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天文和天体物理学研究
天文和天体物理学研究

汪景琇 景益鹏

月刊

1674-4527

wenyy@bao.ac.cn

010-64853746

100717

北京朝阳区大屯路甲20号国家天文台 RAA编辑部

天文和天体物理学研究/Journal Research in Astronomy and AstrophysicsCSCD北大核心CSTPCDSCI
查看更多>>本刊1981年创刊至2000年已出版20卷。创刊时为中文期刊,2001年改为《中国天文和天体物理学报》(英文版)。主要刊登天文学和天体物理学领域的原创性研究论文。主要栏目和报道范围:“研究快报”用来报道天文观测的新结果及新理论;“特约综述”聘请国际知名天文学家就某些热点问题进行专题评述。“研究论文”具有原创性。2009年更名为《天文和天体物理学研究》(英文版),由双月刊变为月刊。
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    Components and Anisotropy of 3D QFP Waves During the Early Solar Eruption

    Jialiang HuJing YeYuhao ChenZhixing Mei...
    105-115页
    查看更多>>摘要:The propagation of disturbances in the solar atmosphere is inherently three-dimensional(3D),yet comprehensive studies on the spatial structure and dynamics of 3D wave fronts are scarce.Here we conduct high-resolution 3D numerical simulations to investigate filament eruptions,focusing particularly on the 3D structure and genesis of extreme ultraviolet(EUV)waves.Our results demonstrate that the EUV wave front forms a dome-like configuration subdivided into three distinct zones.The foremost zone,preceding the flux rope,consists of fast-mode shock waves that heat the adjacent plasma.Adjacent to either side of the flux rope,the second zone contains expansion waves that cool the nearby plasma.The third zone,at the juncture of the first two,exhibits minimal disturbances.This anisotropic structure of the wave front stems from the configuration and dynamics of the flux rope,which acts as a 3D piston during eruptions—compressing the plasma ahead to generate fast-mode shocks and evacuating the plasma behind to induce expansion waves.This dynamic results in the observed anisotropic wave front.Additionally,with synthetic EUV images from simulation data,the EUV waves are observable in Atmospheric Imaging Assembly 193 and 211 Å,which are identified as the fast-mode shocks.The detection of EUV waves varies with the observational perspective:the face-on view reveals EUV waves from the lower to the higher corona,whereas an edge-on view uncovers these waves only in the higher corona.

    JWST Observations Constrain the Time Evolution of Fine Structure Constants and Dark Energy-electromagnetic Coupling

    Ze-Fan WangLei LeiLei FengYi-Zhong Fan...
    116-124页
    查看更多>>摘要:It was hypothesized in the literature that some physical parameters may be time-evolving and the astrophysical data can serve as a probe.Recently,the James Webb Space Telescope(JWST)released its early observations.In this work,we select the JWST spectroscopic observations of the high redshift(z>7.1)galaxies with strong[O nI](λ=4959 Å and 5007 Å in the rest frame)emission lines to constraint the evolution of the fine structure constant(α).With the spectra from two galaxies at redshifts of 7.19 and 8.47,the deviation of α from its fiducial value is found to be as small as 0.44+8.4+1.7-8.3-1.7 ×10-4 and-10.0+18+1.5-18-1.5 × 10-4,respectively(the first error is statistical and the latter is systematic).The combination of our results with the previous data reveals that 1/αdα/dt=0.30+4.5-4.5× 10-17 yr-1.Clearly,there is no evidence for a cosmic evolution of α.The prospect of further constraining the time evolution of α is also discussed.The scalar field of dark energy is hypothesized to drive the acceleration of the universe's expansion through an interaction with the electromagnetic field.By integrating the observational data of the fine-structure constant variation,Δα/α(z),we have established a stringent upper limit on the coupling strength between dark energy and electromagnetism.Our analysis yields ζ ≤ 3.92 × 10-7 at the 95%confidence level,representing the most stringent bound to date.

    BSN:The First Photometric Analysis of Contact Binary Systems V1961 Cyg and V0890 Lyr

    Sabrina BaudartAtila Poro
    125-137页
    查看更多>>摘要:We presented the first photometric analysis of the V1961 Cyg and V0890 Lyr binary systems.We observed and analyzed these systems at an observatory in France as part of the Binary Systems of South and North(BSN)Project.We extracted and collected the times of minima from the observations and literature and presented a new ephemeris for each system.Due to the few observations about these systems over the years,both O-C diagrams were fitted linearly.The PHysics Of Eclipsing BinariEs(PHOEBE)Python code and the Markov Chain Monte Carlo(MCMC)method were used for light curve solutions.The light curve solution required a cold starspot on the hotter component in the V1961 Cyg binary system.We compared and have close agreements between our mass ratios'results from the light curve analysis processes and a new method based on the light curve derivative.We estimated the absolute parameters using an empirical relationship between the semimajor axis and orbital period for contact binary systems.The results show V1961 Cyg and V0890 Lyr are W-type contact binary systems.We displayed stars and systems'positions in the M-L,M-R,and logMtot-logJ0 diagrams.We also presented a new relationship between mass ratio and luminosity ratio.

    Spectroscopic Study of Late-type Emission-line Stars Using the Data from LAMOST DR6

    D.EdwinBlesson MathewB.ShridharanVineeth Valsan...
    138-155页
    查看更多>>摘要:Low-mass emission-line stars belong to various evolutionary stages,from pre-main-sequence young stars to evolved stars.In this work,we present a catalog of late-type(F0 to M9)emission-line stars from the LAMOST Data Release 6.Using the scipy package,we created a Python code that finds the emission peak at Hα in all late-type stellar spectra.A data set of 38,152 late-type emission-line stars was obtained after a rigorous examination of the photometric quality flags and the signal-to-noise ratio of the spectra.Adopting well-known photometric and spectroscopic methods,we classified our sample into 438 infrared(IR)excess sources,4669 post-main-sequence candidates,9718 Fe/Ge/Ke sources,and 23,264 dMe sources.From a crossmatch with known databases,we found that 29,222 sources,comprising 65 IR excess sources,7899 Fe/Ge/Ke stars,17,533 dMe stars,and 3725 PtMS candidates,are new detections.We measured the equivalent width of the major emission lines observed in the spectra of our sample of emission-line stars.Furthermore,the trend observed in the line strengths of major emission lines over the entire late-type spectral range is analyzed.We further classified the sample into four groups based on the presence of hydrogen and calcium emission lines.This work presents a large data set of late-type emission-line stars,which can be used to study active phenomena in late-type stars.

    Modeling the Covariance Matrix for the Power Spectra Before and After the BAO Reconstruction

    Ruiyang ZhaoKazuya KoyamaYuting WangGong-Bo Zhao...
    156-174页
    查看更多>>摘要:The baryon acoustic oscillations(BAO)reconstruction plays a crucial role in cosmological analysis for spectroscopic galaxy surveys because it can make the density field effectively more linear and more Gaussian.The combination of the power spectra before and after the BAO reconstruction helps break degeneracies among parameters,then improves the constraints on cosmological parameters.It is therefore important to estimate the covariance matrix between pre-and post-reconstructed power spectra.In this work,we use perturbation theory to estimate the covariance matrix of the related power spectra multipoles,and check the accuracy of the derived covariance model using a large suite of dark matter halo catalogs at z=0.5.We find that the diagonal part of the auto covariance is well described by the Gaussian prediction,while the cross covariance deviates from the Gaussian prediction quickly when k>0.1 h Mpc-1.Additionally,we find the non-Gaussian effect in the non-diagonal part of the cross covariance is comparable to,or even stronger than,the pre-reconstruction covariance.By adding the non-Gaussian contribution,we obtain good agreement between analytical and numerical covariance matrices in the non-diagonal part up to k~0.15 h Mpc-1.The agreement in the diagonal part is also improved,but still under-predicts the correlation in the cross covariance block.

    Constrain the Jerk Parameters with DESI 2024 Data

    Jia-Wei WuKun-Yuan Hong
    175-182页
    查看更多>>摘要:The deceleration coefficient q and the jerk coefficient j obtained by the Taylor expansion of the scale factor a(t)play an important role in the study of cosmology.The current value of these coefficients for a cosmological model reflects the transition time between the phases dominated by dark energy and matter and can be used to determine if and how much the universe is decelerating.Thus,these coefficient values offer a way of constraining a particular cosmology model.Research based on this scenario was completed by Orlando Luongo and Marco Muccino.However,some approaches in this method should be tested prudently because some conditions such as ddL/dz>0 and dH/dx>0 may not be guaranteed.In this study,we used the MAPAge model to reconstruct the jerk parameters(q0 and j0)with DESI 2024 data.Using the MAPAge model ensures particular physical circumstances are satisfied in the approach of determining the jerk parameters.Compared to the previous method,which used the Taylor expansion series q0,j0,and s0 as model-independent parameters,we obtained more physical and slightly different results for the jerk parameters.Our results suggest that the DESI 2024 BAO data set favours different jerk parameters compared to the jerk parameters in the standard ACDM model.

    A Special Kind of Interplanetary Coronal Mass Ejection

    H.Q.FengY.ZhaoG.Q.ZhaoH.B.Li...
    183-191页
    查看更多>>摘要:It is generally believed that coronal mass ejections(CMEs)have magnetic flux rope structures because of their helical shapes.However,only about 30%-40%of interplanetary CMEs(ICMEs)have a local magnetic flux rope structure.The usual explanations are that the spacecraft only crossed the flank of the ropes and failed to detect the complete magnetic flux rope structure or that some processes destroyed these magnetic flux rope structures.Several studies suggest that some ICMEs inherently possess disordered magnetic fields and consequently exhibit no magnetic flux-rope structures.We introduce a special kind of ICME which has a low magnetic field magnitude and stable magnetic field direction,relatively fast expansion speed,and lower proton temperature and density.All three of the measured magnetic field components are relatively stable.We want to know whether these ICMEs also have magnetic flux rope structures or not.We identified 20 special ICMEs and analyzed their evolution based on their observed characteristics.We took a special ICME as an example,which had an apparent rope configuration at 1 au but evolved to a special ICME at 5.4 au,to illustrate that this kind of ICME could come from magnetic clouds(MCs)whose rope structure had been being stretched due to expansion.We inferred that the missing obvious flux rope structure may be due to the expansion of MCs,not the flank crossing effect.However,more than 50%of the events were associated with the dominant x-component of the magnetic field,which indicates a leg crossing.Therefore,the detection of part of these special ICMEs may also be the result of the leg-crossing effect.

    Simulating the Peculiar Periphery of the Cygnus Loop

    Jun-Yu ShenBi-Wen BaoLi Zhang
    192-206页
    查看更多>>摘要:The middle-aged Galactic supernova remnant(SNR)-the Cygnus Loop(CL)-displays a peculiar morphology in X-rays,featuring a blowout in the southern region.The underlying process accounting for the formation of the peculiar periphery remains a mystery.To this end,we conduct hydrodynamical simulations to investigate the SNR evolution coupled with a tailored stellar-wind model:a bipolar stellar wind emanating from a runaway red supergiant progenitor,excavating a wind-blown cavity elongated along the-z-direction.Our simulation results reveal that the forward shock of the consequent SNR sweeps up the modified ambient media,shaping the overall morphology with a blowout comparable to that of CL.Besides,a series of simulation runs are performed to assess the impacts of different model parameters and the projection effect(observational angle θobs)on the final SNR profile.Three physical quantities are extracted from simulation results to characterize the simulated SNR and make a direct comparison with the X-ray observations of CL.We find that the final SNR morphology is sensitive to both stellar-wind properties and θobs.A Cygnus-Loop-like SNR could be reproduced under appropriate parameter combinations at θobs=0°.While for θobs<30°,the projected morphology akin to CL could be also generated under specific conditions.

    Multi-layer Perceptron for Predicting Galaxy Parameters(MLP-GaP):Stellar Masses and Star Formation Rates

    郭晓通Guanwen FangHaicheng FengRui Zhang...
    207-218页
    查看更多>>摘要:The large-scale imaging survey will produce massive photometric data in multi-bands for billions of galaxies.Defining strategies to quickly and efficiently extract useful physical information from this data is mandatory.Among the stellar population parameters for galaxies,their stellar masses and star formation rates(SFRs)are the most fundamental.We develop a novel tool,Multi-Layer Perceptron for Predicting Galaxy Parameters(MLP-GaP),that uses a machine learning(ML)algorithm to accurately and efficiently derive the stellar masses and SFRs from multi-band catalogs.We first adopt a mock data set generated by the Code Investigating GALaxy Emission(CIGALE)for training and testing data sets.Subsequently,we used a multi-layer perceptron model to build MLP-GaP and effectively trained it with the training data set.The results of the test performed on the mock data set show that MLP-GaP can accurately predict the reference values.Besides MLP-GaP has a significantly faster processing speed than CIGALE.To demonstrate the science-readiness of the MLP-GaP,we also apply it to a real data sample and compare the stellar masses and SFRs with CIGALE.Overall,the predicted values of MLP-GaP show a very good consistency with the estimated values derived from spectral energy distribution fitting.Therefore,the capability of MLP-GaP to rapidly and accurately predict stellar masses and SFRs makes it particularly well-suited for analyzing huge amounts of galaxies in the era of large sky surveys.

    A Real-time Monitor for TeV Gamma-Ray Flare with the LHAASO-WCDA Detector

    G.M.XiangM.ZhaJ.N.ZhouY.Xing...
    219-228页
    查看更多>>摘要:With its high duty cycle,wide field of view and high detection sensitivity,Water Chereknov Detector Array as one of sub-arrays of Large High Altitude Air Shower Observatory is a promising facility to monitor transient phenomena in the very high energy gamma-ray band.In this work,a real-time monitor for selected TeV extragalactic sources is introduced,this flare monitor is developed to detect very high energy flare events and for further studying the power-providing mechanism of blazar relativistic jets.The detailed information such as the searching method and sensitivity of this real-time flare monitor is also presented.In the end,successful multi-wavelength and multi-messenger observation of 1ES 1959+650 and IC 310 also confirms the capabilities and reliability of the monitoring system.