 1 GHz of ∼3845 ms, which is the third most scattered pulsar known and explains its nondetection in previous pulsar surveys. We discuss the identification of a possible pulsar wind nebula and supernova remnant in the pulsar’s local environment by analyzing the pulsar spectral energy distribution and the surrounding extended emission from multiwavelength images. Our result highlights the possibility of identifying extremely scattered pulsars from radio continuum images. Ongoing and future large-scale radio continuum surveys will offer us an unprecedented opportunity to find more extreme pulsars (e.g., highly scattered, highly intermittent, and highly accelerated), which will enhance our understanding of the characteristics of pulsars and the interstellar medium.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"68 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139600566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.3847/1538-4357/ad0daa
Siddhartha Biswas, Soumen Mondal, Ariful Hoque, A. Panja, T. Baug, R. Das
We present a detailed study of the Sh2-87 H ii region using a multiwavelength data set in optical to radio bands. A Herschel column density map revealed that the host cloud is filamentary in nature, and together they formed a central dense hub. The extinction map generated using near-infrared photometric data also signifies the nonuniform distribution of the cloud and reveals its filamentary nature. We estimated a sizable variable extinction over the region up to A V = 34.4 mag, with an average value of A V = 3.4 mag. Using the various infrared color–color criteria, we identified 13 Class I and 202 Class II young stellar objects (YSOs) and 22 Hα-emitting sources toward this region. Further analysis showed that the cluster is mainly composed of low-mass YSOs with a typical age of ∼3 Myr having masses in the range of 0.1–6.0 M ⊙. The identified evolved YSOs (i.e., Class II YSOs) are primarily distributed along the filaments and in the outer parts of the cloud, while the recent star formation, inferred by the presence of Class I YSOs, ionized gas, and star-forming clumps, is observed in the hub region. The overall star formation scenario in the Sh2-87 region resembles the global hierarchical collapse model of star formation, where younger massive star formation activity is expected at the central hub along with the distribution of evolved low-mass YSOs in the filaments and the outer parts of the cloud.
我们利用从光学波段到射电波段的多波长数据集对 Sh2-87 H ii 区域进行了详细研究。赫歇尔柱密度图显示，宿主云具有丝状性质，它们共同形成了一个中心致密枢纽。利用近红外光度数据生成的消光图也显示了云的不均匀分布，并揭示了其丝状性质。我们估计该区域的消光有相当大的变化，最高可达 A V = 34.4 等，平均值为 A V = 3.4 等。利用不同的红外色度标准，我们确定了该区域的 13 个 I 类和 202 个 II 类年轻恒星天体（YSO）以及 22 个 Hα 辐射源。进一步的分析表明，该星团主要由低质量的YSO组成，其典型年龄为∼3 Myr，质量范围为0.1-6.0 M ⊙。已发现的演化YSOs（即II类YSOs）主要分布在云丝沿线和云的外围，而根据I类YSOs、电离气体和恒星形成团块的存在推断出的近期恒星形成则是在中心区域观测到的。Sh2-87 区域的总体恒星形成情况类似于恒星形成的全局分层坍缩模型，在该模型中，较年轻的大质量恒星形成活动预计会出现在中心枢纽，而演化的低质量 YSOs 则分布在丝状云和云的外部。
{"title":"Star Formation in the H ii Region Sh2-87: Evidence of Global Hierarchical Collapse","authors":"Siddhartha Biswas, Soumen Mondal, Ariful Hoque, A. Panja, T. Baug, R. Das","doi":"10.3847/1538-4357/ad0daa","DOIUrl":"https://doi.org/10.3847/1538-4357/ad0daa","url":null,"abstract":"\u0000 We present a detailed study of the Sh2-87 H ii region using a multiwavelength data set in optical to radio bands. A Herschel column density map revealed that the host cloud is filamentary in nature, and together they formed a central dense hub. The extinction map generated using near-infrared photometric data also signifies the nonuniform distribution of the cloud and reveals its filamentary nature. We estimated a sizable variable extinction over the region up to A\u0000 \u0000 V\u0000 = 34.4 mag, with an average value of A\u0000 \u0000 V\u0000 = 3.4 mag. Using the various infrared color–color criteria, we identified 13 Class I and 202 Class II young stellar objects (YSOs) and 22 Hα-emitting sources toward this region. Further analysis showed that the cluster is mainly composed of low-mass YSOs with a typical age of ∼3 Myr having masses in the range of 0.1–6.0 M\u0000 ⊙. The identified evolved YSOs (i.e., Class II YSOs) are primarily distributed along the filaments and in the outer parts of the cloud, while the recent star formation, inferred by the presence of Class I YSOs, ionized gas, and star-forming clumps, is observed in the hub region. The overall star formation scenario in the Sh2-87 region resembles the global hierarchical collapse model of star formation, where younger massive star formation activity is expected at the central hub along with the distribution of evolved low-mass YSOs in the filaments and the outer parts of the cloud.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"36 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139599447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.3847/1538-4357/ad0da3
Y. Fukui, Maki Aruga, H. Sano, Takahiro Hayakawa, T. Inoue, Gavin Rowell, S. Einecke, K. Tachihara
Fukui et al. quantified the hadronic and leptonic gamma-rays in the young TeV gamma-ray shell-type supernova remnant (SNR) RX J1713.7-3946 (RX J1713), and demonstrated that gamma rays are a combination of hadronic and leptonic gamma-ray components with a ratio of ∼6: 4 in gamma-ray counts N g. This discovery, which adopted a new methodology of multi-linear gamma-ray decomposition, was the first quantification of the two gamma-ray components. In the present work, we applied the same methodology to another TeV gamma-ray shell-type SNR RX J0852.0-4622 (RXJ0852) in 3D space characterized by (the interstellar proton column density N p)-(the nonthermal X-ray count N x)-[N g], and quantified the hadronic and leptonic gamma-ray components as having a ratio of ∼5:5 in N g. The present work adopted the fitting of two/three flat planes in 3D space instead of a single flat plane, which allowed suppression of the fitting errors. This quantification indicates that hadronic and leptonic gamma-rays are of the same order of magnitude in these two core-collapse SNRs, verifying the significant hadronic gamma-ray components. We argue that the target interstellar protons, in particular their spatial distribution, are essential in any attempts to identify the type of particles responsible for gamma-ray emission. The present results confirm that cosmic-ray (CR) energy ≲100 TeV is compatible with a scheme in which SNRs are the dominant source of these Galactic CRs.
{"title":"The Gamma-Ray Origin of RX J0852.0-4622 Quantifying the Hadronic and Leptonic Components: Further Evidence for the Cosmic-Ray Acceleration in Young Shell-type SNRs","authors":"Y. Fukui, Maki Aruga, H. Sano, Takahiro Hayakawa, T. Inoue, Gavin Rowell, S. Einecke, K. Tachihara","doi":"10.3847/1538-4357/ad0da3","DOIUrl":"https://doi.org/10.3847/1538-4357/ad0da3","url":null,"abstract":"\u0000 Fukui et al. quantified the hadronic and leptonic gamma-rays in the young TeV gamma-ray shell-type supernova remnant (SNR) RX J1713.7-3946 (RX J1713), and demonstrated that gamma rays are a combination of hadronic and leptonic gamma-ray components with a ratio of ∼6: 4 in gamma-ray counts N\u0000 g. This discovery, which adopted a new methodology of multi-linear gamma-ray decomposition, was the first quantification of the two gamma-ray components. In the present work, we applied the same methodology to another TeV gamma-ray shell-type SNR RX J0852.0-4622 (RXJ0852) in 3D space characterized by (the interstellar proton column density N\u0000 p)-(the nonthermal X-ray count N\u0000 x)-[N\u0000 g], and quantified the hadronic and leptonic gamma-ray components as having a ratio of ∼5:5 in N\u0000 g. The present work adopted the fitting of two/three flat planes in 3D space instead of a single flat plane, which allowed suppression of the fitting errors. This quantification indicates that hadronic and leptonic gamma-rays are of the same order of magnitude in these two core-collapse SNRs, verifying the significant hadronic gamma-ray components. We argue that the target interstellar protons, in particular their spatial distribution, are essential in any attempts to identify the type of particles responsible for gamma-ray emission. The present results confirm that cosmic-ray (CR) energy ≲100 TeV is compatible with a scheme in which SNRs are the dominant source of these Galactic CRs.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"47 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.3847/1538-4357/ad165b
Jia-Wei Wang, Patrick M. Koch, S. Clarke, G. Fuller, N. Peretto, Ya-wen Tang, Hsi-Wei Yen, S. Lai, N. Ohashi, D. Arzoumanian, Doug Johnstone, R. Furuya, S. Inutsuka, Chang Won Lee, D. Ward-Thompson, Valentin J. M. Le Gouellec, Hongli Liu, L. Fanciullo, J. Hwang, K. Pattle, F. Poidevin, M. Tahani, T. Onaka, M. Rawlings, E. Chung, Junhao Liu, A. Lyo, F. Priestley, T. Hoang, Motohide Tamura, D. Berry, P. Bastien, T. Ching, Simon Coud'e, W. Kwon, Mike Chen, C. Eswaraiah, A. Soam, Tetsuo Hasegawa, K. Qiu, T. Bourke, D. Byun, Zhiwei Chen, H. Chen, W. Chen, Jung‐Hwa Cho, Minho Choi, Yunhee Choi, Youngwoo Choi, A. Chrysostomou, S. Dai, J. di Francesco, Pham Ngoc Diep, Y. Doi, Y. Duan, H. Duan, D. Eden, J. Fiege, L. Fissel, E. Franzmann, P. Friberg, R. Friesen, Tim Gledhill, S. Graves, Jane Greaves, M. Griffin, Q. Gu, I. Han, S. Hayashi, M. Houde, Tsuyoshi Inoue, K. Iwasaki, Il-Gyo Jeong, V. Könyves, Ji-hyun Kang, Miju Kang, J. Karoly, A. Kataoka, K. Kawabata, Zacariyya Khan, Mi-Ryang Kim, Kee-Tae Kim, K. Kim, Sh
We report 850 μm continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B-fields In STar forming Regions Observations large program on the James Clerk Maxwell Telescope. These data reveal a well-structured nonuniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30° from north to east. Field strength estimates and a virial analysis of the major clumps indicate that NGC 2264C is globally dominated by gravity, while in 2264D, magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and longitudinal collapsing, driven by the region's global gravity.
我们报告了对丝状高质恒星形成区 NGC 2264 的 850 μm 连续极化观测数据，这些数据是詹姆斯-克拉克-麦克斯韦望远镜的 "恒星形成区 B 场观测"（B-fields In STar forming Regions Observations）大型计划的一部分。这些数据揭示了 NGC 2264C 和 2264D 区域内结构良好的非均匀磁场，其主要方向为北向东 30° 左右。对主要星团的磁场强度估算和病毒分析表明，NGC 2264C 在全球范围内受重力支配，而在 2264D 中，磁能、重力能和动能大致平衡。我们提出了一种分析方案，利用局部解析的磁场结构、局部测量的引力矢量场和提取的丝状网络。由此，我们推断出统计趋势，表明该网络由两大组方向大致相互垂直的细丝组成。此外，重力还显示出一个主要的汇聚方向，与其中一个丝状方向大致垂直，这表明质量沿该方向聚集。除了这些统计趋势之外，我们还发现了两种类型的细丝。I 型灯丝垂直于磁场，从灯丝脊外侧开始，局部重力从平行于磁场过渡到垂直于磁场。II 型灯丝与磁场和当地引力平行。我们将这两种类型的细丝解释为源于细丝自身引力驱动的径向塌缩和区域整体引力驱动的纵向塌缩之间的竞争。
{"title":"Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-mass Star-forming Region NGC 2264: Global Properties and Local Magnetogravitational Configurations","authors":"Jia-Wei Wang, Patrick M. Koch, S. Clarke, G. Fuller, N. Peretto, Ya-wen Tang, Hsi-Wei Yen, S. Lai, N. Ohashi, D. Arzoumanian, Doug Johnstone, R. Furuya, S. Inutsuka, Chang Won Lee, D. Ward-Thompson, Valentin J. M. Le Gouellec, Hongli Liu, L. Fanciullo, J. Hwang, K. Pattle, F. Poidevin, M. Tahani, T. Onaka, M. Rawlings, E. Chung, Junhao Liu, A. Lyo, F. Priestley, T. Hoang, Motohide Tamura, D. Berry, P. Bastien, T. Ching, Simon Coud'e, W. Kwon, Mike Chen, C. Eswaraiah, A. Soam, Tetsuo Hasegawa, K. Qiu, T. Bourke, D. Byun, Zhiwei Chen, H. Chen, W. Chen, Jung‐Hwa Cho, Minho Choi, Yunhee Choi, Youngwoo Choi, A. Chrysostomou, S. Dai, J. di Francesco, Pham Ngoc Diep, Y. Doi, Y. Duan, H. Duan, D. Eden, J. Fiege, L. Fissel, E. Franzmann, P. Friberg, R. Friesen, Tim Gledhill, S. Graves, Jane Greaves, M. Griffin, Q. Gu, I. Han, S. Hayashi, M. Houde, Tsuyoshi Inoue, K. Iwasaki, Il-Gyo Jeong, V. Könyves, Ji-hyun Kang, Miju Kang, J. Karoly, A. Kataoka, K. Kawabata, Zacariyya Khan, Mi-Ryang Kim, Kee-Tae Kim, K. Kim, Sh","doi":"10.3847/1538-4357/ad165b","DOIUrl":"https://doi.org/10.3847/1538-4357/ad165b","url":null,"abstract":"\u0000 We report 850 μm continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B-fields In STar forming Regions Observations large program on the James Clerk Maxwell Telescope. These data reveal a well-structured nonuniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30° from north to east. Field strength estimates and a virial analysis of the major clumps indicate that NGC 2264C is globally dominated by gravity, while in 2264D, magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and longitudinal collapsing, driven by the region's global gravity.","PeriodicalId":504209,"journal":{"name":"The Astrophysical Journal","volume":"28 2-4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140498403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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