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Application of 3D U-Net Neural Networks in Extracting the Epoch of Reionization Signal from SKA-Low Observations Based on Real Observations of NCP Field from LOFAR

arXiv

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arXiv 2024年

作者： Gao, Li-Yang Koopmans, Léon V.E. Mertens, Florent G. Munshi, Satyapan Li, Yichao Brackenhoff, Stefanie A. Ceccotti, Emilio Chege, J. Kariuki Acharya, Anshuman Ghara, Raghunath Giri, Sambit K. Iliev, Ilian T. Mellema, Garrelt Zhang, Xin Liaoning Key Laboratory of Cosmology and Astrophysics College of Sciences Northeastern University Shenyang110819 China Kapteyn Astronomical Institute University of Groningen P.O. Box 800 Groningen9700 AV Netherlands LERMA Observatoire de Paris Université PSL CNRS Sorbonne Université ParisF-75014 France INAF - Istituto di Radioastronomia Via P. Gobetti 101 Bologna40129 Italy Max-Planck-Institut für Astrophysik Garching85748 Germany Department of Physical Sciences Indian Institute of Science Education and Research Mohanpur WB Kolkata741246 India Van Swinderen Institute for Particle Physics and Gravity University of Groningen Nijenborgh 4 Groningen9747 AG Netherlands Department of Physics & Astronomy University of Sussex BrightonBN1 9QH United Kingdom Dept. of Astronomy & Oskar Klein Centre Stockholm University AlbaNova Stockholm University StockholmSE-106 91 Sweden MOE Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China

Neutral hydrogen (HI) serves as a crucial probe for the Cosmic Dawn and the Epoch of Reionization (EoR). Actual observations of the 21-cm signal often encounter challenges such as thermal noise and various systematic effects. To overcome these challenges, we simulate SKA-Low-depth images and process them with a deep learning method. We utilized foreground residuals acquired by LOFAR during actual North Celestial Pole (NCP) field observations, thermal and excess variances calculated via Gaussian process regression (GPR), and 21-cm signals generated with 21cmFAST for signal extraction tests. Our approach to overcome these foreground, thermal noise, and excess variance components employs a 3D U-Net neural network architecture for image analysis. When considering thermal noise corresponding to 1400 hours of integration, U-Net provides reliable 2D power spectrum predictions, and robustness tests ensure that we get realistic EoR signals. Adding foreground residuals, however, causes inconsistencies below the horizon delay-line. Lastly, evaluating both thermal and excess variance with observations up to 3700 and 14000 hours ensures reliable power spectrum estimations within the EoR window and across nearly all scales, respectively. Copyright © 2024, The Authors. All rights reserved.

关键词： Thermal noise

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Effects of Small-Scale Absorption Systems on Neutral Islands during the Late Epoch of Reionization

arXiv

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arXiv 2021年

作者： Wu, Peng-Ju Xu, Yidong Zhang, Xin Chen, Xuelei Department of Physics College of Sciences Northeastern University Shenyang110819 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Key Laboratory of Data Analytics and Optimization for Smart Industry Ministry of Education Northeastern University Shenyang110819 China Center for High Energy Physics Peking University Beijing100871 China University of Chinese Academy of Sciences Beijing100049 China

The reionization process is expected to be prolonged by the small-scale absorbers (SSAs) of ionizing photons, which have been seen as Lyman-limit systems in quasar absorption line observations. We use a set of semi-numerical simulations to investigate the effects of absorption systems on the reionization process, especially their impacts on the neutral islands during the late Epoch of Reionization (EoR). Three models are studied, i.e. the extreme case of no-SSA model with a high level of ionizing background, the moderate-SSA model with a relatively high level of ionizing background, and the dense-SSA model with a low level of ionizing background. We find that while the characteristic scale of neutral regions decreases during the early and middle stages of reionization, it stays nearly unchanged at about 10 comoving Mpc during the late stage for the no-SSA and moderate-SSA models. However, in the case of weak ionizing background in the dense-SSA model, the characteristic island scale shows obvious evolution, as large islands break into many small ones that are slowly ionized. The evolutionary behavior of neutral islands during the late EoR thus provides a novel way to constrain the abundance of SSAs. We discuss the 21-cm observation with the upcoming Square Kilometre Array. The different models can be distinguished by either the 21-cm imaging or the 21-cm power spectrum measurements. Copyright © 2021, The Authors. All rights reserved.

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A novel method of measuring cosmological distances using broad-line regions of quasars

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Science Bulletin 2020年第17期65卷 1419-1421页

作者： Hong Li Xin Zhang Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Ministry of Education’s Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern UniversityShenyang 110819China Center for High Energy Physics Peking UniversityBeijing 100080China Center for Gravitation and Cosmology Yangzhou UniversityYangzhou 225009China

Our ancestors,such as Cro-Magnon,always looked up at the stars and wished to understand the mysteries of the universe,but their view of the universe was probably quite simple:the stars are inlaid on the inner surface of the sky,and they are very ***,now we know that stars and galaxies are actually extreextremely huge,and they look small because they are too far away from *** indicates that the measurement of cosmological distance is always very important in the study of the universe.

关键词： stars universe 类星体

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Dark energy and matter interacting scenario to relieve H0 and S8 tensions

arXiv

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arXiv 2022年

作者： Gao, Li-Yang Xue, She-Sheng Zhang, Xin Department of Physics College of Sciences Northeastern University Shenyang110819 China Kapteyn Astronomical Institute University of Groningen P.O. Box 800 Groningen9700 AV Netherlands ICRANet Piazzale della Repubblica Pescara10-65122 Italy ICTP-AP University of Chinese Academy of Sciences Beijing China Physics Department Sapienza University of Rome P.le A. Moro 5 Rome00185 Italy INFN Sezione di Perugia Via A. Pascoli PerugiaI-06123 Italy Key Laboratory of Data Analytics and Optimization for Smart Industry Ministry of Education Northeastern University Shenyang110819 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China

We consider a new cosmological model (called Λ˜CDM) in which the vacuum energy interacts with matter and radiation, and test this model using the current cosmological observations. Using the CMB+BAO+SN (CBS) dataset to constrain the model, we find that H0 and S8 tensions are relieved to 2.87σ and 2.77σ, respectively. However, in this case, the Λ˜CDM model is not favored by the data, compared with ΛCDM. We find that when the H0 and S8 data are added to the data combination, the situation is significantly improved. In the CBS+H0 case, the model relieves the H0 tension to 0.47σ, and the model is favored over ΛCDM. In the CBS+H0+S8 case, we obtain a synthetically best situation, in which the H0 and S8 tensions are relieved to 0.72σ and 2.11σ, respectively. In this case, the model is most favored by the data. Therefore, this cosmological model can greatly relieve the H0 tension and simultaneously effectively alleviate the S8 tension. Copyright © 2022, The Authors. All rights reserved.

关键词： Electric circuit breakers

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FAST drift scan survey for Hi intensity mapping: I. preliminary data analysis

arXiv

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arXiv 2023年

作者： Li, Yichao Wang, Yougang Deng, Furen Yang, Wenxiu Hu, Wenkai Liu, Diyang Zhao, Xinyang Zuo, Shifan Shu, Shuanghao Li, Jixia Timbie, Peter Ansari, Réza Perdereau, Olivier Stebbins, Albert Wolz, Laura Wu, Fengquan Zhang, Xin Chen, Xuelei College of Sciences Northeastern University Shenyang110819 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China Aix Marseille Univ CNRS CNES LAM Marseille France Australia Department of Physics University of Wisconsin – Madison MadisonWI53706 United States Université Paris-Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette91191 France Université Paris-Saclay CNRS IN2P3 IJCLab Orsay91405 France Fermi National Accelerator Laboratory P.O. Box 500 BataviaIL60510 United States Jodrell Bank Centre for Astrophysics Department of Physics & Astronomy The University of Manchester ManchesterM13 9PL United Kingdom National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China Key Laboratory of Data Analytics and Optimization for Smart Industry Ministry of Education Northeastern University Shenyang110819 China

This work presents the initial results of the drift-scan observation for the neutral hydrogen (Hi) intensity mapping survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The data analyzed in this work were collected in night observations from 2019 through 2021. The primary findings are based on 28 hours of drift-scan observation carried out over seven nights in 2021, which covers 60 deg2 sky area. Our main findings are: (i) Our calibration strategy can successfully correct both the temporal and bandpass gain variation over the 4-hour drift-scan observation. (ii) The continuum maps of the surveyed region are made with frequency resolution of 28 kHz and pixel area of 2.95 arcmin2. The pixel noise levels of the continuum maps are slightly higher than the forecast assuming Tsys = 20 K, which are 36.0 mK (for 10.0 s integration time) at the 1050–1150 MHz band, and 25.9 mK (for 16.7 s integration time) at the 1323–1450 MHz band, respectively. (iii) The flux-weighted differential number count is consistent with the NRAO-VLA Sky Survey (NVSS) catalog down to the confusion limit ∼ 7 mJy/beam−1. (iv) The continuum flux measurements of the sources are consistent with that found in the literature. The difference in the flux measurement of 81 isolated NVSS sources is about 6.3%. Our research offers a systematic analysis for the FAST Hi intensity mapping drift-scan survey and serves as a helpful resource for further cosmology and associated galaxies sciences with the FAST drift-scan survey. Copyright © 2023, The Authors. All rights reserved.

关键词： data handling

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optimization of the raw material field layout for iron-steel enterprise

Optimization of the raw material field layout for iron-steel...

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作者： Wenbo Liu Yuehong Kong Department of Logistics Management Liaoning Provincial College of Communications Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University)

This paper studies a short-term layout optimization problem with the raw material field for iron-steel *** raw material field is a centralized storage place and distribution unit of various raw materials such as iron ore,which plays a significant role in the iron front logistics for iron and steel *** the stacking of raw materials is reasonable or not directly affects the logistics efficiency and logistics cost of raw materials for iron-steel *** on the status and basic information of the raw materials,storage space of the field shall be made full use of to allocate the optimal position for each type of raw *** achieve this goal,a mixed integer programming(MIP) model is developed,which is purposed to minimize the transportation cost and the loss of *** solution compares favorably with the current practice in the iron-steel enterprises.

关键词： workshop optimization of the raw material field layout for iron-steel enterprise

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Holographic p-wave superconductivity from higher derivative theory

arXiv

引用

arXiv 2020年

作者： Liu, Yan Fu, Guoyang Li, Hai-Li Wu, Jian-Pin Zhang, Xin College of Sciences MOE Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China Center for Gravitation and Cosmology College of Physical Science and Technology Yangzhou University Yangzhou225009 China School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai200240 China

We construct a holographic SU(2) p-wave superconductor model with Weyl corrections. The high derivative (HD) terms do not seem to spoil the generation of the p-wave superconducting phase. We mainly study the properties of AC conductivity, which is absent in holographic SU(2) p-wave superconductor with Weyl corrections. The conductivities in superconducting phase exhibit obvious anisotropic behaviors. Along y direction, the conductivity σyy is similar to that of holographic s-wave superconductor. The superconducting energy gap exhibits a wide extension. For the conductivity σxx along x direction, the behaviors of the real part in the normal state are closely similar to that of σyy. However, the anisotropy of the conductivity obviously shows up in the superconducting phase. A Drude-like peak at low frequency emerges in Reσxx once the system enters into the superconducting phase, regardless of the behaviors in normal state. Copyright © 2020, The Authors. All rights reserved.

关键词： Holography

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A novel PSDE algorithm for multi-objective optimization

A novel PSDE algorithm for multi-objective optimization

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第三十八届中国控制会议

作者： Meiling Xu Hongxin Dong Zaidi Ji Yiwen Wang Key laboratory of Data Analytics and Optimization for Smart Industry Ministry of Education Northeastern University Faculty of Electronic Information and Electrical Engineering Dalian University of Technology

Differential evolution for multi-objective optimization is a useful and straightforward evolutionary optimization algorithm. Since the algorithm randomly searches in problem space, it may get into trouble when we adapt it to solve multi-objective problems. With regard to the limitation of DE, we propose a new algorithm PSDE to solve multi-objective functions based on the PSO operator and DE operator. In this algorithm, we utilize DE operator to promote the uniform spread of solutions and use PSO operator to obtain good local search ability by retaining the best solutions obtained so far. Experimental results on a set of benchmark test functions sustain the effectiveness of the proposed algorithm.

关键词： Differential evolution multi-objective optimization particle swarm optimization

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Forecast for cosmological parameter estimation with gravitational-wave standard siren observation from the Cosmic Explorer

arXiv

引用

arXiv 2020年

作者： Jin, Shang-Jie He, Dong-Ze Xu, Yidong Zhang, Jing-Fei Zhang, Xin Department of Physics College of Sciences Northeastern University Shenyang110819 China Key Laboratory for Computational Astrophysics National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Ministry of Education's Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China Center for High Energy Physics Peking University Beijing100080 China

The third-generation ground-based gravitational-wave (GW) detector, Cosmic Explorer (CE), is scheduled to start its observation in the 2030s. In this paper, we make a forecast for cosmological parameter estimation with gravitational-wave standard siren observation from the CE. We use the simulated GW standard siren data of CE to constrain the ΛCDM, wCDM and CPL models. We combine the simulated GW data with the current cosmological electromagnetic observations including the latest cosmic microwave background anisotropies data from Planck, the optical baryon acoustic oscillation measurements, and the type Ia supernovae observation (Pantheon compilation) to do the analysis. We find that the future standard siren observation from CE will improve the cosmological parameter estimation to a great extent, since the future GW standard siren data can well break the degeneracies generated by the optical observations between various cosmological parameters. We also find that the CE's constraining capability on the cosmological parameters is slightly better than that of the same-type GW detector, the Einstein Telescope. In addition, the synergy between the GW standard siren observation from CE and the 21 cm emission observation from SKA is also discussed. Copyright © 2020, The Authors. All rights reserved.

关键词： Gravity waves

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Impacts of dark energy on constraining neutrino mass after Planck 2018

arXiv

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arXiv 2020年

作者： Zhang, Ming Zhang, Jing-Fei Zhang, Xin Department of Physics College of Sciences Northeastern University Shenyang110819 China Ministry of Education’s Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China Center for High Energy Physics Peking University Beijing100080 China Center for Gravitation and Cosmology Yangzhou University Yangzhou225009 China

Considering the mass splittings of three active neutrinos, we investigate how the nature of dark energy affects the cosmological constraints on the total neutrino mass P mν using the latest cosmological observations. In this paper, some typical dark energy models, including ΛCDM, wCDM, CPL, and HDE models, are discussed. In the analysis, we also consider the effects from the neutrino mass hierarchies, i.e., the degenerate hierarchy (DH), the normal hierarchy (NH), and the inverted hierarchy (IH). We employ the current cosmological observations to do the analysis, including the Planck 2018 temperature and polarization power spectra, the baryon acoustic oscillations (BAO), the type Ia supernovae (SNe), and the Hubble constant H0 measurement. In the ΛCDM+P mν model, we obtain the upper limits of the neutrino mass P mν Copyright © 2020, The Authors. All rights reserved.

关键词： Acoustic intensity measurement

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