Research in Astronomy and Astrophysics最新文献

{"title":"Polarization Study of Swift J151857.0–572147 with IXPE Observation","authors":"Yu-Shan Ling, Fei Xie, Ming-Yu Ge and Fabio La Monaca","doi":"10.1088/1674-4527/ad6edf","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6edf","url":null,"abstract":"We present an analysis of the Imaging X-ray Polarimetry Explorer observation from a newly discovered transient source: Swift J151857.0–572147. The obtained polarization degree (PD) and angle are 0.3% ± 0.3% and −24° ± 26° respectively in 2–8 keV within 68% confidence level errors, and polarization results are below MDP99 in all energy bins, with the upper limit on PD of 0.8% in the 2–8 keV energy range. No quasi-periodic oscillations (QPOs) are detected in this observation. The polarization and QPO analyses support the hypothesis that the source was in the high soft state, and the results are consistent with predictions for a thin accretion disk model.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"24 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining the Earth-mass Primordial Black Hole Mergers Model of the Non-repeating FRBs Using the First CHIME/FRB Catalog","authors":"Min Meng, Qiu-Ju Huang, Can-Min Deng","doi":"10.1088/1674-4527/ad6fe7","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6fe7","url":null,"abstract":"In this paper, we upgrade the constraints for the Earth-mass primordial black hole mergers model based on the first Canadian Hydrogen Intensity Mapping Experiment (CHIME)/fast radio burst (FRB) catalog. Assuming the null hypothesis that the observed non-repeating FRBs originate from Earth-mass primordial black hole mergers, we find that how the charges were distributed in the primordial black hole population is well described by a double power-law function with typical charge value of <inline-formula>\u0000<tex-math>\u0000<?CDATA ${q}_{{rm{c}}}/{10}^{-5}={1.60}_{-0.28}^{+0.28}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi>q</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant=\"normal\">c</mml:mi></mml:mrow></mml:msub><mml:mrow><mml:mo stretchy=\"true\">/</mml:mo></mml:mrow><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:msubsup><mml:mrow><mml:mn>1.60</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.28</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.28</mml:mn></mml:mrow></mml:msubsup></mml:math>\u0000<inline-graphic xlink:href=\"raaad6fe7ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>, where the power-law index <inline-formula>\u0000<tex-math>\u0000<?CDATA ${alpha }_{1}={2.33}_{-0.18}^{+0.15}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi>α</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:msubsup><mml:mrow><mml:mn>2.33</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.18</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.15</mml:mn></mml:mrow></mml:msubsup></mml:math>\u0000<inline-graphic xlink:href=\"raaad6fe7ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> for <italic toggle=\"yes\">q</italic> < <italic toggle=\"yes\">q</italic>\u0000<sub>c</sub> and <inline-formula>\u0000<tex-math>\u0000<?CDATA ${alpha }_{2}={4.56}_{-0.26}^{+0.30}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi>α</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:msubsup><mml:mrow><mml:mn>4.56</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.26</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.30</mml:mn></mml:mrow></mml:msubsup></mml:math>\u0000<inline-graphic xlink:href=\"raaad6fe7ieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> for <italic toggle=\"yes\">q</italic> ≥ <italic toggle=\"yes\">q</italic>\u0000<sub>c</sub>. Here, <italic toggle=\"yes\">q</italic> represents the charge of the black hole in units of <inline-formula>\u0000<tex-math>\u0000<?CDATA $sqrt{G}M$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msqrt><mml:mrow><mml:mi>G</mml:mi></mml:mrow></mml:msqrt><mml:mi>M</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"raaad6fe7ieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>, where <italic toggle=\"yes\">M</italic> is the mass of the black hole. Furthermore, we infer the local event rate of","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"2021 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The GECAM Real-time Burst Alert System","authors":"Yue Huang, Dongli Shi, Xiaolu Zhang, Xiang Ma, Peng Zhang, Shijie Zheng, Liming Song, Xiaoyun Zhao, Wei Chen, Rui Qiao, Xinying Song, Jin Wang, Ce Cai, Shuo Xiao, Yanqiu Zhang, Shaolin Xiong","doi":"10.1088/1674-4527/ad6839","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6839","url":null,"abstract":"Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM), consisting of two micro-satellites, is designed to detect gamma-ray bursts associated with gravitational-wave events. Here, we introduce the real-time burst alert system of GECAM, with the adoption of the BeiDou-3 short message communication service. We present the post-trigger operations, the detailed ground-based analysis, and the performance of the system. In the first year of the in-flight operation, GECAM was triggered by 42 gamma-ray bursts. The GECAM real-time burst alert system has the ability to distribute the alert within ∼1 minute after being triggered, which enables timely follow-up observations.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"20 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Localization Method of High Energy Transients for All-sky Gamma-ray Monitor","authors":"Yi Zhao, Wangchen Xue, Shaolin Xiong, Qi Luo, Yuanhao Wang, Jiacong Liu, Heng Yu, Xiaoyun Zhao, Yue Huang, Jinyuan Liao, Jianchao Sun, Xiaobo Li, Qibin Yi, Ce Cai, Shuo Xiao, Shenglun Xie, Chao Zheng, Yanqiu Zhang, Chenwei Wang, Wenjun Tan, Zhiwei Guo, Chaoyang Li, Zhenghua An, Gang Chen, Yanqi Du, Min Gao, Ke Gong, Dongya Guo, Jiang He, Jianjian He, Bing Li, Gang Li, Xinqiao Li, Jing Liang, Xiaohua Liang, Yaqing Liu, Xiang Ma, Rui Qiao, Liming Song, Xinying Song, Xilei Sun, Jin Wang, Ping Wang, Xiangyang Wen, Hong Wu, Yanbing Xu, Sheng Yang, Dali Zhang, Fan Zhang, Hongmei Zhang, Peng Zhang, Shu Zhang, Zhen Zhang, Shijie Zheng, Keke Zhang, Xingbo Han, Haiyan Wu, Hu Tai, Hao Geng, Gaopeng Lu, Wei Xu, Fanchao Lyu, Hongbo Zhang, Fangjun Lu, Shuangnan Zhang","doi":"10.1088/1674-4527/ad683b","DOIUrl":"https://doi.org/10.1088/1674-4527/ad683b","url":null,"abstract":"Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations. Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors. There are two major methods for this count distribution localization: <italic toggle=\"yes\">χ</italic>\u0000² minimization method and the Bayesian method. Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the <italic toggle=\"yes\">χ</italic>\u0000² method. With comprehensive simulations, we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the <italic toggle=\"yes\">χ</italic>\u0000² method, especially for weak bursts. We further proposed a location-spectrum iteration approach based on the Bayesian inference, which could alleviate the problems caused by the spectral difference between the burst and location templates. Our method is very suitable for scenarios with limited computation resources or time-sensitive applications, such as in-flight localization software, and low-latency localization for rapidly follow-up observations.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"162 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The In-Flight Realtime Trigger and Localization Software of GECAM","authors":"Xiao-Yun Zhao, Shao-Lin Xiong, Xiang-Yang Wen, Xin-Qiao Li, Ce Cai, Shuo Xiao, Qi Luo, Wen-Xi Peng, Dong-Ya Guo, Zheng-Hua An, Ke Gong, Jin-Yuan Liao, Yan-Qiu Zhang, Yue Huang, Lu Li, Xing Wen, Fei Zhang, Jing Duan, Chen-Wei Wang, Dong-Li Shi, Peng Zhang, Qi-Bin Yi, Chao-Yang Li, Yan-Bing Xu, Xiao-Hua Liang, Ya-Qing Liu, Da-Li Zhang, Xi-Lei Sun, Fan Zhang, Gang Chen, Huan-Yu Wang, Sheng Yang, Xiao-Jing Liu, Min Gao, Mao-Shun Li, Jin-Zhou Wang, Xing Zhou, Yi Zhao, Wang-Chen Xue, Chao Zheng, Jia-Cong Liu, Xing-Bo Han, Jin-Ling Qi, Jia Huang, Ke-Ke Zhang, Can Chen, Xiong-Tao Yang, Dong-Jie Hou, Yu-Sa Wang, Rui Qiao, Xiang Ma, Xiao-Bo Li, Ping Wang, Xin-Ying Song, Li-Ming Song, Shi-Jie Zheng, Bing Li, Hong-Mei Zhang, Yue Zhu, Wei Chen, Jian-Jian He, Zhen Zhang, Jin Hou, Hong-Jun Wang, Yan-Chao Hao, Xiang-Yu Wang, Zong-Yuan Yang, Zhi-Long Wen, Zhi Chang, Yuan-Yuan Du, Rui Gao, Xiao-Fei Lan, Yan-Guo Li, Gang Li, Xu-Fang Li, Fang-Jun Lu, Hong Lu, Bin Meng, Feng Shi, Hui Wang, Hui-Zhen Wang, Yu-Peng Xu, Jia-Wei Yang, Xue-Juan Yang, Shuang-Nan Zhang, Chao-Yue Zhang, Cheng-Mo Zhang, Zhi-Cheng Tang, Cheng Cheng","doi":"10.1088/1674-4527/ad683c","DOIUrl":"https://doi.org/10.1088/1674-4527/ad683c","url":null,"abstract":"Realtime trigger and localization of bursts are the key functions of GECAM, an all-sky gamma-ray monitor launched on 2020 December 10. We developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic Box. This onboard software has the following features: high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation, dedicated localization algorithm optimized for both short and long bursts, and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation system. This paper provides a detailed description of the design and development of the trigger and localization software system for GECAM. It covers the general design, workflow, the main functions, and the algorithms used in the system. The paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube, as well as an overview of the performance for real celestial bursts during its in-orbit operation.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Relation Between Symmetry of Radio Galaxies and Their Physical Parameters","authors":"Mohsen Javaherian, Halime Miraghaei, Hooman Moradpour","doi":"10.1088/1674-4527/ad6c95","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6c95","url":null,"abstract":"Gravity as a fundamental force plays a dominant role in the formation and evolution of cosmic objects and leaves its effect in the emergence of symmetric and asymmetric structures. Thus, analyzing the symmetry criteria allows us to uncover mechanisms behind the gravity interaction and understand the underlying physical processes that contribute to the formation of large-scale structures such as galaxies. We use a segmentation process using intensity thresholding and the <italic toggle=\"yes\">k</italic>-means clustering algorithm to analyze radio galaxy images. We employ a symmetry criterion and explore the relation between morphological symmetry in radio maps and host galaxy properties. Optical properties (stellar mass, black hole mass, optical size (<italic toggle=\"yes\">R</italic>\u0000₅₀), concentration, stellar mass surface density (<italic toggle=\"yes\">μ</italic>\u0000₅₀), and stellar age) and radio properties (radio flux density, radio luminosity, and radio size) are considered. We found that there is a correlation between symmetry and radio size, indicating larger radio sources have smaller symmetry indices. Therefore, size of radio sources should be considered in any investigation of symmetry. Weak correlations are also observed with other properties, such as <italic toggle=\"yes\">R</italic>\u0000₅₀ for FRI galaxies and stellar age. We compare the symmetry differences between FRI and FRII radio galaxies. FRII galaxies show higher symmetry in 1.4 GHz and 150 MHz maps. Investigating the influence of radio source sizes, we discovered that this result is independent of the sizes of radio sources. These findings contribute to our understanding of the morphological properties and analyses of radio galaxies.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Completeness of Accreting Neutron Star Binary Candidates from the Chinese Space Station Telescope","authors":"Hao Shen, Shun-Yi Lan, Xiang-Cun Meng","doi":"10.1088/1674-4527/ad6bd6","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6bd6","url":null,"abstract":"A neutron star (NS) has many extreme physical conditions, and one may obtain some important information about an NS via accreting neutron star binary (ANSB) systems. The upcoming Chinese Space Station Telescope (CSST) provides an opportunity to search for a large sample of ANSB candidates. Our goal is to check the completeness of the potential ANSB samples from CSST data. In this paper, we generate some ANSBs and normal binaries under the CSST photometric system by binary evolution and binary population synthesis method and use a machine learning method to train a classification model. Although the Precision (94.56%) of our machine learning model is as high as before study, the Recall is only about 63.29%. The Precision/Recall is mainly determined by the mass transfer rate between the NSs and their companions. In addition, we also find that the completeness of ANSB samples from CSST photometric data by the machine learning method also depends on the companion mass and the age of the system. ANSB candidates with a low initial mass companion star (0.1 <italic toggle=\"yes\">M</italic>\u0000_⊙ to 1 <italic toggle=\"yes\">M</italic>\u0000_⊙) have a relatively high Precision (94.94%) and high Recall (86.32%), whereas ANSB candidates with a higher initial mass companion star (1.1 <italic toggle=\"yes\">M</italic>\u0000_⊙ to 3 <italic toggle=\"yes\">M</italic>\u0000_⊙) have similar Precision (93.88%) and quite low Recall (42.67%). Our results indicate that although the machine learning method may obtain a relatively pure sample of ANSBs, a completeness correction is necessary for one to obtain a complete sample.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"24 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopic Observations of Ten Galactic Wolf–Rayet Stars at Bosscha Observatory: Determination of Stellar Parameters and Mass-loss Rates","authors":"Hakim Luthfi Malasan, Bakuh Danang Setyo Budi","doi":"10.1088/1674-4527/ad6a39","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6a39","url":null,"abstract":"We present optical spectra of 10 Galactic Wolf–Rayet (WR) stars that consist of five WN and five WC stars. The optical observation was conducted using a low-resolution spectrograph <monospace>NEO-R1000</monospace> (<italic toggle=\"yes\">λ</italic>/Δ<italic toggle=\"yes\">λ</italic> ∼ 1000) at GAO-ITB RTS (27.94 cm, F/10.0), Bosscha Observatory, Lembang. We implemented stellar atmosphere Postdam Wolf–Rayet (<monospace>PoWR</monospace>) grid modeling to derive stellar parameters. The normalized optical spectrum can be used to find the best model from the available <monospace>PoWR</monospace> grid, then we could derive stellar temperature and transformation radius. To derive luminosity, stellar radius and color excess, we conducted a Spectral Energy Distribution (SED) analysis with additional data on the near-ultraviolet spectrum from the International Ultraviolet Explorer (<monospace>IUE</monospace>) database, and <italic toggle=\"yes\">UBV</italic> and 2MASS <italic toggle=\"yes\">JHK</italic> broadband filter data. Additional analysis to derive asymptotic terminal wind velocity was conducted from the P-Cygni profile analysis of the high-resolution <monospace>IUE</monospace> ultraviolet spectrum. With previously derived parameters, we could determine the mass loss rate of the WR stars. Furthermore, we compared our results with previous work that used <monospace>PoWR</monospace> code and the differences are not more than 20%. We conclude that the <monospace>PoWR</monospace> spectral grid is sufficient to derive WR stellar parameters quickly and could provide more accurate initial parameter input to the <monospace>PoWR</monospace> program code.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The FRB-searching Pipeline of the Tianlai Cylinder Pathfinder Array","authors":"Zijie Yu, Furen Deng, Shijie Sun, Chenhui Niu, Jixia Li, Fengquan Wu, Wei-Yang Wang, Yougang Wang, Shifan Zuo, Lin Shu, Jie Hao, Xiaohui Liu, Reza Ansari, Ue-Li Pen, Albert Stebbins, Peter Timbie, Xuelei Chen","doi":"10.1088/1674-4527/ad5b35","DOIUrl":"https://doi.org/10.1088/1674-4527/ad5b35","url":null,"abstract":"This paper presents the design, calibration, and survey strategy of the Fast Radio Burst (FRB) digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder Array. The array, consisting of three parallel cylindrical reflectors and equipped with 96 dual-polarization feeds, is a radio interferometer array designed for conducting drift scans of the northern celestial semi-sphere. The FRB digital backend enables the formation of 96 digital beams, effectively covering an area of approximately 40 square degrees with the 3 dB beam. Our pipeline demonstrates the capability to conduct an automatic search of FRBs, detecting at quasi-real-time and classifying FRB candidates automatically. The current FRB searching pipeline has an overall recall rate of 88%. During the commissioning phase, we successfully detected signals emitted by four well-known pulsars: PSR B0329+54, B2021+51, B0823+26, and B2020+28. We report the first discovery of an FRB by our array, designated as FRB 20220414A. We also investigate the optimal arrangement for the digitally formed beams to achieve maximum detection rate by numerical simulation.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"21 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141872522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-field Split Curvature Wavefront Sensing and its Application in the Large Field Survey Telescope","authors":"Zhixu Wu, Yiming Zhang, Jianan Cong, Hua Bai, Yong Xia, Rongxin Tang, Ming Li, Zhengyang Li and Xiangyan Yuan","doi":"10.1088/1674-4527/ad51d0","DOIUrl":"https://doi.org/10.1088/1674-4527/ad51d0","url":null,"abstract":"The image quality of a large field survey telescope with a fast focal ratio of the primary mirror is high sensitivity to the optical elements’ misalignments and the primary mirror’s deformations. To maintain good optical performance, the perturbations need to be aligned, and the tomographic reconstruction of these perturbations can be derived from wavefront sensing with multi-field points for alignment. This work undertakes a comprehensive examination related to the implementation and optimization of a multi-field split curvature wavefront sensing system, including defocus distance, signal pre-processing, deblending of overlapped doughnuts, field-dependent correction, and distorted coordinate correction. We also conduct experiments to demonstrate the application and performance of a multi-field split curvature wavefront sensing system in Mephisto. In the context of the decentering of the secondary mirror, the coefficient of determination (R) attains a high value of 0.993, indicating a robust linearity between the coma coefficients and the decentering of the secondary mirror. A comparative analysis of the simulated and experimental results shows that the difference between them is less than 0.1 λ.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"424 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}