检索结果-南通市图书馆

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

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 *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** 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 *** 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■*** 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 *** 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 *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** 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

Lossless Compression Method for the Magnetic and Helioseismic Imager(MHI)Payload

引用

Research in astronomy and Astrophysics 2024年第4期24卷 214-221页

作者： Li-Yue Tong Jia-Ben Lin Yuan-Yong Deng Kai-Fan Ji Jun-Feng Hou Quan Wang Xiao Yang national astronomical observatories Chinese Academy of SciencesBeijing 100101China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China School of astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Yunnan observatories Chinese Academy of SciencesKunming 650216China

The Solar Polar-orbit Observatory(SPO),proposed by Chinese scientists,is designed to observe the solar polar regions in an unprecedented way with a spacecraft traveling in a large solar inclination angle and a small ***,one of the most significant challenges lies in ultra-long-distance data transmission,particularly for the Magnetic and Helioseismic Imager(MHI),which is the most important payload and generates the largest volume of data in *** this paper,we propose a tailored lossless data compression method based on the measurement mode and characteristics of MHI *** background out of the solar disk is removed to decrease the pixel number of an image under *** predictive coding methods are combined to eliminate the redundancy utilizing the correlation(space,spectrum,and polarization)in data set,improving the compression *** results demonstrate that our method achieves an average compression ratio of *** compression time is also less than the general observation *** method exhibits strong feasibility and can be easily adapted to MHI.

关键词： methods:data analysis techniques:image processing Sun:magnetic fields Sun:photosphere

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

Implications of the Stellar Mass Density of High-z Massive Galaxies from JWST on Warm Dark Matter

引用

Research in astronomy and Astrophysics 2024年第1期24卷 128-134页

作者： Hengjie Lin Yan Gong Bin Yue Xuelei Chen national astronomical observatories Chinese Academy of SciencesBeijing 100101China university of Chinese Academy of Sciences Beijing 100049China Science center for China Space Station Telescope National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Department of Physics College of SciencesNortheastern UniversityShenyang 110819China center for High Energy Physics Peking UniversityBeijing 100871China

A significant excess of the stellar mass density at high redshift has been discovered from the early data release of James Webb Space Telescope(JWST),and it may require a high star formation ***,this will lead to large number density of ionizing photons in the epoch of reionization(EoR),so that the reionization history will be changed,which can arise tension with the current EoR *** dark matter(WDM),via the free streaming effect,can suppress the formation of small-scale structure as well as low-mass *** provides an effective way to decrease the ionizing photons when considering a large star formation efficiency in high-z massive galaxies without altering the cosmic reionization *** the other hand,the constraints on the properties of WDM can be derived from the JWST *** this work,we study WDM as a possible solution to reconcile the JWST stellar mass density of high-z massive galaxies and reionization *** find that,the JWST high-z comoving cumulative stellar mass density alone has no significant preference for either CDM or WDM *** using the observational data of other stellar mass density measurements and reionization history,we obtain that the WDM particle mass with mw=0.51_(-0.12)^(+0.22) keV and star formation efficiency parameter f_(*)^(0)> 0.39 in 2σ confidence level can match both the JWST high-z comoving cumulative stellar mass density and the reionization history.

关键词： Cosmology (cosmology:)dark matter (cosmology:)large-scale structure of universe

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

Close Major-merger Pairs at z=0: Star-forming Galaxies with Pseudobulges

引用

Research in astronomy and Astrophysics 2024年第5期24卷 35-60页

作者：何川徐聪 Ute Lisenfeld 戴昱方陶陶黄家声王炜余清正 Chinese Academy of Sciences South America center for astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Departamento de Física Teórica y del Cosmos Universidad de Granada18071 GranadaSpain Instituto Carlos I de Física Téorica y Computacional Facultad de Ciencias18071 GranadaSpain Department of astronomy Xiamen UniversityXiamen 361005China CAS Key Laboratory of Optical astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n2σ) mean of specific star formation rate (sSFR) enhancement (sSFR_(enh)=0.33±0.07 versus sSFR_(enh)=0.12±0.06) and broader scatter (by~1 dex).The eight SFGs that have the highest sSFR_(enh)in the sample all have pseudobulges.A majority (69%) of paired SFGs with strong enhancement (having sSFR more than5 times the median of the control galaxies) have *** Spitzer data show that the pseudobulges in these galaxies are tightly linked to nuclear/circum-nuclear *** SFGs in S+S and in S+E pairs have significantly (>3σ) different sSFR enhancement,with the means of sSFR_(enh)=0.45±0.08 and-0.04±*** find a decrease in the sSFR enhancements with the density of the environment for SFGs with *** a high fraction (5/11) of pseudobulge SFGs in S+E pairs are in rich groups/clusters (loca density N_(1Mpc)≥7),the dense environment might be the cause for their low s SFR_(enh).

关键词： galaxies evolution-galaxies interactions-galaxies star formation-galaxies structure-galaxies bulges-galaxies photometry

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 Galactic Halo with RR Lyrae Stars. VI. The Radial Velocity Curve Templates of RRc Stars

引用

Research in astronomy and Astrophysics 2024年第7期24卷 121-137页

作者： Yue Huang Min Fang Gaochao Liu Xianzhong Zheng Sarah Ann Bird Yang Huang Jianrong Shi Jiangtao Wang Huawei Zhang Haijun Tian Haotong Zhang College of Science China Three Gorges University center for astronomy and Space Sciences China Three Gorges University Purple Mountain Observatory Chinese Academy of Sciences School of astronomy and Space Science University of Science and Technology of China School of astronomy and Space Science University of Chinese Academy of Sciences CAS Key Laboratory of Optical astronomy National Astronomical Observatories Department of astronomy School of PhysicsPeking University Kavli Institute for astronomy and Astrophysics Peking University School of Sciences Hangzhou Dianzi University

We present radial velocity（RV） curve templates of RR Lyrae first-overtone（RRc） stars constructed with the Mg I b triplet and Hα lines using time-domain Medium-Resolution Survey spectra of seven RRc stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） Data Release 9. Additionally, we derive the relation between the stellar RV curve amplitudes and g-band light curve amplitudes from Zwicky Transient Facility（ZTF）public survey. For those RRc stars without ZTF g-band light curves, we provide the conversions from the light curve amplitudes in ZTF r-and i-bands, Gaia G-band, and V-band from the All-Sky Automated Survey for Supernovae to those in ZTF g-band. We validate our RV curve templates using the RRc star SV Scl and find the uncertainties of systemic RV are less than 2.11 km s-1and 6.08 km s-1based on the Mg I b triplet and Hα lines,respectively. We calculate the systemic RVs of 30 RRc stars using the RV curve templates constructed with the Mg I b triplet and Hα lines and find the systemic RVs are comparable with each other. This RV curve template will be particularly useful for obtaining the systemic RV of RRc using the LAMOST spectroscopy.

关键词： Stars stars: variables: RR Lyrae techniques: radial velocities

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 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24卷 1-6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 ObservatoriesChinese Academy of SciencesChangchun 130117China national astronomical observatories Chinese Academy of SciencesBeijing 100101China university of Chinese Academy of Sciences Beijing 101408China astronomy Department Beijing Normal UniversityBeijing 100875China International center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Nanjing Institute of astronomical Optics and Technology Chinese Academy of SciencesNanjing 210042China

Lunar optical polarization is a fascinating phenomenon that occurs when sunlight reflects off the surface of the Moon and becomes *** study employs a novel split-focus plane polarimetric camera to conduct the initial white light polarimetric observations on the near side of the *** obtained the linear degree of polarization(DOP)parameters of white light by observation from the eastern and western hemispheres of the *** findings indicate that the white light polarization is lower in the lunar highland than in the lunar maria *** 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 *** study may serve as a new diagnostic tool for the Moon.

关键词： techniques:photometric polarization methods:observational 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

Digitization of astronomical Photographic Plates of China and Astrometric Measurement of Single-exposure Plates

引用

Research in astronomy and Astrophysics 2024年第5期24卷 103-116页

作者：商正君于涌王亮亮杨美婷杨静沈世银刘敏徐权峰崔辰州樊东卫唐正宏赵建海 Shanghai astronomical Observatory Chinese Academy of SciencesShanghai 200030China university of Chinese Academy of Sciences Beijing 100049China Key Lab for Astrophysics Shanghai200234China national astronomical observatories Chinese Academy of SciencesBeijing 100101China national astronomical Data center Chinese Academy of SciencesBeijing 100101China

From the mid-19th century to the end of the 20th century, photographic plates served as the primary detectors for astronomical observations. astronomical photographic observations in China began in 1901, and over a century, a total of approximately 30,000 astronomical photographic plates were captured. These historical plates play an irreplaceable role in conducting long-term, time-domain astronomical research. To preserve and explore these valuable original astronomical observational data, Shanghai astronomical Observatory has organized the transportation of plates, taken during nighttime observations from various stations across the country, to the Sheshan Plate Archive for centralized preservation. For the first time, plate information statistics were calculated. On this basis, the plates were cleaned and digitally scanned, and finally digitized images were acquired for 29,314 plates. In this study, using Gaia DR2 as the reference star catalog, astrometric processing was carried out successfully on 15,696 single-exposure plates, including object extraction, stellar identification,and plate model computation. As a result, for long focal length telescopes, such as the 40 cm double-tube refractor telescope, the 1.56 m reflector telescope at Shanghai astronomical Observatory, and the 1m reflecting telescope at Yunnan astronomical Observatory, the astrometric accuracy obtained for their plates is approximately 0."1–0."3. The distribution of astrometric accuracy for medium and short focal length telescopes ranges from 0."3 to 1."0. The relevant data of this batch of plates, including digitized images and a stellar catalog of the plates, are archived and released by the national astronomical Data center. Users can access and download plate data based on keywords such as station, telescope, observation year, and observed celestial coordinates.

关键词： methods data analysis-techniques image processing-astronomical databases miscellaneous-astrometry

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

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 38-51页

作者： Xiaopeng Liu Hao Tian Wenyuan Cui Linlin Li Jiaming Liu Zhenyan Huo Yawei Gao Department of Physics Hebei Normal UniversityShijiazhuang 050024China Guo Shoujing Institute for astronomy Hebei Normal UniversityShijiazhuang 050024China Key Laboratory of Space astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Institute for Frontiers in astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China

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 *** scale length decreases versus the azimuthal angleΦ,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 *** scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around h_(s)=130 *** distribution of the displaceeent of the disk plane Z_(0)also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid *** 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： Galaxy:disk galaxies:spiral stars:early-type stars:massive

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

Scintillation Arc from FRB 20220912A

引用

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 *** arc indicates that the scintillation is caused by a highly localized *** analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy *** present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or *** 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

Long-term Variation of the Solar Polar Magnetic Fields at Different Latitudes

引用

Research in astronomy and Astrophysics 2024年第7期24卷 193-200页

作者： Shuhong Yang Jie Jiang Zifan Wang Yijun Hou Chunlan Jin Qiao Song Yukun Luo Ting Li Jun Zhang Yuzong Zhang Guiping Zhou Yuanyong Deng Jingxiu Wang national astronomical observatories Chinese Academy of Sciences School of astronomy and Space Science University of Chinese Academy of Sciences State Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of Sciences School of Space and Environment Beihang University Key Laboratory of Space Weather National Satellite Meteorological Center (National Center for Space Weather) Innovation center for FengYun Meteorological Satellite (FYSIC) School of Physics and Materials Science Anhui University

The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind. However, because our view of the Sun is limited in the ecliptic plane, the polar regions remain largely uncharted. Using the high spatial resolution and polarimetric precision vector magnetograms observed by Hinode from 2012 to 2021, we investigate the long-term variation of the magnetic fields in polar caps at different *** Hinode magnetic measurements show that the polarity reversal processes in the north and south polar caps are non-simultaneous. The variation of the averaged radial magnetic flux density reveals that, in each polar cap, the polarity reversal is completed successively from the 70° latitude to the pole, reflecting a poleward magnetic flux migration therein. These results clarify the polar magnetic polarity reversal process at different latitudes.

关键词： dynamo Sun: magnetic fields Sun: photosphere

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

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：