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Dark energy effects on surface gravitational redshift and Keplerian frequency of neutron stars

Communications in Theoretical Physics 2025年第1期77卷 122-129页

作者： Jia-Jing He Yan Xu Yi-Bo Wang Xiu-Lin Huang Xing-Xing Hu Yu-Fu Shen Changchun observatory National Astronomical ObservatoriesChinese Academy of SciencesChangchun 130117China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China

Research on the properties of neutron stars with dark energy is a particularly interesting yet unresolved problem in *** analyze the influence of dark energy on the equation of state,the maximum mass,the surface gravitational redshift and the Keplerian frequency for the traditional neutron star and the hyperon star matter within the relativistic mean field theory,using the GM1 and TM1 parameter sets by considering the two flavor symmetries of SU(6)and SU(3)combined with the observations of PSR J1614-2230,PSR J0348+0432,PSR J0030+0451,RX J0720.4-3125,and 1E *** is found that the existence of dark energy leads to the softened equations of the state of the traditional neutron star and the hyperon *** radius of a fixed-mass traditional neutron star(or hyperon star)with dark energy becomes smaller,which leads to increased *** existence of dark energy can also enhance the surface gravitational redshift and the Keplerian frequency of traditional neutron stars and hyperon *** growth of the Keplerian frequency may cause the spin rate to speed up,which may provide a possible way to understand and explain the pulsar glitch ***,we infer that the mass and the surface gravitational redshift of PSR J1748-2446ad without dark energy for the GM1(TM1)parameter set are 1.141 M_(☉)(1.309 M_(☉))and 0.095(0.105),*** corresponding values for the GM1(TM1)parameter set are 0.901 M_(☉)(1.072M_(☉))and 0.079(0.091)if PSR J1748-2446ad contains dark energy withα=*** J1748-2446ad may be a low-mass pulsar with a lower surface gravitational redshift under our selected models.

关键词： dark energy neutron stars gravitational redshift Keplerian frequency

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Temporal-spatial distribution of YSOs nearby Taurus region

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Science China(Physics,Mechanics & Astronomy) 2025年第04期Mechanics & Astronomy) .卷 257-266页

作者： Jiaming Liu Min Fang Chao Liu Xiaolong Wang Wenyuan Cui Licai Deng College of Physics Hebei Advanced Thin Films Laboratory Hebei Normal University Shijiazhuang Key Laboratory of Astronomy and Space Science Hebei Normal University Purple Mountain observatory Chinese Academy of Sciences Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences

The Taurus region is one of the most extensively studied star-forming regions （SFRs）.Surveys indicate that the young stars in this region are comprised of young stellar objects （YSOs） that cluster in groups associated with the molecular cloud （Grouped Young Stellar Objects,GYSOs）,and some older ones that are sparsely distributed throughout the region （Distributed Young Stellar Objects,DYSOs）.To bridge the age gap between the GYSOs （5 Myr） and the DYSOs （10-20 Myr）,we conducted a survey to search for new YSOs in this *** on infrared color excesses and Li I absorption lines,we identified 145 new *** these with the previously identified GYSOs and DYSOs,we constructed a sample of 519 YSOs that encompass the entire ***,we calculated the ages of the samples based on their proximity to the local *** age versus distance to the local bubble (DLB) relationship for the DYSOs shows a clear trend:the farther they are from the local bubble,the younger they are,which is consistent with the supernovae-driven formation scenario of the local *** GYSOs also exhibit a mild age versus ***,they are significantly younger and are mostly confined to distances of 120 to 220 *** their distribution in the age versus DLBspace is well separated from the older DYSOs,they may also be products of the local bubble but formed in more recent and localized events.

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Tetrahedron constellation of gravitational wave observatory

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 86-93页

作者： Hong-Bo Jin Cong-Feng Qiao national astronomical observatories Chinese Academy of SciencesBeijing 100101China International Centre for Theoretical Physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

For the first time,we have introduced the tetrahedron constellation of gravitational wave observatory(TEGO)composed of four identical spacecrafts(S/Cs).The laser telescopes and their pointing structures are mounted on the S/C platform and are evenly distributed at three locations 120 degrees *** structures form automatically a stable mass center for the *** time delay interferometry(TDI)is used to suppress the frequency noise of gravitational wave(GW)*** unequal-arm Michelson TDI configuration and the Sagnac TDI configuration are equally effective at eliminating the laser frequency noise based on the TEGO ***,compared with the configurations of LISA,Taiji,and Tian Qin,the TEGO has more combinations of optical paths in its TDI system sensitive to GW *** six arms of TEGO are simultaneously sensitive to the six polarization modes of *** sensitivity implies that GW modes beyond the predictions of general relativity(GR)can be detected *** instance,a scalar longitudinal mode of GWs,which is not predicted by GR,has been identified as a dominant polarization *** mode is found to be evident in the response amplitudes of the TEGO arms,such as between S/C1 and S/C4,and S/C3 and S/C4,at certain orbital positions.

关键词： gravitational wave detectors and experiments gravitational waves experimental tests of gravitational theories experimental studies of gravity

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Relay Observation Scheduling of Global Distributed Telescope Array Based on Integer Programming

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Research in Astronomy and Astrophysics 2025年第1期25卷 211-227页

作者： Junhan Ju Ce Yu Yi Hu Yajie Zhang Chao Sun Jizeng Wei College of Intelligence and Computing Tianjin University Technical R&D Innovation Center National Astronomical Data Center national astronomical observatories Chinese Academy of Sciences

Certain transients require regular observations over several days at intervals of hours or shorter,which cannot be accomplished by telescopes at a single *** deployment of globally distributed telescopes at geographic locations of different longitudes enables the periodic monitoring of transients through relay ***,the simultaneous relay observation of numerous targets requires a telescope array of multiple telescopes that can be efficiently coordinated,and an automated scheduler for the *** paper proposes IPROS,an integer programming model relay observation scheduler for a telescope array,that accounts for the entire process of relay observation and is consistent with the practical *** introduce the integer programming mathematical model for the relay observation scheduling problem with the telescope array,upon which the scheduler is ***,we propose an algorithm to provide a comprehensive formulation of the optimization objective of minimizing cadence deviation in the *** results demonstrate that the relay observation scheduler based on the integer programming model can effectively address the telescope array relay observation *** shows superiority over a scheduler with non-specific consideration of relay observation in the modeling and a scheduler based on greedy thought.

关键词： methods: data analysis surveys techniques: miscellaneous telescopes

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BYSpec: An Automatic Data Reduction Package for BFOSC and YFOSC Spectroscopic Data

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Research in Astronomy and Astrophysics 2025年第2期25卷 184-198页

作者： Zi-Chong Zhang Jun-Bo Zhang Ju-Jia Zhang De-Yang Song Jing Chen Ming-Yi Ding Nan Zhou Liang Wang Kai Zhang Nanjing Institute of astronomical and Optics & Technology Chinese Academy of Sciences CAS Key Laboratory of astronomical Optics & Technology Nanjing Institute of Astronomical Optics & Technology University of Chinese Academy of Sciences CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences yunnan observatories Chinese Academy of Sciences International Centre of Supernovae Yunnan Key Laboratory

BFOSC and YFOSC are the most frequently used instruments in the Xinglong 2.16 m telescope and Lijiang 2.4 m telescope, respectively. We developed a software package named “BYSpec”(BFOSC and YFOSC Spectra Reduction Package) dedicated to automatically reducing the long-slit and echelle spectra obtained by these two instruments. The package supports bias and flat-fielding correction, order location, background subtraction, automatic wavelength calibration, and absolute flux calibration. The optimal extraction method maximizes the signal-to-noise ratio and removes most of the cosmic rays imprinted in the spectra. A comparison with the 1D spectra reduced with IRAF verifies the reliability of the results. This open-source software is publicly available to the community.

关键词： instrumentation: spectrographs methods: data analysis techniques: image processing

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First Search for Pulsed CH Maser Emission Stimulated by a Pulsar

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Research in Astronomy and Astrophysics 2025年第2期25卷 62-71页

作者： Mengting Liu Di Li J.R.Dawson Joel M.Weisberg George Hobbs Ningyu Tang Gan Luo Duo Xu Donghui Quan Research Center for astronomical Computing Zhejiang Laboratory Department of Astronomy Tsinghua University national astronomical observatories Chinese Academy of Sciences CSIRO Astronomy & Space Science Australia Telescope National Facility School of Mathematical and Physical Sciences and Astrophysics and Space Technologies Research Centre Macquarie University Department of Physics and Astronomy Carleton College Department of Physics Anhui Normal University Institut de Radioastronomie Millimetrique 300 Rue de la Piscine Canadian Institute for Theoretical Astrophysics University of Toronto 60 St.George Street

We present the first search for pulsed CH maser emission potentially stimulated by PSR J1644-4559,conducted using the ultra-wide-bandwidth low-frequency receiver on Murriyang,CSIRO's Parkes Radio *** targeted three CHΛ-doublet transitions at 3264,3335,and 3349 MHz,with a variability timescale of78 *** detected ten CH emission features at 3335 and 3349 MHz,and seven features at 3264 MHz,during both pulsar-ON and pulsar-OFF *** observed velocities align with the OH emission and absorption reported by a previous study,suggesting a close spatial association between CH and OH *** derived column densities for CH clouds within the Parkes beam range from 0.05 to 9.8×1013cm-2,indicating that these clouds are likely in diffuse and translucent *** limits for CH column densities within the pulsar beam ranged from 0.3 to 9.8×*** of these column densities suggests that CH clouds may exhibit clumpiness and *** significant stimulated emission feature was detected in the optical depth ***,as part of our search for pulsed stimulated emission,we investigated the potential CH absorption of the pulsar signal and found none,in agreement with astrophysical *** upper limits for the potential maser amplification factors towards PSR J1644-4559 at 3264,3335,and 3349 MHz are 1.014,1.009,and 1.009,*** study demonstrates the feasibility of detecting pulsed CH maser emission in the interstellar medium stimulated by pulsar photons.

关键词： (stars:) pulsars: general ISM: molecules masers

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Core Mass Function in View of Fractal and Turbulent Filaments and Fibers

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Research in Astronomy and Astrophysics 2025年第2期 208-215页

作者：刘训川 Tie Liu Xiaofeng Mai Yu Cheng Sihan Jiao Wenyu Jiao Hongli Liu Siju Zhan Shanghai astronomical observatory Chinese Academy of Sciences Leiden observatory Leiden University Department of Physics University of Helsinki national astronomical observatory of Japan national astronomical observatories Chinese Academy of Sciences School of Physics and Astronomy Yunnan University Departamento de Astronomía Universidad de Chile

We propose that the core mass function(CMF) can be driven by filament fragmentation. To model a star-forming system of filaments and fibers, we develop a fractal and turbulent tree with a fractal dimension of 2 and a Larson's law exponent(β) of 0.5. The fragmentation driven by convergent flows along the splines of the fractal tree yields a Kroupa-IMF-like CMF that can be divided into three power-law segments with exponents α =-0.5,-1.5, and-2, respectively. The turnover masses of the derived CMF are approximately four times those of the Kroupa IMF,corresponding to a star formation efficiency of 0.25. Adopting β = 1/3, which leads to fractional Brownian motion along the filament, may explain a steeper CMF at the high-mass end, with α =-3.33 close to that of the Salpeter IMF. We suggest that the fibers of the tree are basic building blocks of star formation, with similar properties across different clouds, establishing a common density threshold for star formation and leading to a universal CMF.

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A Method to Assess the Applicability and Accuracy of the Modified Gaussian Model(MGM) on the Rock Samples' Spectral Interpretation

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Research in Astronomy and Astrophysics 2025年第1期25卷 175-183页

作者： Fang Gao Bin Liu Qin Zhou Chun-Lai Li Key Laboratory of Lunar and Deep Space Exploration Chinese Academy of Sciences national astronomical observatories Chinese Academy of Sciences University of Chinese Academy of Sciences

The Chang’e-4 mission obtained spectral data of multiple rock targets on the lunar *** Modified Gaussian Model (MGM) is usually applied to the spectral interpretation of powder samples,its applicability and accuracy on the rock targets remain to be further *** rock slice of lunar meteorite NWA 4734 is used to conduct comprehensive analysis of the petrography,mineralogy and laboratory spectroscopy,which will provide important ground truth for the MGM interpretation of lunar in situ spectra of rock ***,a scanning electron microscope (SEM),Energy Dispersive Spectrometer (EDS),and Electron Probe Micro-Analyzer (EPMA) analysis results indicate that:(1) almost all plagioclase in NWA 4734 have been converted to maskelynites,which indicate that the meteorite has undergone severe impact metamorphism;(2) the chemical composition of pyroxene and olivine is significantly heterogeneous,showing a distribution characteristic of magnesium-rich core and iron-rich rim,further indicating that NWA 4734 has undergone multiple crystallization and ***,this article focuses on the rock slice of NWA 4734's greyscale image of the Back Scattering Electron (BSE),and obtains the proportion of High-Calcium Pyroxene (HCP) in the total pyroxenes of this sample by calculating the area percentage using the pixel counting *** result shows that the proportion of HCP is 72%±5.4%,which can be used as a ground truth to evaluate the interpretation applicability and accuracy of MGM.A field spectrometer (ASD) is used to measure the visible and near-infrared reflectance spectra (450–2500 nm) of the rock slice from NWA 4734 in the same area as the BSE image obtained by SEM,and MGM is used to deconvolve the ASD spectra,and the average proportion of HCP is estimated to be 71%±10.1%.The results between the MGM and the pixel counting are comparable within the error range,which demonstrates the applicability of MGM on interpretation of the rock samples on the lu

关键词： astrochemistry instrumentation: spectrographs methods: data analysis

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Sky location of massive black hole binaries in the foreground of Galactic white dwarf binaries

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 93-104页

作者： Pan Guo Hong-Bo Jin Cong-Feng Qiao Yue-Liang Wu The International Centre for Theoretical Physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100190China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China national astronomical observatories Chinese Academy of SciencesBeijing 100101China The School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China

For space-based gravitational wave(GW)detection,the main noise source for massive black hole binaries(MBHBs)is attributed to approximately 107 double white dwarf binaries in the *** a GW source,the amplitude of the detector response,recorded by a space-based gravitational wave detector,exhibits a modulation effect with a year period when observing the source from various orbital *** the adverse conditions mentioned above,where there is a strong foreground noise and annual modulation in the signals,we employed the wavelet transform and the strong-amplitude relevant orbital position search methods,which allows the weak MBHB sources to achieve higher locating *** detail,for two MBHB sources of lower intensity,the precision of luminosity distance,represented by the ratioΔD_(L)/D_(L) at the 95%confidence level,is enhanced by factors of∼*** angular resolutions,denoted byΔΩs,are enhanced by a factor of∼*** improvements increase the number of detectable GW sources,facilitate multi-messenger follow-up observations and provide constraints on the cosmological constant.

关键词： space-based gravitational wave detection gravitational waves massive black hole binaries

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The coronal magnetic field reversal observed by the SOLARC instrument

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1696-1701页

作者： LIU Yu SHEN YuanDeng yunnan astronomical observatory/national astronomical observatories Kunming 650011China

High-sensitivity measurements for mapping coronal magnetic field have become possible since the recent development of infrared detection techniques. One urgent task that arises from the routine infrared observations is to interpret what the Stokes signals could indicate for coronal magnetic fields. It is the first time for us to successfully reveal the coronal field structure above a simple and stable sunspot on the photosphere using profiles of full Stokes parameters. In this paper, the author further points out the deficiency in any conclusions/judgements just based on incomplete polarization data. A magnetic flux reversal feature, observed from circular polarization data, may correspond to one or more coronal tubes with their front or farside arching apex there, more complicated than people imagined before. To exactly locate the infrared radiation sources, we need both circular and linear polarization data for an integrated analysis of them.

关键词： solar corona magnetic field infrared wavelength extrapolation

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