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A review of geophysical studies on the Mongolian Plateau

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Earthquake Science 2024年第3期37卷 224-240页

作者： Lei Zhang Zhouchuan Huang Xiaodong Song Qingju Wu SinoProbe Laboratory School of Earth and Space SciencesPeking UniversityBeijing 100871China Hebei Hongshan national observatory on Thick Sediments and Seismic Hazards Peking UniversityBeijing 100871China School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

The Mongolian Plateau in Central Asia is an intracontinental tectonic system far from active plate *** its distance from these boundaries,the plateau is characterized by intense crustal deformation accompanied by voluminous Cenozoic volcanism and active modern ***,the intraplate deformation mechanism has long been debated owing to the scarcity of observations and contradictions between different *** recent years,growing geophysical studies have been conducted on the Mongolian Plateau,providing constraints on its lithospheric structure and ***,we review the geophysical research on the Mongolian Plateau over the last decade,including seismological,geodetic,gravity,magnetotelluric,and geodynamic *** review aims to(a)describe crustal and mantle structures based on multiscale seismic images;(b)describe deformation patterns based on seismic anisotropy,focal mechanisms,and global positioning system(GPS)observations;and(c)discuss the mechanisms behind intraplate deformation,volcanism,and seismic activity across the Mongolian *** images show that the crustal structure of the plateau has significant east-west *** blocks in the western Mongolian Plateau have thick crusts,including the Altai Mountains,Hovsgol Rift,and Hangay *** lithospheric deformation across the Mongolian Plateau has strong lateral variation,with NE-SW shortening in the Altai Mountains and W-E or NW-SE shear deformation in the Hangay Dome region and the eastern *** varied deformation may result from the superposition of multiple mechanisms,including far-field stress in the Altai Mountains,mantle upwelling,and mantle flow in the Hangay Dome ***,it is difficult to identify the geodynamics of the formation of the entire Mongolian Plateau because the deformation is too complicated,and the present models are not sufficient and are always ***,this review encompasses recent advances in seismic observa

关键词： Mongolian Plateau Central Asia seismic tomography crust-mantle structure intraplate deformation

Investigating Sulfur Chemistry in the HD163296 Disk

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Research in Astronomy and Astrophysics 2024年第7期24卷 218-228页

作者： Rong Ma Donghui Quan Yan Zhou Jarken Esimbek Dalei Li Xiaohu Li Xia Zhang Juan Tuo Yanan Feng Xinjiang Astronomical observatory Chinese Academy of Sciences University of Chinese Academy of Sciences Research Center for Intelligent Computing Platforms BinZhou University Key Laboratory of Radio Astronomy Chinese Academy of Sciences Xinjiang Key Laboratory of Radio Astrophysics

Sulfur chemistry in the formation process of low-mass stars and planets remains poorly *** protoplanetary disks are the birthplace of planets and its distinctive environment provides an intriguing platform for investigating models of sulfur *** analyzed the Atacama Large Millimeter/submillimeter Array observations of CS 7–6 transitions in the HD 163296 disk and performed astrochemical modeling to explore its sulfur *** simulated the distribution of sulfur-containing molecules and compared it with observationally deduced fractional column *** have found that the simulated column density of CS is consistent with the observationally deduced fractional column densities,while the simulated column density of C2S is lower than the observationally deduced upper limits on column *** results indicate that we have a good understanding of the chemical properties of CS and C2S in the *** also investigated the influence of the C/O ratio on sulfur-containing molecules and found that the column densities of SO,SO2,and H2S near the centra star are dependent on the C/O ***,we found that the N[CS]/N[SO]ratio can serve as a promising indicator of the disk’s C/O ratio in HD ***,the disk of HD 163296 provides a favorable environmen for the detection of sulfur-containing molecules.

关键词： Astrochemistry Molecular Processes Protoplanetary Disks

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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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 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa 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 *** 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 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** 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 *** 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 *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

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

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

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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

HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9

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Research in Astronomy and Astrophysics 2024年第1期24卷 292-299页

作者： Yan Guo C.Sengupta T.C.Scott P.Lagos Y.Luo Purple Mountain observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Institute of Astrophysics and Space Sciences(IA Porto) Rua das Estrelas4150-762PortoPortugal

We present resolved Giant Metrewave Radio Telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a Tidal Dwarf Galaxy(TDG) candidate. TDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large extended, unperturbed rotating H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. The quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved TDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the *** detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.

关键词： galaxies:abundances galaxies:dwarf galaxies:irregular radio lines:galaxies radio lines:ISM

Quantitative Analysis of Seeing with Height and Time at Muztagh-Ata Site Based on ERA5 Database

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Research in Astronomy and Astrophysics 2024年第1期24卷 87-95页

作者： Xiao-Qi Wu Cun-Ying Xiao Ali Esamdin Jing Xu Ze-Wei Wang Luo Xiao Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Astronomy Beijing Normal UniversityBeijing 100875China Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China

Seeing is an important index to evaluate the quality of an astronomical *** estimate seeing at the Muztagh-Ata site with height and time quantitatively,the European Centre for Medium-Range Weather Forecasts reanalysis database(ERA5)is *** calculated from ERA5 is compared consistently with the Differential Image Motion Monitor seeing at the height of 12 *** show that seeing decays exponentially with height at the Muztagh-Ata *** decays the fastest in fall in 2021 and most slowly with height in *** seeing condition is better in fall than in *** median value of seeing at 12 m is 0.89 arcsec,the maximum value is1.21 arcsec in August and the minimum is 0.66 arcsec in *** median value of seeing at 12 m is 0.72arcsec in the nighttime and 1.08 arcsec in the *** is a combination of annual and about biannual variations with the same phase as temperature and wind speed indicating that seeing variation with time is influenced by temperature and wind *** Richardson number Ri is used to analyze the atmospheric stability and the variations of seeing are consistent with Ri between *** quantitative results can provide an important reference for a telescopic observation strategy.

关键词： site testing atmospheric effects methods:data analysis telescopes Earth

Progress of International Meridian Circle Program

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空间科学学报 2024年第4期44卷 741-745页

作者： WANG Chi BLANC Michel ZHANG Shunrong DENARDINI Clezio Marcos LIU William SHEN Xuhui WU Jian XU Jiyao LI Hui ZHANG Qinghe REN Liwen ZHU Yajun LI Guozhu DING Zonghua LIU Zhengkuan YANG Fang national Space Science Center Chinese Academy of SciencesBeijing 100190 IRAP(CNRS-University Toulouse III-CNES) Toulouse 31400 Haystack observatory Massachusetts Institute of TechnologyMA 01886 Instituto Nacional de Pesquisas Espaciais São Josédos Campos(SP)Brazil 12227-010 China Research Institute of Radio wave Propagation Qingdao 266000 Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100083

In 2024,the Chinese Meridian Project(CMP)completed its construction,deploying 282 instruments across 31 *** achievement not only provides a robust foundation but also serves as a reference template for the International Meridian Circle Program(IMCP).The IMCP aims to integrate and establish a comprehensive network of ground-based monitoring stations designed to track the propagation of space weather events from the Sun to ***,it monitors various disturbances generated within the Earth system that impact *** the past two years,significant progress has been made on the *** particular,the second phase of construction for the China-Brazil Joint Laboratory for Space Weather has been completed,and the North Pole and Southeast Asia networks are under active *** 2024 IMCP joint observation campaign was successfully *** facilitate these developments,the scientific program committee of IMCP was established,following the success of 2023 IMCP workshop and the space weather school,which was co-hosted with the Asia-Pacific Space Cooperation Organization(APSCO)and sponsored by Chinese Academy of Sciences(CAS)and Scientific Committee on solar-Terrestrial Physics(SCOSTEP).Preparations are now underway for the 2024 workshop in collaboration with the national Institute for Space Research(INPE)in Brazil.

关键词： Chinese Meridian Project(CMP) International Meridian Circle Program(IMCP) China-Brazil Joint Laboratory for Space Weather North Pole and Southeast Asia networks

Understanding the Impact of H2 Diffusion Energy on the Formation Efficiency of H2 on the Interstellar Dust Grain Surface

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Research in Astronomy and Astrophysics 2024年第9期 192-200页

作者： Xiaoying Guo Wasim Iqbal Qiang Chang Xiao-Hu Li School of Physics and Optoeletronic Engineering Shandong University of Technology Xinjiang Astronomical observatory Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences

We use microscopic Monte Carlo simulation techniques to investigate the impact of H2diffusion energy on the recombination efficiency of H2on interstellar dust grain surfaces under diffuse and translucent cloud *** constructed five models representing different possible conditions encountered by adsorbed H and H2on interstellar dust *** implemented adsorption sites with multiple binding energies for surface species;the Encounter-Desorption mechanism was also *** study focused on silicate surfaces in diffuse clouds and water ice surfaces in translucent *** results show that the recombination efficiency of H2on dust surfaces decreases as H2diffusion energy *** interesting finding of this work is that considering different binding sites for H and H2gives rise to multiple steady phases,during which the recombination efficiency remains constant with a change in H2diffusion energy.

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Raindrop Size Distributions in the Zhengzhou Extreme Rainfall Event on 20 July 2021:Temporal-Spatial Variability and Implications for Radar QPE

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Journal of Meteorological Research 2024年第3期38卷 489-503页

作者： Liman CUI Haoran LI Aifang SU Yang ZHANG Xiaona LYU Le XI Yuanmeng ZHANG Henan Key Laboratory of Agrometeorological Support and Applied Technique China Meteorological AdministrationZhengzhou450003China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing100081China Henan Meteorological observatory Zhengzhou450003China

In this study,a regional Parsivel OTT disdrometer network covering urban Zhengzhou and adjacent areas is employed to investigate the temporal-spatial variability of raindrop size distributions(DSDs)in the Zhengzhou extreme rainfall event on 20 July *** rain rates observed by disdrometers and rain gauges from six operational sites are in good agreement,despite significant site-to-site variations of 24-h accumulated rainfall ranging from 198.3 to 624.1 *** Parsivel OTT observations show prominent temporal-spatial variations of DSDs,and the most drastic change was registered at Zhengzhou Station where the record-breaking hourly rainfall of 201.9 mm over 1500-1600 LST(local standard time)was *** hourly rainfall is characterized by fairly high concentrations of large raindrops,and the mass-weighted raindrop diameter generally increases with the rain rate before reaching the equilibrium state of DSDs with the rain rate of about 50 mm h^(−1).Besides,polarimetric radar observations show the highest differential phase shift(K_(dp))and differential reflectivity(Z_(dr))near surface over Zhengzhou Station from 1500 to 1600 *** light of the remarkable temporal-spatial variability of DSDs,a reflectivity-grouped fitting approach is proposed to optimize the reflectivity-rain rate(Z-R)parameterization for radar quantitative precipitation estimation(QPE),and the rain gauge measurements are used for *** results show an increase of mean bias ratio from 0.57 to 0.79 and a decrease of root-mean-square error from 23.69 to 18.36 for the rainfall intensity above 20.0 mm h^(−1),as compared with the fixed Z-R *** study reveals the drastic temporal-spatial variations of rain microphysics during the Zhengzhou extreme rainfall event and warrants the promise of using reflectivity-grouped fitting Z-R relationships for radar QPE of such events.

关键词： extreme rainfall raindrop size distribution radar quantitative precipitation estimation(QPE)