检索结果-南通市图书馆

Molecular Gas and Dust in the Massive Star Forming Region S 233 IR

Chinese Journal of Astronomy and Astrophysics 2004年第5期4卷 440-454页

作者： Rui-Qing Mao and Qin Zeng1 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 2 national astronomical observatories, Chinese Academy of Sciences, Beijing 100012 Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 national astronomical observatories CAS NAOC Beijing 100012 China

The massive star forming region S 233 IR is observed in the molecular lines CO J = 2–1, 3–2, NH3 (1,1), (2,2) and the 870 um dust continuum. Four submillimeter continuum sources, labelled SMM 1–4, are revealed in the 870 um dust emission. The main core, SMM1, is found to be associated with a deeply embedded near infrared cluster in the northeast; while the weaker source SMM2 coincides with a more evolved cluster in the southwest. The best fit spectral energy distribution of SMM1 gives an emissivity of β = 1.6, and temperatures of 32 K and 92 K for the cold- and hot-dust components. An SMM1 core mass of 246 M☉, and a total mass of 445 M☉ are estimated from the 870 um dust continuum emission. SMM1 is found to have a temperature gradient decreasing from inside out, indicative of the presence of interior heating sources. The total outflow gas mass as traced by the CO J = 3–2 emission is estimated to be 35 M☉. Low velocity outflows are also found in the NH3 (1,1) emission. The non-thermal dominant NH3 line width as well as the substantial core mass suggest that the SMM1 core is a ``turbulent, massive dense core', in the process of forming a group or a cluster of stars. The much higher star formation efficiency found in the southwest cluster supports the suggestion that this cluster is more evolved than the northeast one. Large near infrared photometric variations found in the source PCS-IR93, a previously found highly polarized nebulosity, indicate an underlying star showing the FU Orionis type of behavior.

关键词： ISM: jets and outflows ISM: molecules ISM: dust, extinction stars:formation ISM: individual

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The relationship of extended radio power and broad emission line luminosity in blazars

引用

Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 240-243页

作者： LIU HongTao & Bai JinMing national astronomical observatories/Yunnan Observatory,Chinese Academy of Sciences,Kunming 650011,China national astronomical observatories/Yunnan Observatory Chinese Academy of Sciences Kunming China

The relationship between broad line luminosity LBLR and extended radio power PE is investigated.In the log PE-log LBLR diagram,FSRQs populate the region of higher luminosity relative to BL Lacs,and FR II BL Lacs are between FSRQs and FR I BL Lacs.For these blazars,there is a significant correlation between LBLR and PE.The regression line scales as PE ∝ L0B.L87R ± 0.15.The slope of this scaling relation is consistent with that derived from the simple theoretical formulae.Thus,the unification of BL Lacs and FRSQs into a single population finds a statistical basis,and a disk-jet symbiosis in blazars is confirmed.FR II BL Lacs are probably at an intermediate stage in the sequence from FSRQs to BL Lacs with FR I BL Lacs at the end of this sequence.

关键词： accretion black hole physics BL Laceratae objects:general galaxies:nuclei quasars:general

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optical Extinctions of Inter-Arm Molecular Clouds in M31: A Pilot Study for the Upcoming CSST Observations

引用

Research in Astronomy and Astrophysics 2024年第6期24卷 325-335页

作者： Cailing Chen Zheng Zheng Chao-Wei Tsai Sihan Jiao Jing Tang Jingwen Wu Di Li Yun Zheng Linjing Feng Yujiao Yang Yuan Liang national astronomical observatories Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Zhejiang Lab

Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in M31. However, the effectiveness of this technique is limited to its sensitivity, making it challenging to study more distant galaxies. This study introduces an alternative approach, utilizing optical extinctions derived from space-based telescopes, with a focus on the forthcoming China Space Station Telescope（CSST）. We first demonstrate the capability of this method by constructing dust extinction maps for 17 inter-arm massive molecular clouds in M31 using the Panchromatic Hubble Andromeda Treasury data. Our analysis reveals that inter-arm massive molecular clouds with an optical extinction（AV） greater than 1.6 mag exhibit a notable AVexcess, facilitating their identification. The majority of these inter-arm massive molecular clouds show an AVaround 1 mag, aligning with measurements from our JCMT data. Further validation using a mock CSST RGB star catalog confirms the method's effectiveness. We show that the derived AVvalues using CSST z and y photometries align more closely with the input values. Molecular clouds with AV> 1.6 mag can also be identified using the CSST mock data. We thus claim that future CSST observation clouds provide an effective way for the detection of inter-arm massive molecular clouds with significant optical extinction in nearby galaxies.

关键词： Galaxy: structure infrared: stars ISM: clouds

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The emission positions of kHz QPOs and Kerr spacetime influence

引用

Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 114-116页

作者： ZHANG ChengMin1,WEI YingChun1,YIN HongXing1,ZHAO YongHeng1,LEI YaJuan2,SONG LiMing2,ZHANG Fan2 & YAN Yan3 1 national astronomical observatories,Chinese Academy of Sciences,Beijing 100012,China 2 Institute of High Energy Physics,Chinese Academy of Sciences,19B Yuquan Road,Beijing 100049,China 3 Urumqi Observatory,national astronomical observatories,CAS,Urumqi 830011,China national astronomical observatories Chinese Academy of Sciences Beijing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China Urumqi Observatory National Astronomical Observatories CAS Urumqi China

Based the Alfven wave oscillation model(AWOM) and relativistic precession model(RPM) for twin kHz QPOs,we estimate the emission positions of most detected kHz QPOs to be at r=18+/-3 km(R/15 km),except Cir X-1 at r-30+/-5 km(R/15 km).For the proposed Keplerian frequency as an upper limit to kHz QPO,the spin effects in Kerr Spacetime are discussed,which have about a 5%(2%) modification for that of the Schwarzchild case for the spin frequency of 1000(400) Hz.The application to the four typical QPO sources,Cir X-1,Sco X-1,SAX J1808.4-3658 and XTE 1807-294,is mentioned.

关键词： kHz QPO neutron star low-mass X-ray binaries

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Possible Origin of 6.7 GHz Linear Methanol Maser Sources

引用

Chinese Journal of Astronomy and Astrophysics 2001年第5期1卷 389-394页

作者： Ye Xu (Shanghai astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030) (Urumqi astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011) (national astronomical observatories, Chinese Academy of Sciences, Beijing 100012) E-mail Shanghai astronomical Observatory Chinese Academy of Sciences Shanghai 200030 Urumqi astronomical Observatory Chinese Academy of Sciences Urumqi 830011 national astronomical observatories Chinese Academy of Sciences Beijing 100012

We present a model which explains the observed multi-linear spatial structures with different velocity gradients of the 50-61A+ methanol line at 6.7 GHz. We consider this and other hypotheses and conclude that the met... 详细信息

关键词： masers - stars: circumstellar matter - stars: formation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The First Ground-based White Light Lunar Polarization Imaging: A New Kind of FeO Observation on the Near Side of the Moon

引用

Research in Astronomy and Astrophysics 2024年第6期 3-8页

作者： Wei-Nan Wang Jin-Song Ping Ming-Yuan Wang Wen-Zhao Zhang Han-Lin Ye Xing-Wei Han Song-Feng Kou Changchun Observatory National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences national astronomical observatories Chinese Academy of Sciences Astronomy Department Beijing Normal University International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Nanjing Institute of astronomical Optics and Technology Chinese Academy of Sciences

Lunar optical polarization is a fascinating phenomenon that occurs when sunlight reflects off the surface of the Moon and becomes polarized. This study employs a novel split-focus plane polarimetric camera to conduct the initial white light polarimetric observations on the near side of the Moon. We obtained the linear degree of polarization(DOP) parameters of white light by observation from the eastern and western hemispheres of the Moon. The findings indicate that the white light polarization is lower in the lunar highland than in the lunar maria overall. Combining the analysis of lunar soil samples, we noticed and determined that the DOP parameters of white light demonstrate high consistency with iron oxide on the Moon. This study may serve as a new diagnostic tool for the Moon.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Laser altimetry data of Chang'E-1 and the global lunar DEM model

引用

Science China Earth Sciences 2010年第11期53卷 1582-1593页

作者： LI ChunLai1, REN Xin1, LIU JianJun1, ZOU XiaoDuan1, MU LingLi1, WANG JianYu2, SHU Rong2, ZOU YongLiao1, ZHANG HongBo1, Lü Chang1, LIU JianZhong1, ZUO Wei1, SU Yan1, WEN WeiBin1, BIAN Wei1, WANG Min1, XU Chun1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG Liang1, ZHANG ZhouBin1, ZHENG Lei1, ZHU XinYing1, LI JunDuo1 & OUYANG ZiYuan1 1 national astronomical observatories, Chinese Academy of Sciences, Beijing 100012, China 2 Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China national astronomical observatories Chinese Academy of Sciences Beijing China Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai China

The Laser AltiMeter (LAM), as one of the main payloads of Chang'E-1 probe, is used to measure the topography of the lunar surface. It performed the first measurement at 02:22 on November 28th, 2007. Up to December 4th 2008, the total number of measurements was approximately 9.12 million, covering the whole surface of the Moon. Using the LAM data, we constructed a global lunar Digtal Elevation Model (DEM) with 3 km spatial resolution. The model shows pronounced morphological characteristics, legible and vivid details of the lunar surface. The plane positioning accuracy of the DEM is 445 m (1σ), and the vertical accuracy is 60 m (1σ). From this DEM model, we measured the full range of the altitude difference on the lunar sur-face, which is about 19.807 km. The highest point is 10.629 km high, on a peak between crater Korolev and crater Dirichlet-Jackson at (158.656°W, 5.441°N) and the lowest point is -9.178 km in height, inside crater Antoniadi (172.413°W, 70.368°S) in the South Pole-Aitken Basin. By comparison, the DEM model of Chang'E-1 is better than the USA ULCN2005 in accuracy and resolution and is probably identical to the DEM of Japan SELENE, but the DEM of Chang'E-1 reveals a new lowest point, clearly lower than that of SELENE.

关键词： Chang’E-1 laser altimetry lunar DEM topographic tops of the Moon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

引用

Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming Wei Yi-Ming Zhu Zhi-Ping Jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China national astronomical observatories/Nanjing Institute of astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 UTC.Follow-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA instruments.AT2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst time.Here we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 UTC.Using afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations well.Considering that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced well.The initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation efficiency.When compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB samples.Additionally,the luminosity of AT2021lfa falls within the range of observations for GRB samples;however,approximately 1 day after the burst,its lumino

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Hierarchical Method for Locating the Interferometric Fringes of Celestial Sources in the Visibility Data

引用

Research in Astronomy and Astrophysics 2024年第3期24卷 110-128页

作者： Rong Ma Ruiqing Yan Hanshuai Cui Xiaochun Cheng Jixia Li Fengquan Wu Zongyao Yin Hao Wang Wenyi Zeng Xianchuan Yu School of Artificial Intelligence Beijing Normal UniversityBeijing 100875China Department of Computer Science Swansea UniversitySwanseaSA18ENUK national astronomical observatories Chinese Academy of SciencesBeijing 100101China

In source detection in the Tianlai project,locating the interferometric fringe in visibility data accurately will influence downstream tasks drastically,such as physical parameter estimation and weak source exploration.Considering that traditional locating methods are time-consuming and supervised methods require a great quantity of expensive labeled data,in this paper,we first investigate characteristics of interferometric fringes in the simulation and real scenario separately,and integrate an almost parameter-free unsupervised clustering method and seeding filling or eraser algorithm to propose a hierarchical plug and play method to improve location accuracy.Then,we apply our method to locate single and multiple sources’interferometric fringes in simulation data.Next,we apply our method to real data taken from the Tianlai radio telescope array.Finally,we compare with unsupervised methods that are state of the art.These results show that our method has robustness in different scenarios and can improve location measurement accuracy effectively.

关键词： methods data analysis-techniques image processing-techniques interferometric

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Infrared Galaxies in the Nearby Universe

引用

Chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 643-652页

作者： Jian-Ling Wang 1 national astronomical observatories,Chinese Academy of Sciences,Beijing 100012,China 2 Graduate School of Chinese Academy of Sciences,Beijing 100049,China national astronomical observatories Chinese Academy of Sciences Beijing 100012 China Graduate School of Chinese Academy of Sciences Beijing 100049 China

We used the Sloan Digital Sky Survey （SDSS） Data Release 5 （DR5） to study the morphological properties of 1137 nearby infrared （IR） galaxies, most of which are brighter than 15.9 mag in r-band. This sample was drawn from a cross-correlation of the Infra-Red astronomical Satellite （IRAS） point source catalog redshift survey with DR5 at z ≤ 0.08. Based on this IR galaxy sample, we constructed five volume-limited sub-samples with IR luminosity ranging from 10^9.5 L⊙ to 10^12L⊙. By deriving the IR luminosity functions （LF） for different morphological types, we found that normal spiral galaxies are the dominant population below LIR ~ 8 ~ 10^10 L⊙; while the fraction of barred spiral galaxies increases with increasing IR luminosity and becomes dominant in spiral galaxies beyond LIR ≈ 5 × 10^10L⊙. As the IR luminosity decreases, the IR galaxies become more compact and have lower stellar masses. The analysis also shows that normal spiral galaxies give the dominant contribution to the total comoving IR energy density in the nearby universe, while, in contrast, the contribution from peculiar galaxies is only 39%.

关键词： galaxies evolution galaxies interactions galaxies starburst infrared galaxies galaxies luminosity function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：