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CO observations of massive star forming regions at different evolutionary phases

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2, XU Ye1,3, SHEN Zhiqiang1,3 & LI Jingjing1,2 1. shanghai Astronomical Observatory, chinese academy of sciences, shanghai 20003., china 2. Graduate school of the chinese academy of sciences, beijing 100034, china 3. joint institute for galaxy and cosmology, shanghai Astronomical Observatory and the University of Science and Technology of china, shanghai 20003., china shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate school of the chinese academy of sciences Beijing 100034 China joint institute for galaxy cosmology Shanghai Astronomical Observatory the University of Science Technology of china Shanghai 200030 China

The 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13CO cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2O masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 22566+5828 in the observing field of S152/S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2O maser simulta- neously.

关键词： star formation cloud core outflow H2O maser

Multi-epoch X-ray observations of the narrow-line Seyfert 1 galaxy SDSS J160508.87+3.3.21.4 with XMM-Newton

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 207-211页

作者： AI YanLi1,2,3,YUAN WeiMin1,2,ZHOU HongYan4,5 & WANG JianGuo1,2,3 1 National Astronomical Observatories/Yunnan Observatory,chinese academy of sciences,Kunming 650011,china 2 Key Laboratory for the Structure and Evolution of Celestial Objects,chinese academy of sciences,Kunming 650011,china 3 Graduate University of the chinese academy of sciences,beijing 100049,china 4 Center for Astrophysics,University of Science and Technology of china,Hefei 230026,china 5 joint institute of Galaxies and cosmology,shao and USTC,shanghai 20003.,china 1. National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China 2. Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China 3. Graduate University of the chinese academy of sciences Beijing 100049 China 4. Center for Astrophysics University of Science and Technology of China Hefei 230026 China 5. joint institute of Galaxies and cosmology SHAO and USTC Shanghai 200030 China

We present results of multi-epoch XMM-Newton observations separated by several years of the narrow-line Seyfert 1(NLS1) galaxy,SDSS J160508.87+*** NLS1 showed X-ray flux variations on timescales of years as well as low amplitude variations on timescales as short as hours,while the X-ray spectral shape remained essentially *** spectrum shows a significant soft X-ray *** model of reflection from an ionized disc,that is dominant in the whole XMM-Newton bandpass,provides the best description of the observed spectra for all the observations,though alternatives such as Compton scattering(T-0.25 keV) cannot be ruled out in a statistical *** the disc reflection model,the observed variations may originate either from the change in the reflection fraction,or from the variability of the intrinsic X-ray luminosity.

关键词： galaxies:active Seyfert X-rays individual

Scalar dark energy models and scalar–tensor gravity:theoretical explanations for the accelerated expansion of the present Universe

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Communications in Theoretical Physics 2024年第10期76卷 160-189页

作者： Peixiang Ji Lijing shao Department of Astronomy School of Physics Peking University Kavli institute for Astronomy and Astrophysics Peking University National Astronomical Observatories Chinese Academy of Sciences

The reason for the present accelerated expansion of the Universe stands as one of the most profound questions in the realm of science, with deep connections to both cosmology and fundamental physics. From a cosmological point of view, physical models aimed at elucidating the observed expansion can be categorized into two major classes: dark energy and modified gravity. We review various major approaches that employ a single scalar field to account for the accelerating phase of our present Universe. Dynamic system analysis was employed in several important models to find cosmological solutions that exhibit an accelerating phase as an *** scalar field models of dark energy, we consistently focused on addressing challenges related to the fine-tuning and coincidence problems in cosmology, as well as exploring potential solutions to them. For scalar–tensor theories and their generalizations, we emphasize the importance of constraints on theoretical parameters to ensure overall consistency with experimental tests. Models or theories that could potentially explain the Hubble tension are also emphasized throughout this review.

关键词： cosmology dark energy dynamic system modified gravity quintessence

The Clumpy Structure of Five Star-bursting Dwarf Galaxies in the MaNGA Survey

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Research in Astronomy and Astrophysics 2024年第2期24卷 83-103页

作者： Mengting Ju Jun Yin Lei Hao Chenxu Liu Chao-Wei Tsai Junfeng Wang Zhengyi shao Shuai Feng Yu Rong Key Laboratory for Research in Galaxies and cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China University of chinese academy of sciences Beijing 100049China Key Lab for Astrophysics Shanghai 200034China South-Western institute for Astronomy Research Yunnan UniversityKunming 650500China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Astronomy Physics BuildingXiamen UniversityXiamenFujian 361005China College of Physics Hebei Normal UniversityShijiazhuang 050024China Hebei Key Laboratory of Photophysics Research and Application Shijiazhuang 050024China Department of Astronomy University of Science and Technology of ChinaHefei 230026China

The star-forming clumps in star-bursting dwarf galaxies provide valuable insights into understanding the evolution of dwarf *** this paper,we focus on five star-bursting dwarf galaxies featuring off-centered clumps in the Mapping Nearby Galaxies at Apache Point Observatory *** the stellar population synthesis software Fitting Analysis using Differential evolution Optimization,we obtain the spatially resolved distribution of the star formation history,which allows us to construct the g-band images of the five galaxies at different *** images can help us to probe the evolution of the morphological structures of these *** images of a stellar population older than 1 Gyr are typically smooth,images of a stellar population younger than 1 Gyr reveal significant clumps,including multiple clumps which appear at different locations and even different *** study the evolutionary connections of these five galaxies to other dwarf galaxies before their star-forming clumps appear,we construct the images of the stellar populations older than three age nodes,and define them to be the images of the"host"*** find that the properties such as the central surface brightness and the effective radii of the hosts of the five galaxies are in between those of dwarf ellipticals(dEs)and dwarf irregulars(dIrrs),with two clearly more similar to dEs and one more similar to *** the five galaxies,8257-3704 is particularly interesting,as it shows a previous starburst event that is not quite visible from its gri image,but only visible from images of the stellar population at a few hundred million *** star-forming clump associated with this event may have appeared at around 600 Myr ago and disappeared at around 40 Myr ago.

关键词： galaxies dwarf-galaxies evolution-galaxies formation-galaxy structure

HiFAST:An HIdata calibration and imaging pipeline for FAST

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Science china(Physics,Mechanics & Astronomy) 2024年第5期67卷 182-199页

作者： Yingjie Jing Jie Wang Chen Xu Ziming Liu Qingze Chen Tiantian Liang Jinlong Xu Yixian Cao Jing Wang Huijie Hu Chuan-Peng Zhang Qi Guo Liang Gao Mei Ai Hengqian Gan Xuyang Gao Jinlin Han Ligang Hou Zhipeng Hou Peng Jiang Xu Kong Fujia Li Zerui Liu Li shao Hengxing Pan Jun Pan Lei Qian Jinghai Sun Ningyu Tang Qingliang Yang Bo Zhang Zhiyu Zhang Ming Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 02206China school of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 55000China Max Planck institute for Extraterrestrial Physics Garching 85748Germany Kavli institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China institute of Computational cosmology Department of PhysicsUniversity of DurhamDurham DHI 3LEUK CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Deep Space Exploration Laboratory/Department of Astronomy University of Science and Technology of ChinaHefei 230026China school of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Astrophysics Department of PhysicsUniversity of OxfordOxford OX/3RHUK College of Earth sciences Guilin University of TechnologyGuilin 541004China Department of Physics Anhui Normal UniversityWuhu 241002China school of Astronomy and Space Science Nanjing UniversityNanjing 210023China Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityNanjing 20023China

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)has the largest aperture and a 19-beam L-band receiver,making it powerful for investigating the neutral hydrogen atomic gas(HI)in the *** present HiFAST(https://***),a dedicated,modular,and self-contained calibration and imaging pipeline for processing the H?data of *** pipeline consists of frequency-dependent noise diode calibration,baseline fitting,standing wave removal using an FFT-based method,flux density calibration,stray radiation correction,and gridding to produce data *** modules can be combined as needed to process the data from most FAST observation modes:tracking,drift scanning,On-The-Fly mapping,and most of their *** HiFAST,the root-mean-square(RMS)noises of the calibrated spectra from all 19 beams were only slightly(~5%)higher than the theoretical *** results for the extended source M33 and the point sources are consistent with the results from *** moment maps(0,1 and 2)of M33 agree well with the results from the Arecibo galaxy Environment Survey(AGES)with a fractional difference of less than 10%.For a common sample of 221 sources with signal-to-noise ratio S/N>10 from the Arecibo Legacy Fast ALFA(ALFALFA)survey,the mean value of fractional difference in the integrated flux density,Sint,between the two datasets is approximately 0.005%,with a dispersion of 15.4%.Further checks on the integrated flux density of 23 sources with seven observations indicate that the variance in the flux density of the source with luminous objects(Sint>2.5 Jy km s-1)is less than 5%.Our tests suggest that the FAST telescope,with the efficient,precise,and user-friendly pipeline HiFAST,will yield numerous significant scientific findings in the investigation of the H?in the universe.

关键词： fractional luminous correction

Luminosity Function of the Cluster of Galaxies Abell 566

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chinese Journal of Astronomy and Astrophysics 2007年第5期7卷 620-628页

作者： Quan-Bao Xiao Zheng-Yi shao Xu Zhou shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 joint institute for galaxy ＆ cosmology Chinese Academy of Sciences Shanghai 200030 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We investigate the Luminosity Function （LF） of the cluster of galaxies Abell 566. The photometric data of 15 intermediate-bands are obtained from the beijing-Arizona- Taiwan-Connecticut （BATC） photometric sky survey. For each of the 15 wavebands, the LF of cluster galaxies is well modelled by the Schechter function, with characteristic luminosities from -18.0 to -21.9 magnitude, from the α- to the p-band. Morphological dependence of the LF is investigated by separating the cluster members into ＇red＇ and ＇blue＇ subsamples. It is clear that late type galaxies have a steeper shape of LF than the early type galaxies. We also divided the sample galaxies by their local environment. It was found that galaxies in the sparser region have steeper shape of LF than galaxies in the denser region. Combining the results of morphological and environmental dependence of LFs, we show that Abell 566 is a well relaxed cluster with positive evidence of galaxy interaction and merger, and excess number of bright early type galaxies located in its denser region.

关键词： galaxy cluster individual Abell 566 -- galaxy photometry -- galaxy lumi- nosity function

The Inclination, Pitch Angle and Forbidden Radius of Spiral Arms of PGC 35105

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chinese Journal of Astronomy and Astrophysics 2006年第2期6卷 175-180页

作者： Tao Hu Zheng-Yi shao Qiu-He Peng Department of Astronomy Nanjing University Nanjing 210093 shanghai Astronomical Observatory Chinese-Academy of Sciences Shanghai 200030 joint institute for Galaxies and cosmology Chinese Academy of Sciences Shanghai 200030 joint Astrophysics Center of chinese academy of sciences-Peking University Beijing 100871 The Open Laboratory of Cosmic Ray and High Energy Astrophysics Chinese Academy otSciences Beijing 100049

We have studied some properties including surface brightness in the u, g, r, i, and z bands of the nearly face-on galaxy PGC 35105. By subtracting a model surface brightness distribution from the observed image we obtain the residual image that shows only the spiral arms freed from the contamination by the bulge. From this we measured the the inclination, pitch angle, and forbidden radius （identified with the innermost point of the arm） for each of the two arms; and that for each of the five observing bands. We found these three parameters are largely independent of the observing band.

关键词： galaxies: fundamental parameters - galaxies: spiral - galaxies: structure - galaxies: surface brightness - galaxies: individual (PGC 35105)

Subhalo Abundance and Satellite Spatial Distribution in Milky Way-Andromeda-like Paired Haloes

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Research in Astronomy and Astrophysics 2022年第12期22卷 344-352页

作者： Kemeng Li Shi shao Ping He Qing Gu Jie Wang College of Physics Jilin UniversityChangchun 130012China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Center for High Energy Physics Peking UniversityBeijing 100871China school of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We study the subhalo and satellite populations in haloes similar to the Milky Way(MW)-Andromeda paired configuration in the Millennium II and P-Millennium *** find subhaloes are 5%–15%more abundant in paired haloes than their isolated counterparts that have the same halo mass and large-scale environmental *** haloes tend to reside in a more isotropic environment than isolated haloes,the shear tensor of their large-scale tidal field is possibly responsible for this *** also study the thickness of the spatial distribution of the top 11 most massive satellite galaxies obtained in the semi-analytic galaxy sample constructed from the Millennium II ***,satellites that have lost their host subhaloes due to the resolution limit of the simulation have been taken into *** a result,we find that the difference in the distribution of the satellite thickness between isolated and paired haloes is indistinguishable,which suggests that the paired configuration is not responsible for the observed plane of satellites in the *** results in this study indicate the paired configuration could bring some nonnegligible effect on the subhalo abundance in the investigation of the MW's satellite problems.

关键词： galaxies:abundances galaxies:halos galaxies:structure (galaxies:)Local Group (cosmology:)dark matter methods:numerical

HiFAST:An H?data calibration and imaging pipeline for FAST

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Science china(Physics,Mechanics & Astronomy) 2024年第5期Mechanics & Astronomy) .卷 186-203页

作者： Yingjie Jing Jie Wang Chen Xu Ziming Liu Qingze Chen Tiantian Liang Jinlong Xu Yixian Cao Jing Wang Huijie Hu Chuan-Peng Zhang Qi Guo Liang Gao Mei Ai Hengqian Gan Xuyang Gao Jinlin Han Ligang Hou Zhipeng Hou Peng Jiang Xu Kong Fujia Li Zerui Liu Li shao Hengxing Pan Jun Pan Lei Qian Jinghai Sun Ningyu Tang Qingliang Yang Bo Zhang Zhiyu Zhang Ming Zhu National Astronomical Observatories Chinese Academy of Sciences institute for Frontiers in Astronomy and Astrophysics Beijing Normal University school of Astronomy and Space Science University of Chinese Academy of Sciences Guizhou Radio Astronomical Observatory Guizhou University Max Planck institute for Extraterrestrial Physics Kavli institute for Astronomy and Astrophysics Peking University institute of Computational cosmology Department of PhysicsUniversity of Durham CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of Sciences Deep Space Exploration Laboratory/Department of Astronomy University of Science and Technology of China school of Astronomy and Space Science University of Science and Technology of China Astrophysics Department of PhysicsUniversity of Oxford College of Earth sciences Guilin University of Technology Department of Physics Anhui Normal University school of Astronomy and Space Science Nanjing University Key Laboratory of Modern Astronomy and Astrophysics Nanjing University

The Five-hundred-meter Aperture Spherical radio Telescope（FAST） has the largest aperture and a 19-beam L-band receiver,making it powerful for investigating the neutral hydrogen atomic gas（H?） in the *** present HiFAST（https://***）,a dedicated,modular,and self-contained calibration and imaging pipeline for processing the H?data of *** pipeline consists of frequency-dependent noise diode calibration,baseline fitting,standing wave removal using an FFT-based method,flux density calibration,stray radiation correction,and gridding to produce data *** modules can be combined as needed to process the data from most FAST observation modes:tracking,drift scanning,On-The-Fly mapping,and most of their *** HiFAST,the root-mean-square（RMS） noises of the calibrated spectra from all 19 beams were only slightly（～5%） higher than the theoretical *** results for the extended source M33 and the point sources are consistent with the results from *** moment maps（0,1 and 2） of M33 agree well with the results from the Arecibo galaxy Environment Survey（AGES） with a fractional difference of less than 10%.For a common sample of 221 sources with signal-to-noise ratio S/N>10 from the Arecibo Legacy Fast ALFA（ALFALFA） survey,the mean value of fractional difference in the integrated flux density,Sint,between the two datasets is approximately 0.005%,with a dispersion of 15.4%.Further checks on the integrated flux density of 23 sources with seven observations indicate that the variance in the flux density of the source with luminous objects(Sint>2.5 Jy km s-1) is less than 5%.Our tests suggest that the FAST telescope,with the efficient,precise,and user-friendly pipeline HiFAST,will yield numerous significant scientific findings in the investigation of the H? in the universe.

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