检索结果-南通市图书馆

Scintillation Arc from FRB 20220912A

Science China(Physics,Mechanics & astronomy) 2024年第1期67卷 134-142页

作者： Zi-Wei Wu Robert AMain Wei-Wei Zhu Bing Zhang Peng Jiang Jia-Rui Niu Jin-Lin Han Di Li Ke-Jia Lee Dong-Zi Li Yuan-Pei Yang Fa-Yin Wang Rui Luo Pei Wang Chen-Hui Niu Heng Xu Bo-Jun Wang Wei-Yang Wang Yong-Kun Zhang Yi Feng De-Jiang Zhou Yong-Hua Xu Can-Min Deng Yu-Hao Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Max-Planck-Institut für Radioastronomie Bonn 53121Germany Institute for Frontier in astronomy and astrophysics Beijing Normal UniversityBeijing 102206China Nevada center for astrophysics and Department of Physics and astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of astronomy University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN Computational astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of astronomy Peking UniversityBeijing 100871China Kavli Institute for astronomy and astrophysics Peking UniversityBeijing 100871China cahill center for astronomy and astrophysics California Institute of TechnologyPasadena 91125USA South-Western Institute For astronomy Research Yunnan UniversityKunming 650504China School of astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern astronomy and astrophysics(Nanjing University) Ministry of EducationNanjing 210023China CSIRO Space and astronomy Epping 1710Australia Department of astronomy School of Physics and Materials ScienceGuangzhou UniversityGuangzhou 510006China Research center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Yunnan Observatories Chinese Academy of SciencesKunming 650011China Guangxi Key Laboratory for Relativistic astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

We present the interstellar scintillation analysis of fast radio burst(FRB)20220912A during its extremely active episode in 2022using data from the Five-hundred-meter Aperture Spherical Radio Telescope(FAST).We detect a scintillation arc in the FRB’s secondary spectrum,which describes the power in terms of the scattered FRB signals’time delay and Doppler shift.The arc indicates that the scintillation is caused by a highly localized region.Our analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy origin.We present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or pulses.These methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy.

关键词： fast radio burst scintillation FRB 20220912A

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

Probing turbulence in galaxies with fast radio burst scintillation

引用

Science China(Physics,Mechanics & astronomy) 2024年第1期67卷 177-178页

作者： James M.Cordes Department of astronomy the Cornell Center for Astrophysics and Planetary ScienceCornell UniversityIthaca NY 14853USA

Interstellar scintillation(ISS)is a well-known phenomenon observed from pulsars in the Milky Way.It comprises intensity variations vs.time and frequency caused by constructive and destructive interference from multipath propagation,which is due to diffraction from fluctuations in electron density in the interstellar medium(ISM)on scales as small as~100 km.These density fluctuations appear to be part of a turbulence process combined with discrete structures in electron density from other astrophysical processes;together these fluctuations extend to scales of pc or larger.

关键词： scales galaxies turbulence

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 Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays

引用

Research in astronomy and astrophysics 2024年第6期24卷 247-254页

作者： Tao Wen Songzhan Chen Benzhong Dai School of Physics and astronomy Yunnan University Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Tianfu Cosmic Ray Research center

With great advance of ground-based extensive air shower arrays, such as LHAASO and HAWC, many very high energy(VHE) gamma-ray sources have been discovered and are being monitored regardless of the day and the night. Hence, the Sun and Moon would have some impacts on the observation of gamma-ray sources, which have not been taken into account in previous analysis. In this paper, the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is estimated. The tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some period. The absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are achieved. The main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray background. The influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission.

关键词： astroparticle physics methods: observational Sun: general Sun: UV radiation

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

An Asymmetric Galactic Stellar Disk Traced by OB-type Stars from LAMOST DR7

引用

Research in astronomy and astrophysics 2024年第6期24卷 40-53页

作者： Xiaopeng Liu Hao Tian Wenyuan Cui Linlin Li Jiaming Liu Zhenyan Huo Yawei Gao Department of Physics Hebei Normal University Guo Shoujing Institute for astronomy Hebei Normal University Key Laboratory of Space astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Institute for Frontiers in astronomy and astrophysics Beijing Normal University

Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood,we fit the vertical stellar density profile with the model including a single exponential distribution at different positions （R,Φ）.The distributions of the scale heights and scale length show that the young disk traced by the OB-type stars is not axisymmetric.The scale length decreases versus the azimuthal angle Φ,i.e.,from.■kpc withΦ=-3°to■kpc withΦ=9°.Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk plane.The scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around hs=130 pc.The distribution of the displaceeent of the disk plane Z0also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid stars.We also test different values for the position of the Sun,and the distance between the Sun and the Galactic center affects the scale heights and the displacement of the disk significantly,but that does not change our conclusion that the disk is not axisymmetric.

关键词： galaxies: spiral Galaxy: disk stars: early-type stars: massive

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

Long-term Integration Ability of the Submillimeter Wave astronomy Satellite (SWAS) Spectral Line Receivers

引用

Research in astronomy and astrophysics 2024年第6期24卷 317-324页

作者： Bing-Ru Wang Di Li Paul F.Goldsmith Jingwen Wu Chao-Wei Tsai Rudolf Schieder Gary J.Melnick National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences Research center for Astronomical Computing Zhejiang Laboratory Jet Propulsion Laboratory California Institute of Technology Institute for Frontiers in astronomy and astrophysics Beijing Normal University KOSMA I.Physik.Institut Universit?t zu K?ln center for astrophysics | Harvard & Smithsonian

The Submillimeter Wave astronomy Satellite（SWAS） was the first space telescope capable of high spectral resolution observations of terahertz spectral lines. We have investigated the integration ability of its two receivers and spectrometer during five and a half years of on-orbit operation. The CI, O2, H2O, and13CO spectra taken toward all observed Galactic sources were analyzed. The present results are based on spectra with a total integration time of up to 2.72 × 10～4hr（■10～8s）. The noise in the spectra is generally consistent with that expected from the radiometer equation, without any sign of approaching a noise floor. This noise performance reflects the extremely stable performance of the passively cooled front end as well as other relevant components in the SWAS instrument throughout its mission lifetime.

关键词： instrumentation: miscellaneous ISM: lines and bands space vehicles: instruments telescopes

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

Detection of astrophysical gravitational wave sources by TianQin and LISA

引用

Science China(Physics,Mechanics & astronomy) 2024年第5期67卷 123-163页

作者： Alejandro Torres-Orjuela Shun-Jia Huang Zheng-Cheng Liang Shuai Liu Hai-Tian Wang Chang-Qing Ye Yi-Ming Hu Jianwei Mei MOE Key Laboratory of Tian Qin Mission Tian Qin Research Center for Gravitational PhysicsSchool of Physics and AstronomyFrontiers Science Center for Tian QinGravitational Wave Research Center of CNSASun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China Department of Physics The University of Hong KongHong Kong 999077China Kavli Institute for astronomy and astrophysics Peking UniversityBeijing100871China

TianQin and LISA are space-based laser interferometer gravitational wave(GW)detectors planned to be launched in the mid-2030s.Both detectors will detect low-frequency GWs around 10^(-2)Hz;however,Tian Qin is more sensitive to frequencies above this common sweet-spot while LISA is more sensitive to frequencies below 10^(-2)Hz.Therefore,Tian Qin and LISA will be able to detect the same sources but with different accuracy depending on the source and its parameters.We consider some of the most important astrophysical sources—massive black hole binaries,stellar-mass black hole binaries,double white dwarfs,extreme mass ratio inspirals,light and heavy intermediate mass ratio inspirals,as well as the stochastic gravitational background of astrophysical origin—that Tian Qin and LISA will be able to detect.For each of these sources,we analyze how far they can be detected(detection distance)and how well their parameters can be measured(detection accuracy)using a Fisher Matrix analysis.We compare the results obtained by the three detection scenarios(Tian Qin alone,LISA alone,and joint detection by LISA and Tian Qin)highlighting the gains from joint detection as well as the contribution of Tian Qin and LISA to a combined study of astrophysical sources.In particular,we consider the different orientations,lifetimes,and duty cycles of the two detectors to explore how they can give a more complete picture when working together.

关键词： wave extreme stochastic

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 FAST all sky HI survey(FASHI):The first release of catalog

引用

Science China(Physics,Mechanics & astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming Zhu Peng Jiang Cheng Cheng Jing Wang Jie Wang Jin-Long Xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei Ai Yingjie Jing Chen Xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao FAST Collaboration Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China National Astronomical Observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America center for astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli Institute for astronomy and astrophysics Peking UniversityBeijing 100871China

The FAST All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(FAST),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI sources.Between August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by FAST.It has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 GHz.As of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■0.09.By cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric redshifts.Most of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar sources.Based on current survey results,the FASHI survey is an unprecedented blind extragalactic H I survey.It has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey(ALFALFA).When completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

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

Probing the Gamma-Ray Emission Region of Five TeV Flat Spectrum Radio Quasars

引用

Research in astronomy and astrophysics 2024年第6期24卷 158-171页

作者： Hu-Bing Xiao Hai-Tao Cao Rui Xue Jin-Ting Cai Ge-Ge Wang Marina Manganaro Shao-Hua Zhang Zhi-Hao Ouyang Li-Ping Fu Jun-Hui Fan Shanghai Key Lab for astrophysics Shanghai Normal University School of Information Engineering Department of Physics Zhejiang Normal University College of Mathematics and Physics Guangxi Minzu University Key Laboratory of Cosmology and astrophysics (Liaoning) College of Sciences Northeastern University Department of Physics University of Rijeka center for astrophysics Guangzhou University Key Laboratory for Astronomical Observation and Technology of Guangzhou astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province

The location of γ-ray emission of blazars remains a contested topic, inspiring the development of numerous investigative techniques to address this issue. In this work, we analyzed Fermi γ-ray light curves in the GeV and MeV bands, employing the discrete cross-correlation function method to discern time lags between the two bands.For 4C +21.35, Ton 599, B2 1420+32, and PKS 1510-089, we identified a time lag spanning several days, while for PKS 1441+25, the time lag was not statistically found. The results imply that the soft photons necessary for inverse Compton scattering predominantly originate from the dusty torus in the first four sources, whereas for PKS1441+25, they seem to be sourced mainly from the broad-line region. Further analysis of the opacity(τγγ) and the GeV spectra study supports the conclusion that the location of the dissipation region must be beyond the BLR to avoid significant absorption. Notably, for PKS 1441+25, the emission region is also posited to lie outside yet proximate to the BLR. The parameters of describing the emission region were obtained by fitting broadband spectral energy distribution with contemporaneous observation data. Our findings suggest that for the five TeV FSRQs, during Te V flaring events, the jet appears to maintain an equilibrium between the energy density of the magnetic field and that of the particles for all investigated sources, with the exceptions of 4C +21.35 and PKS1441+25. In terms of the overall jet power, particle energy is the dominant contributor, and the observed blazar radiation cannot be solely attributed to the magnetic field, except in the case of 4C +21.35. Consequently,magnetic reconnection is unlikely to be the primary mechanism behind particle acceleration in these systems.

关键词： galaxies: active galaxies: jets gamma-rays: galaxies

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

Spin Evolution of the Magnetar SGR J1935+2154

引用

Research in astronomy and astrophysics 2024年第1期24卷 201-211页

作者： Ming-Yu Ge Yuan-Pei Yang Fang-Jun Lu Shi-Qi Zhou Long Ji Shuang-Nan Zhang Bing Zhang Liang Zhang Pei Wang Kejia Lee Weiwei Zhu Jian Li Xian Hou Qiao-Chu Li Key Laboratory of Particle astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China South-Western Institute For astronomy Research Yunnan UniversityKunming 650504China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China Key Laboratory of Stellar and Interstellar Physics and School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China School of Physics and astronomy Sun Yat-Sen UniversityZhuhai 519082China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Nevada center for astrophysics University of NevadaLas VegasNV 89154USA Department of Physics and astronomy University of NevadaLas VegasNV 89154USA National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Department of astronomy Peking UniversityBeijing 100871China CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Yunnan Observatories Chinese Academy of SciencesKunming 650216China School of astronomy and Space Science Nanjing UniversityNanjing 210023China Key laboratory of Modern astronomy and astrophysics Nanjing UniversityNanjing 210023China

Fast radio bursts(FRBs)are short pulses observed in radio frequencies usually originating from cosmological distances.The discovery of FRB 200428 and its X-ray counterpart from the Galactic magnetar SGR J1935+2154suggests that at least some FRBs can be generated by magnetars.However,the majority of X-ray bursts from magnetars are not associated with radio emission.The fact that only in rare cases can an FRB be generated raises the question regarding the special triggering mechanism of FRBs.Here we report long time spin evolution of SGR J1935+2154 until the end of 2022.According to v and v,the spin evolution of SGR J1935+2154 could be divided into two stages.The first stage evolves relatively steady evolution until 2020 April 27.After the burst activity in2020,the spin of SGR J1935+2154 shows strong variations,especially for v.After the burst activity in 2022October,a new spin-down glitch with△v/v=(-7.2±0.6)×10^(-6)is detected around MJD 59876,which is the second event in SGR J1935+2154.At the end,spin frequency and pulse profile do not show variations around the time of FRB 200428 and radio bursts 221014 and 221021,which supply strong clues to constrain the trigger mechanism of FRBs or radio bursts.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(SGR J1935+2154) X-rays:bursts

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

快速射电暴的一种令人惊讶的随机行为

引用

Science Bulletin 2024年第11期69卷 1593-1594页

作者：张冰 The Nevada center for astrophysics University of NevadaLas Vegas 89154USA Department of Physics and astronomy University of NevadaLas Vegas 89154USA

Fast radio bursts(FRBs)are millisecond-duration,extremely luminous,radio bursting events originating from distant galaxies in the universe.Their physical origin remains a mystery.Discovered in 2007[1],these fascinating events have attracted great attention from the astronomical community,drawing the focus of both observers who develop advanced technology and gather data from powerful telescopes and theorists who explore various ideas and develop physical models to understand their underlying mechanism.

关键词： mechanism. galaxies origin

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：