Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： Quasars are characterized by violent and large amplitude variability in all the observation wavelengths, and the analysis of optical variability is useful for developing theoretical models. Long-term optical variability data of quasar 3C 446 were collected from the University of Michigan Radio Astronomy Observatory database in the 4.8, 8.0 and 14.5\;GHz radio bands from 1976 to 2012. Due to the complexity of the variability data, it's hard to study by the linear time series analysis methods. For learning more about non-linear characteristics of the temporal evolution of quasar variability, the Ensemble Empirical Mode Decomposition and nonlinear analysis are used to analyse chaotic dynamics, fractal properties, and periodicity. This paper focuses on whether there is a significant difference between the periodic and non-linear properties of the quasar variability before and after the removal of the periodic or chaotic components. It turns out that the variability of quasar 3C 446 in the radio bands consists of periodic, trend and chaotic components, and the periodic and trend components are dominant. The periods of the variability after removing the chaotic and trend components are exactly the same as the periods of the original variability data, but the chaotic and fractal characteristics of the two are significantly different. The saturated correlation dimension indicates that the reconstruction of the dynamical system requires more independent parameters than the original optical variables after the removal of the periodic and trend components. The Kolmogorov entropy indicates that the loss of information is greater for the former than the latter, and the system is more chaotic and more complex. The Hurst value indicates that the self-similarity and long-range correlation are slightly stronger for the latter than the former.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The young pulsars mostly locate in the supernova remnants, which can be classified as the rotation-powered pulsars, magnetars and central compact objects, and these three types of young pulsars share the different distributions of the spin periods and magnetic field strengths. % The remnant magnetars share the average spin period larger than the rotation-powered remnant pulsars by nearly one order of magnitude, while their average magnetic field strength is higher than that of the rotation-powered remnant pulsars by about two orders of magnitude. % Meanwhile, the central compact objects share the average magnetic field strength lower than the rotation-powered remnant pulsars by about two orders of magnitude. % The different physical properties of these three types of young pulsars may originate from their different predecessors, or their different supernova processes, and may also originate from their different evolutional processes after the neutron stars were born. % Furthermore, the rotation-powered remnant pulsars exhibit the faster average spin period, the higher average magnetic field strength, and the shorter average characteristic age than the young rotation-powered non-remnant pulsars. % This implies that when the new born neutron star undergos the evolution process with the timescale of $\tau\sim10^5-10^6$\,yr, its spin velocity will decrease by about a half, and its magnetic field strength will also decrease by about a half simultaneously. %
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
WEN Zhi-gang
WANG Na
)
WANG Hong-guang
CHEN Jian-ling
YUAN Jian-ping
YUEN Rai
YAN Wen-ming
TOKTONUR Ergesh
CUI Si-ran
LI Jian
LYU Cheng-bing
Abstract： We study the waiting time distribution of giant pulses from the Crab pulsar observed with the Nanshan 26-m radio telescope at a center frequency of 1556\;MHz with 512 MHz bandwidth. The observations were performed over a duration of 12.6 hours with 32\;$\upmu$s sampling interval. Our analysis has led to the detection of 2097 giant pulses above a threshold of 10 $\sigma$, with flux density $>$ 100\;Jy. The occurrence rate of giant pulses is characterized by a highly intermittent giant pulse productivity in short clusters with high rates, separated by relatively long quiescent intervals with low occurrence rates, especially for the giant pulses associated with the interpulse emission. The distribution of waiting times between two subsequent giant pulses displays a power-law tail and can be modeled with a non-stationary Poisson process, which indicates that giant pulses are independent and random events. Distinct waiting time distributions between giant pulses in the main pulse and interpulse phases are presented, which implies that the giant pulse emission mechanisms maybe different in the opposite magnetic poles. The ramification for our understanding of the radio emission mechanisms is discussed.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The characteristics of Low Surface Brightness Galaxies (LSBGs) are very important for understanding the overall characteristics of galaxies. It is of great significance to search and expand the samples of low surface brightness galaxies by modern machine learning, especially deep learning algorithm. LSBGs are difficult to discern automatically and accurately with traditional methods because of their obscure features. However, deep learning does have the advantage of automatically identifying complex and effective features. To solve this problem, an algorithm named You Only Look Once version X-CS (YOLOX-CS) is proposed to search LSBG in large sample sky survey. Firstly, five classical target detection algorithms are compared through experiments and the optimal YOLOX algorithm is selected as the basic algorithm. Then, the YOLOX-CS framework is constructed by combining different attention mechanisms and different optimizers. The data set uses images from the Sloan Digital Sky Survey (SDSS), labelled from LSBG in the $\alpha$.40-SDSS DR7 (the cross coverage area of 40\% HI Arecibo Legacy Fast ALFA Survey and SDSS Data Release7) survey. Due to the small number of samples in this data set, Deep Convolutional Generative Adversarial Networks (DCGAN) model is used to expand the experimental test data. After comparing with a series of target detection algorithms, YOLOX-CS has a good test result in searching LSBG recall rate and Average Precision (AP) value in two data sets before and after expansion. The recall rate and AP value in the test set without expansion data set reach 97.75\% and 97.83\%, respectively. In the expanded data set of DCGAN model, under the same test set, the recall rate reaches 99.10\% and the AP value reaches 98.94\%, which proves that the algorithm has excellent performance in LSBG search. Finally, the algorithm is applied to SDSS photometric data, and 765 LSBG candidates are obtained.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The morphology of galaxies is closely related to the formation and evolution of galaxies, and its morphological classification is a significant part of the follow-up research of galaxy astronomy. With the emergence of massive astronomical observation data, the automatic analysis of astronomical data has attracted more and more attention. To solve this problem, the advanced deep learning backbone network EfficientNetV2 is utilized to analyze the effects of different attention mechanism types and usage nodes on network performance, and an improved algorithm model named EfficientNetV2-S-Triplet7 is constructed to realize automatic classification of galaxy morphology. More than 240 thousand photometric images from Galaxy Zoo 2 are used as initial data for experimental tests. In the process of data preprocessing, image enhancement methods such as size jittering, flipping and color distortion are adopted to solve the problem of image number imbalance. After conducting comparative experiments on the same series of classic and cutting-edge deep learning algorithms AlexNet, RegNet, MobileNetV2 and ResNet-34, it is concluded that the EfficientNetV2-S-Triplet7 algorithm has the best test results in classification accuracy, recall and F1-score. In 9375 test images, the three index values can reach 89.03\%, 90.21\% and 89.93\%, respectively, and the precision can reach 89.69\%, ranking the third among other models. The results show that EfficientNetV2-S-Triplet7 algorithm can be effectively applied to the morphological classification of large-scale galaxy data.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： With the rapid development of astronomical detection technology, there will be a huge torrent of incoming galaxy images in the coming years, making the automatic galaxy morphology classification a challenging task. To solve the problem of feature selection, the low speed and low accuracy of traditional galaxy morphology classification models, a galaxy morphology classification model based on Inception-v3 neural network with SE (Squeeze and Excitation Network) channel attention mechanism is introduced. We select galaxy images from Sloan Digital Sky Survey (SDSS) for the SE-Inception-v3 model. The test results show that the accuracy of SE-Inception-v3 model is as high as 99.37\%, and the F1 scores of spiral galaxy, completely round smooth galaxy, in-between smooth galaxy, cigar-shaped smooth galaxy and edge-on galaxy are 99.33\%, 99.58\%, 99.33\%, 99.41\% and 99.16\%, respectively. Compared with the MobileNet (Mobile Neural Network) and ResNet (Residual Neural Network) models, the width and depth advantages of SE-Inception-v3 make the classification model have stronger feature extraction capabilities, which provides a new galaxy morphology classification approach for future large-scale sky survey programs.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
KANG Zhe
NIU Bing-li
LI Zhen-wei
SUN Jian-nan
LV You
ZHU Cheng-wei
DENG Shi-yu
LIU De-long
YANG Wen-bo
ZHANG Nan
LIU Ming
SUN Ming-guo
LIU Cheng-zhi
Abstract： Ground-based optical astronomical telescopes are one of the most important instruments for human exploration and research of the universe. Monitoring and analysis of the optical observation environment of the existing ground-based optical station can provide a reference for the targeted modification of equipment and the adjustment of observation strategies of observers, which is of great significance for improving the observation efficiency of ground-based optical equipment. Jilin Astronomical Observatory (hereinafter referred to as the ``Base'') is located about 5 kilometers (126.3$^{\circ}$ E, 43.8$^{\circ}$ N, 313 meters above sea level) in Nangou, Xiaosuihe Village, Dasuihe Town, Jilin City, Jilin Province, which is affiliated to the Changchun Observatory, National Astronomical Observatories, Chinese Academy of Sciences. The mean value of seeing of the base is about 1.3$''$--1.4$''$, the night sky brightness in the V band near the zenith is 20.64\;mag\,$\cdot$\,arcsec$^{-2}$, and the maximum number of clear nights is better than 270 days per year, which shows the good astronomical observation conditions. Jilin Astronomical Observatory, which was put into operation in 2016, has several photoelectric telescopes, including the 1.2-meter photoelectric telescope, the Mini Optoelectronic Telescope Array, the large field of view photoelectric telescope array, and the advanced multi-functional array-structured photoelectric detector. With the equipments mentioned above, we have carried out relevant research mainly on space target detection and recognition, precision orbit determination, new photoelectric detection methods and multicolor photometry of variables, and so forth. We have maintained a good cooperative relationship with a number of domestic universities and scientific research institutes.
Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： High energy particles near the particle acceleration region in young supernova remnants and pulsar wind nebulae can emit X-ray synchrotron radiation. The polarization measurement of this radiation can reveal the properties of the magnetic field in the particle acceleration region, and further study the mechanism of particle acceleration. As the first X-ray polarization imaging satellite, the Imaging X-ray Polarization Detector (IXPE) was launched in late 2021 and revealed the X-ray polarization images of several young supernova remnants and pulsar wind nebulae. Observations show that Cas A and Tycho’s supernova remnant have low polarization degrees with average values of about 2.5% and 9%, respec#2;tively, while the Crab Nebula and Vela pulsar wind nebula have higher polarization degrees, averaging about 20% and 45%, respectively. The results indicate that the magnetic field of the pulsar wind nebulae is relatively ordered, while the magnetic field of the particle accel#2;eration region in the two young supernova remnants is highly turbulent and the magnetic field structure near the shock wave shows a radial distribution. In the future, with more extensive observations of IXPE and more telescopes such as the enhanced X-ray Timing and Polarimetry (eXTP) mission planned by China in use, the magnetic field configuration and particle acceleration models of the above two types of objects will be further constrained.
Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： The bar structure of disk galaxies, their environment, and overall star formation properties are known to be intricately linked. By utilizing data from the Galaxy Zoo DECaLS program, we have assembled the largest sample of strong bar, weak bar, and no bar galaxies with matching stellar mass distributions. We analyzed the specific star formation rates (sSFR) of these galaxies after controlling for environmental effects by matching the halo mass and phase space diagram of the dark matter halo in which the galaxy resides. Our findings suggest that the percentage of quenched galaxies in the barred galaxy sample is consistently higher than that in non-bar galaxies, with a more pronounced effect for strong bar galaxies. However, for galaxies that are still on the star formation main sequence, there is no significant difference in their sSFR distribution. These results suggest that the presence of a bar in a galaxy may rapidly transition some galaxies from being star-forming to quenched in a short period of time.
Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： White dwarfs are the degenerate stellar cores remaining at the end of the evo#2;lution of low- and median-mass stars, which represent the final fate of more than 97% of the celestial bodies in the Milky Way. White dwarfs contain the information of stars from birth to death, which can be used to constrain the theory of stellar evolution, such as the mass loss rate in the post-AGB stage at the end of stellar evolution, which also directly affects the initial-final mass relation of stars. White dwarfs may arise from the evolution of multiple star systems. It is estimated that 25% ∼ 30% of white dwarfs are the outcome of binary or multiple star mergers, and white dwarfs with a mass less than 0.4 M⊙ are generally considered to be the result of binary evolution. Therefore, white dwarfs can be used to verify the binary star evolution theory. The white dwarf cooling sequence provides an independent cosmic clock to constrain the ages of the various stellar populations in the Milky Way. Since the white dwarf population contain information about the formation his#2;tory and evolution of the Milky Way, and the study of the properties of the white dwarf population requires a large number of well-defined white dwarf samples. Combining Gaia’s high-precision photometry and annual parallax data, we searched for white dwarfs in the low-resolution spectroscopic data of the eighth data release (DR8) of LAMOST. By using the method of template matching, a total of 4 692 white dwarfs and 85 cataclysmic variables were found in LAMOST DR8, among which 2 876 objects were proved to be white dwarfs in the previous work, and 1 854 objects were white dwarfs discovered in LAMOST for the first time. After visual confirmation, we carried out a detailed classification of the white dwarf spectral types. After comparison, the completeness of the white dwarf sample is 80%, and the accuracy of classification is 99%. The final LAMOST white dwarf sample can well reflect the distribution of different types of white dwarfs on the Gaia CMD map.
Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： Time series reconstruction is a crucial data processing step in time domain astronomy and serves as the foundation for fitting light curves and conducting time domain analysis. For many large-field time domain surveys, it is necessary to complete this computational process within a single exposure cycle. With the rapid increase in astronomical data, existing methods for astronomical data processing struggle to simultaneously meet the accuracy and efficiency requirements of time-series reconstruction. The memory-based computing general-purpose distributed framework, Spark, holds the potential to improve the efficiency of this process. However, applying Spark directly often encounters issues. MapReduce distributed models like Hadoop and Spark require relatively independent tasks among distributed cluster nodes and minimal data transfer across nodes during execution. Otherwise, frequent communication becomes an efficiency bottleneck for the application of the model. However, due to the presence of boundary problems in cross-matching, it is inevitable to transmit newly added data at the boundaries, severely restricting the concurrency of the model and reducing the acceleration ratio in practical parallel model applications. Therefore, we propose a non-blocking asynchronous execution flow, where each distributed process handles continuous processing exclusively for independent sky regions. The delayed batch appending of additional identification tasks from block-edge newly added celestial bodies in other nodes is determined based on the progress of each process. This ensures that identification calculations are not omitted, thereby improving concurrent efficiency while maintaining algorithm accuracy. Additionally, a research study was conducted on different join strategies between two tables, examining them from both theoretical and experimental perspectives. Furthermore, a join-free strategy was proposed. Finally, the design of an efficient time-series reconstruction system based on the Spark distributed framework validates the aforementioned research. Experimental results demonstrate a significant improvement in the efficiency of the proposed time-series reconstruction algorithm compared to previous research, laying a solid foundation for the analysis of astronomical time-series data in time-domain astronomy.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： Pulsars have significant academic and application value in fields such as astrophysical evolution, physics, timing, deep space autonomous navigation, and gravitational wave detection, making pulsar survey and application one of the current hot topics in the astronomical community. In order to explore the current research status and future development trends in the field of pulsar survey and application, 964 relevant articles were screened from the Web of Science (WOS) database. Building upon the analysis of core articles, in-depth exploration was conducted utilizing data analysis and visualization methods. The study results reveal that research in the field of pulsar survey and application has progressed through initial exploration and steady development phases, and is currently experiencing vigorous growth. Close collaboration among nations has led to the formation of three major research groups in this field. Pulsar survey and application research are anticipated to yield significant scientific research value and practical application outcomes in the future, such as direct detection of gravitational waves and advancements in deep space autonomous navigation, thereby further enriching and diversifying the research domain of pulsars.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： We describe the application and funding situation of NSFC regular programs in the astronomy discipline in 2023, and analyze the distribution and change of the application and funding in terms of field and age, and point out the problems found in the application and review of the fund programs in the year 2023, and put forward considerations for the future funding of the astronomy discipline.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： Temperature is one of the key factors influencing the performance of large-scale radio telescopes. Taking the Tianma Radio Telescope (TMRT) as an example, this study investigates the relationship between the temperature of the alidade’s nodes and antenna pointing accuracy. A method is proposed for constructing a correction model for pointing errors based on node temperatures. The pointing error is treated as a linear combination of the alidade’s node temperatures. The number of independent variables is optimized using the temperature sensitivity of the nodes as feature conditions. The pointing test results of the source 2344+8226 near the North Pole are used as the sample set to compare the effec#2;tiveness of the temperature model before and after variable simplification. Both the model calculations and finite element analysis validate the two temperature models, which align with the sample set. Furthermore, to assess model generalization, the performance of the models is compared across four seasons before and after simplification. The results indicate that the simplified temperature model offers improved predictive accuracy. The established node temperature-based pointing error correction model’s rapid calculation outcomes pro#2;vide data for real-time mitigation of thermally induced pointing errors in the moun
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： In this paper, a single panel deformation of the main reflector of a large radio telescope is studied and the six degrees of freedom attitude change of robotics is applied to the deformation of the reflector panel of a large radio telescope. A characterization method of panel deformation based on six degrees of freedom deformation of rigid body is proposed. Based on the six-DOF attitude deformation theory of rigid body, an optical reconstruction technique of antenna panel deformation is proposed in this paper. This technology can reconstruct the deformation of the panel quickly and accurately by the spot image presented by the laser unit consolidated on the panel. In this paper, the mapping relationship between laser spot and antenna panel deformation is deeply explored, and the spatial deformation problem of antenna panel is transformed into the laser spot displacement problem in a finite region. And the light spot image of this scheme is studied, and an effective light spot image processing algorithm is provided. It integrates the image difference method and Canny edge detection algorithm, which can effectively solve the problem of traditional Canny algorithm in dealing with small targets. It also uses the high-precision sub-pixel centroid localization algorithm, which can locate light spots at sub-pixel level. It provides a new and reliable image processing method for antenna panel measurement. This study also provides a new idea and method for improving the accuracy and efficiency of antenna panel measurement.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： Electromagnetic waves will be absorbed when they pass through the atmo#2;sphere. Electromagnetic waves with some frequencies are absorbed more, while electromag#2;netic waves with other frequencies are absorbed less. The frequency range within which the electromagnetic waves are less absorbed is called the atmospheric window of electro#2;magnetic waves. Similarly, the propagation of electromagnetic waves in the universe will be absorbed by the galactic medium. This paper investigates the problem of the absorption of electromagnetic wave when it propagates in the Milky Way. Our analysis shows that there is a lower cut-off frequency for the electromagnetic waves which can reach the earth passing through the Milky Way. Interestingly, the lower cut-off frequency is different respect to different direction on the celestial sphere, which gives a distribution. This distribution is closely related to the distribution of free electron gas in the Milky Way. We propose to determine the distribution of free electron gas in the Milky Way by measuring the cut-off frequency distribution.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： High energy particles near the particle acceleration region in young supernova remnants and pulsar wind nebulae can emit X-ray synchrotron radiation. The polarization measurement of this radiation can reveal the properties of the magnetic field in the particle acceleration region, and further study the mechanism of particle acceleration. As the first X-ray polarization imaging satellite, the Imaging X-ray Polarization Detector (IXPE) was launched in late 2021 and revealed the X-ray polarization images of several young supernova remnants and pulsar wind nebulae. Observations show that Cas A and Tycho’s supernova remnant have low polarization degrees with average values of about 2.5% and 9%, respec#2;tively, while the Crab Nebula and Vela pulsar wind nebula have higher polarization degrees, averaging about 20% and 45%, respectively. The results indicate that the magnetic field of the pulsar wind nebulae is relatively ordered, while the magnetic field of the particle accel#2;eration region in the two young supernova remnants is highly turbulent and the magnetic field structure near the shock wave shows a radial distribution. In the future, with more extensive observations of IXPE and more telescopes such as the enhanced X-ray Timing and Polarimetry (eXTP) mission planned by China in use, the magnetic field configuration and particle acceleration models of the above two types of objects will be further constrained.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： The bar structure of disk galaxies, their environment, and overall star formation properties are known to be intricately linked. By utilizing data from the Galaxy Zoo DECaLS program, we have assembled the largest sample of strong bar, weak bar, and no bar galaxies with matching stellar mass distributions. We analyzed the specific star formation rates (sSFR) of these galaxies after controlling for environmental effects by matching the halo mass and phase space diagram of the dark matter halo in which the galaxy resides. Our findings suggest that the percentage of quenched galaxies in the barred galaxy sample is consistently higher than that in non-bar galaxies, with a more pronounced effect for strong bar galaxies. However, for galaxies that are still on the star formation main sequence, there is no significant difference in their sSFR distribution. These results suggest that the presence of a bar in a galaxy may rapidly transition some galaxies from being star-forming to quenched in a short period of time.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： White dwarfs are the degenerate stellar cores remaining at the end of the evo#2;lution of low- and median-mass stars, which represent the final fate of more than 97% of the celestial bodies in the Milky Way. White dwarfs contain the information of stars from birth to death, which can be used to constrain the theory of stellar evolution, such as the mass loss rate in the post-AGB stage at the end of stellar evolution, which also directly affects the initial-final mass relation of stars. White dwarfs may arise from the evolution of multiple star systems. It is estimated that 25% ∼ 30% of white dwarfs are the outcome of binary or multiple star mergers, and white dwarfs with a mass less than 0.4 M⊙ are generally considered to be the result of binary evolution. Therefore, white dwarfs can be used to verify the binary star evolution theory. The white dwarf cooling sequence provides an independent cosmic clock to constrain the ages of the various stellar populations in the Milky Way. Since the white dwarf population contain information about the formation his#2;tory and evolution of the Milky Way, and the study of the properties of the white dwarf population requires a large number of well-defined white dwarf samples. Combining Gaia’s high-precision photometry and annual parallax data, we searched for white dwarfs in the low-resolution spectroscopic data of the eighth data release (DR8) of LAMOST. By using the method of template matching, a total of 4 692 white dwarfs and 85 cataclysmic variables were found in LAMOST DR8, among which 2 876 objects were proved to be white dwarfs in the previous work, and 1 854 objects were white dwarfs discovered in LAMOST for the first time. After visual confirmation, we carried out a detailed classification of the white dwarf spectral types. After comparison, the completeness of the white dwarf sample is 80%, and the accuracy of classification is 99%. The final LAMOST white dwarf sample can well reflect the distribution of different types of white dwarfs on the Gaia CMD map.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： Time series reconstruction is a crucial data processing step in time domain astronomy and serves as the foundation for fitting light curves and conducting time domain analysis. For many large-field time domain surveys, it is necessary to complete this computational process within a single exposure cycle. With the rapid increase in astronomical data, existing methods for astronomical data processing struggle to simultaneously meet the accuracy and efficiency requirements of time-series reconstruction. The memory-based computing general-purpose distributed framework, Spark, holds the potential to improve the efficiency of this process. However, applying Spark directly often encounters issues. MapReduce distributed models like Hadoop and Spark require relatively independent tasks among distributed cluster nodes and minimal data transfer across nodes during execution. Otherwise, frequent communication becomes an efficiency bottleneck for the application of the model. However, due to the presence of boundary problems in cross-matching, it is inevitable to transmit newly added data at the boundaries, severely restricting the concurrency of the model and reducing the acceleration ratio in practical parallel model applications. Therefore, we propose a non-blocking asynchronous execution flow, where each distributed process handles continuous processing exclusively for independent sky regions. The delayed batch appending of additional identification tasks from block-edge newly added celestial bodies in other nodes is determined based on the progress of each process. This ensures that identification calculations are not omitted, thereby improving concurrent efficiency while maintaining algorithm accuracy. Additionally, a research study was conducted on different join strategies between two tables, examining them from both theoretical and experimental perspectives. Furthermore, a join-free strategy was proposed. Finally, the design of an efficient time-series reconstruction system based on the Spark distributed framework validates the aforementioned research. Experimental results demonstrate a significant improvement in the efficiency of the proposed time-series reconstruction algorithm compared to previous research, laying a solid foundation for the analysis of astronomical time-series data in time-domain astronomy.
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