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Capture Efficiency Analysis in the Circular Restricted Three-body Problem

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Research in astronomy and Astrophysics 2024年第5期24卷 198-210页

作者： Yu-Xuan Miao Xi-Yun Hou department of astronomy and space Science Nanjing UniversityNanjing 210023China Institute of space Environment and Astrodynamics Nanjing UniversityNanjing 210023China Key Laboratory of Modern astronomy and Astrophysics Ministry of EducationNanjing 210023China

Temporary capture efficiency is studied in the framework of the circular restricted three-body problem in two ***, a non-uniform distribution of test particles around the secondary's orbit is obtained by fully accounting the secondary's gravitational influence. Second, the capture efficiency is computed based on the non-uniform distribution. Several factors influencing the result are discussed. By studying the capture efficiency in the circular restricted three-body problem of different mass ratios, a power-law relation between the capture efficiency(p) and the mass ratio(μ) is established, which is given by p ≈ 0.27 × μ^(0.53), within the range of 3.0035 ×10^(-6)≤ μ ≤ 3.0034 × 10^(-5). Taking the Sun–Earth system as an example, the influence from the orbit eccentricity of the secondary on the non-uniform distribution and the capture efficiency is studied. Our studies find that the secondary's orbit eccentricity has a negative influence on the capture efficiency.

关键词： methods numerical-celestial mechanics-planets and satellites dynamical evolution and stability

Simulation study of the performance of the Very Large Area gamma-ray space Telescope

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Nuclear Science and Techniques 2024年第9期35卷 1-17页

作者： Xu Pan Wei Jiang Chuan Yue Shi-Jun Lei Yu-Xin Cui Qiang Yuan 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

The Very Large Area gamma-ray space Telescope(VLAST)is a mission concept proposed to detect gamma-ray photons through both Compton scattering and electron–positron pair production mechanisms,thus enabling the detection of photons with energies ranging from MeV to *** project aims to conduct a comprehensive survey of the gamma-ray sky from a low-Earth orbit using an anti-coincidence detector,a tracker detector that also serves as a low-energy calorimeter,and a high-energy imaging *** developed a Monte Carlo simulation application of the detector using the GEANT4 toolkit to evaluate the instrument performance,including the effective area,angular resolution,and energy resolution,and explored specific optimizations of the detector *** simulation-based analysis indicates that the current design of the VLAST is physically feasible,with an acceptance above 10 m^(2)sr which is four times larger than that of the Fermi-LAT,an energy resolution better than 2%at 10 GeV,and an angular resolution better than 0.2◦at 10 *** VLAST project promises to make significant contributions to the field of gamma-ray astronomy and enhance our understanding of the cosmos.

关键词： space astronomy Gamma-ray telescope Calorimeter Monte Carlo simulation

Forecast of cosmological constraints with superluminous supernovae from the Chinese space Station Telescope

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Science China(Physics,Mechanics & astronomy) 2024年第10期67卷 128-138页

作者： Xuan-Dong Jia Jian-Ping Hu Fa-Yin Wang Zi-Gao Dai School of astronomy and space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210093China department of astronomy University of Science and Technology of ChinaHefei 230026China

Superluminous supernovae(SLSNe)are a class of intense celestial events that can be standardized for measuring cosmological parameters,bridging the gap between type Ia supernovae and the cosmic microwave *** this work,we discuss the cosmological applications of SLSNe from the Chinese space Station Telescope(CSST).Our estimation suggests that SLSNe rate is biased tracing the cosmic star formation rate,exhibiting a factor of(1+z)^(1.2).We futher predict that CSST is poised to observe~360 SLSNe in the 10 square degrees ultra-deep field survey within a span of 2.5 years.A stringent constraint on cosmological parameters can be derived from their peak-color *** is anticipated to uncover a substantial number of SLSNe,contributing to a deeper understanding of their central engines and shedding light on the nature of dark energy at high redshifts.

关键词： supernovae cosmology cosmological constant

The Multi-parameter Test of Gravitational Wave Dispersion with Principal Component Analysis

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Research in astronomy and Astrophysics 2024年第5期24卷 140-150页

作者： Zhi-Chu Ma Rui Niu Wen Zhao CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of astronomy and space Sciences University of Science and Technology of ChinaHefei 230026China

In this work, we consider a conventional test of gravitational wave(GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity(GR)along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis(PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multiparameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.

关键词： gravitational waves-gravitation-black hole physics

Recent Progresses of the DAMPE Mission

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空间科学学报 2024年第4期44卷 633-642页

作者： CHANG Jin Key Laboratory of Dark Matter and space astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210033 School of astronomy and space Science University of Science and Technology of ChinaHefei 230026

The DArk Matter Particle Explorer(DAMPE)is a space high-energy particle andγ-ray detector whose major scientific goals are the indirect detection of dark matter particles,the origin of cosmic rays and highenergyγ-ray *** its successful launch in December 2015,the DAMPE has been operated smoothly in orbit for more than 8 *** direct measurements of the boron-to-carbon and boron-to-oxygen flux ratios,and the proton+Helium spectrum up to 316 TeV have been obtained,revealing new spectral features with very high *** search results ofγ-ray spectral line and fractionally charged particles indicate a good potential of DAMPE for indirect dark matter detection and new physical discovery in *** DAMPE measurements are expected to significantly advance our understanding of the fundamental problems in astroparticle physics.

关键词： DAMPE Dark matter Indirect detection Cosmic rays

On the Performances of Estimating Stellar Atmospheric Parameters from CSST Broad-band Photometry

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Research in astronomy and Astrophysics 2024年第4期24卷 161-173页

作者： Rui-Feng Shi Yang Huang Xin-Yi Li Hua-Wei Zhang School of astronomy and space Science University of Chinese Academy of SciencesBeijing 100049China South-Western Institute for astronomy Research Yunnan UniversityKunming 650500China CAS Key Lab of Optical astronomy Key Laboratory of Space Astronomy and TechnologyNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China College of Physics and Electronic Engineering Qilu Normal UniversityJinan 250200China department of astronomy School of PhysicsPeking UniversityBeijing 100871China Kavli Institute for astronomy and Astrophysics Peking UniversityBeijing 100871China

Deriving atmospheric parameters of a large sample of stars is of vital importance to understand the formation and evolution of the Milky *** surveys,especially those with near-ultraviolet filters,can offer accurate measurements of stellar parameters,with the precision comparable to that from low/medium resolution *** this study,we explore the capability of measuring stellar atmospheric parameters from Chinese space Station Telescope(CSST)broad-band photometry(particularly in the near-ultraviolet bands),based on synthetic colors derived from model *** find that colors from the optical and near-ultraviolet filter systems adopted by CSST show significant sensitivities to the stellar atmospheric parameters,especially the *** to our mock data tests,the precision of the photometric metallicity is quite high,with typical values of0.17 and 0.20 dex for dwarf and giant stars,*** precision of the effective temperature estimated from broad-band colors are within 50 K.

关键词： methods:data analysis stars:abundances surveys

Rapidly growing primordial black holes as seeds of the massive high-redshift JWST Galaxies

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Science China(Physics,Mechanics & astronomy) 2024年第10期67卷 139-146页

作者： Guan-Wen Yuan Lei Lei Yuan-Zhu Wang Bo Wang Yi-Ying Wang Chao Chen Zhao-Qiang Shen Yi-Fu Cai Yi-Zhong Fan 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 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Deep space Exploration Laboratory/department of astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China Jockey Club Institute for Advanced Study The Hong Kong University of Science and TechnologyHong KongChina

A group of massive galaxies at redshifts of z■7 have been recently detected by the James Webb space Telescope(JWST),which were unexpected to form at such an early time within the standard Big Bang *** this work,we propose that this puzzle can be explained by the presence of some primordial black holes(PBHs)with a mass of~1000M_(⊙).These PBHs act as seeds for early galaxy formation with masses of~10^(8)-10^(10)M_(⊙)at high redshift,hence accounting for the JWST *** use a hierarchical Bayesian inference framework to constrain the PBH mass distribution models,and find that the Lognormal model with the M_(c)~750M_(⊙)is preferred over other *** rapidly growing BHs are expected to have strong radiation and may appear as high-redshift compact objects,similar to those recently discovered by *** we focused on PBHs in this work,the bound on the initial mass of the seed black holes remains robust even if they were formed through astrophysical channels.

关键词： primordial black hole dark matter halo black hole accretion primordial galaxies

Finding the magnetopause location using soft X-ray observations and a statistical inverse method

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Earth and Planetary Physics 2024年第1期8卷 184-203页

作者： Gonzalo Cucho-Padin Hyunju Connor Jaewoong Jung Brian Walsh David G.Sibeck space Weather Laboratory NASA Goddard Space Flight CenterGreenbeltMDUSA department of Physics The Catholic University of AmericaWashingtonDCUSA Geospace Physics Laboratory NASA Goddard Space Flight CenterGreenbeltMDUSA astronomy department University of Maryland College ParkCollege ParkMDUSA Center for space Physics Department of Mechanical EngineeringBoston UniversityBostonMAUSA

Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the *** spatial and temporal properties of the magnetopause,under varying solar and magnetospheric conditions,remain largely unknown because empirical studies using in-situ observations are challenging to *** wide field-of-view(FOV)imaging is the only means to simultaneously observe the spatial distribution of the plasma properties over the vast dayside magnetospheric region and,subsequently,quantify the energy transport from the interplanetary medium into the terrestrial *** upcoming missions,ESA/CAS SMILE and NASA’s LEXI will provide wide-field imagery of the dayside magnetosheath in soft X-rays,an emission generated by charge exchange interactions between high charge-state heavy ions of solar wind origin and exospheric neutral ***-cadence two-dimensional observations of the magnetosheath will allow the estimation of dynamic properties of its inner boundary,the magnetopause,and enable studies of its response to changes in the solar wind dynamic pressure and interplanetary magnetic field *** work introduces a statistically-based estimation approach based on inverse theory to estimate the spatial distribution of magnetosheath soft X-ray emissivities and,with this,identify the location of the magnetopause over the Sun−Earth *** do so,we simulate the magnetosheath structure using the MHD-based OpenGGCM model and generate synthetic soft X-ray images using LEXI’s orbit and attitude *** results show that 3-D estimations using the described statistically-based technique are robust against Poisson-distributed shot noise inherent to soft X-ray ***,our proposed methodology shows that the accuracy of both three-dimensional(3-D)estimation and the magnetopause standoff distance calculation hi

关键词： magnetopause soft X-ray tomography

Probing the Galactic Halo with RR Lyrae *** Radial Velocity Curve Templates of RRc Stars

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Research in astronomy and Astrophysics 2024年第7期24卷 118-134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 UniversityYichang 443002China Center for astronomy and space Sciences China Three Gorges UniversityYichang 443002China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of astronomy and space Science University of Science and Technology of ChinaHefei 230026China School of astronomy and space Science University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory of Optical astronomy National Astronomical ObservatoriesBeijing 100101China department of astronomy School of PhysicsPeking UniversityBeijing 100871China Kavli Institute for astronomy and Astrophysics Peking UniversityBeijing 100871China School of Sciences Hangzhou Dianzi UniversityHangzhou 310018China

We present radial velocity(RV)curve templates of RR Lyrae first-overtone(RRc)stars constructed with the Mg I b triplet and Hαlines using time-domain Medium-Resolution Survey spectra of seven RRc stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)Data Release ***,we derive the relation between the stellar RV curve amplitudes and g-band light curve amplitudes from Zwicky Transient Facility(ZTF)public *** 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 *** 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~(-1)and 6.08 km s~(-1)based on the Mg I b triplet and Hαlines,*** calculate the systemic RVs of 30 RRc stars using the RV curve templates constructed with the Mg I b triplet and Hαlines and find the systemic RVs are comparable with each *** RV curve template will be particularly useful for obtaining the systemic RV of RRc using the LAMOST spectroscopy.

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