Subjects: Astronomy >> Astrophysical processes Subjects: Astronomy >> Astrophysics Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. Subjects: Physics >> Geophysics, Astronomy, and Astrophysics submitted time 2025-07-16
Abstract： Introduction of the Huang Metric, which incorporates a quantum gravity correction term in the metric: \frac{2kG_hM^2(\ln r+1)}{c^2 r}. This unified framework calculates both the black hole event horizon and photon sphere, enabling precise prediction of shadow diameter without requiring a spin parameter (spin is typically a post-observation fitting parameter).
Key Formula:
Huang Metric Horizon Equation:
g_{tt} = 0:r_h = \frac{2GM}{c^2} + \frac{2kG_hM^2(\ln r_h +1)}{c^2}
Results and Observational Verification:Black Hole Theoretical Shadow Diameter (μas) EHT Observation (μas) Agreement
Sgr A* (Milky Way) 43.41 – 53.96 51.8 ± 7 Covers error band
M87* (M87 Galaxy) 38.63 – 46.71 42 ± 3 Fully covered Conclusions:
1. Eliminates spin dependence: Shadow diameter is determined solely by mass M and mass ratio k, with no assumption of black hole spin.
2. Observational evidence for quantum gravity: The logarithmic correction term \ln r—directly reflecting quantum topological effects—is confirmed by EHT data.
3. Analytical calculations replace observational fitting: All results are derived through analytical calculations, significantly improving computational efficiency.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2025-07-09
Abstract： Five decades after the discovery of radio pulsars, main stream theories based on polar cap still suffer from difficulties in both self-consistency and confrontation with observations[1]. Increasing observation of individual subpulses of pulsars, i.e., high brightness temperature, highly polarized, and narrowband nanoshots of the Crab pulsar[2, 3] indicate that they relate with basic emission elements in a pulse window. Moreover, high degree of circular polarization, and rapid orthogonal jump in the position angle of linear polarization are observed in micropulses of both pulsars and Fast Radio Bursts (FRBs)[3–6], which further requires that such a small element of emission has a rapid variable conal-core pattern rather than a simple bunch of high energy density widely accepted. These are both unprecedented challenges and chances to understand the origin of pulsar coherent emission. This paper confronts with those difficulties by a simple model of alternative emission site and mechanism, in which pulsar wind is launched from open field line region and the coherent emission is triggered by a forced magnetic reconnection occurring at the tip of last closed field line near the light cylinder. The high energy density at such a tiny reconnection site automatically invokes Alfven waves, creates electron-positron pair, and accelerates them into relativistic speed. The resultant particle-wave interaction gives rise to coherent bunches inborn a conal-core structure responsible for observations on pulsars, magnetars and FRBs. For the first time, puzzles on coherency, polarization, correlation of coherent emission with wind, and energy budget of pulsars, magnetars, and FRBs are interpreted by a unified model.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Galaxy and Cosmology Subjects: Astronomy >> Galaxy and Cosmology submitted time 2025-07-02
Abstract： It is suggested that the formation of dark matter binaries would produce radiation in the same way that the formation of hydrogen atoms does in HII regions. A hydrogen HII region like the Orion Nebula with its Lyman alpha radiation is considered as a model for dark matter particles combining into binaries. This conjecture is considered in detail and it is found to provide a surprising fit to the Planck data isotropy and dipole. It could be regarded as an alternative explanation. A precise mass for the dark matter particle would be 10.7 ZeV (1.07 x 1013 GeV). Examination of the Plank structure of the CMB also suggests there is further physics to be revealed. Observational tests are suggested to check the role of dark matter in the Galaxy Halo.
Peer Review Status:Awaiting Review
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： The development and operation of automated astronomical data processing pipelines require the ability to automatically acquire the best calibration reference data across various categories, necessitating the emergence of a comprehensive Calibration Ref#2;erence Data System. This paper reviews the various recommendation methods employed by different telescopes worldwide, and analyzes the strengths and weaknesses of each approach.Additionally, it particularly introduces a new text-based rule recommendation strategy, a#2;long with a supporting comprehensive Calibration Reference Data System (CRDS). We also highlight the essential role and potential applications of this system in processing scientific data for the China Space Station survey Telescope (CSST), which is China’s first large-scale space optical astronomical telescope. In conclusion, we provide insightful forecasts on the advancement prospects of this recommendation strategy.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： During the operation of ground-based laser interferometric gravitational wave detectors, the internal optical systems are subject to various noise disturbances, resulting in uncontrollable displacements. To enhance the sensitivity of the detectors and enable the detection of faint gravitational wave signals, it is imperative to employ a length sensing and control system. This system ensures that multiple optical cavities within the detector remain in resonance, thereby facilitating the design of gravitational wave signal readout schemes. Beginning with the configuration of laser interferometric gravitational wave detectors, this paper outlines the fundamental principles of length feedback control and parameter design criteria. Drawing on specific parameters of the Advanced LIGO, Advanced Virgo, and KAGRA control systems currently in operation, a detailed exposition is provided on the working principles and applications of length sensing and control systems in gravitational wave detectors.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： Over the past two years, China has achieved significant breakthroughs in the development of infrared detectors. Guided by the demands of astronomical observation, we have conducted comprehensive tests on all astronomical detection parameters of the infrared detector and obtained key indicators such as readout noise, dark current, full well capacity, dynamic range, nonlinearity, nonuniformity, and quantum efficiency. These tests have enabled us to assess the detector’s capabilities in infrared astronomy. Additionally, we utilized the 1.56 m Telescope at the Shanghai Astronomical Observatory’s Sheshan site for real-world observations. These observations confirmed that the detector’s ground-based application performance is comparable to that of foreign detectors, indicating that China’s infrared astronomy has advanced to a stage where it can employ domestically developed infrared detectors for astronomical observations in specific near-infrared bands.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： The servo system of the radio telescope’s driving motor exhibits speed mismatch during operation, which restricts the high-precision pointing and tracking control of the tele#2;scope. With the aperture of the telescope increases and precision improves, this issue will significantly impact the high-precision control of pointing and tracking for large-aperture radio telescopes. To reduce speed deviations in the servo system and enhance the pointing accuracy of the radio telescope, a robust motor synchronization controller based on mod#2;el predictive control (MPC) is designed. To address external disturbances and unmodeled errors, disturbance observer (DOB) is designed based on the system’s state-space model to estimate total disturbances. Additionally, Luenberger observer (LOB) is designed to esti#2;mate the system’s states. Combining these observers with MPC, quadratic cost function is designed to regulate the load angle and motor speed. This ensures motor speed synchroniza#2;tion while maintaining tracking control effectiveness. Simulation and experimental results demonstrate that compared to conventional proportion-integration (PI) controllers combined with cross-coupled structures (CS), MPC+DOB+LOB enhances the servo system’s dynamic performance and synchronization capabilities.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： As one of the important methods to detect the cosmic reionization epoch, the core goal of the low-frequency all-sky total power experiment is to detect the extremely weak neutral hydrogen 21 cm signal during the cosmic reionization period in the all-sky total power spectrum with a spectrum range of 50∼200 MHz. At present, the fast Fourier transform (FFT) is usually used to calculate the power spectrum, and the spectral leakage problem makes it impossible to completely deduct Radio Frequency Interference (RFI), which seriously interferes with the extraction of weak cosmic reionization signals. Polyphase filter banks (PFB) is a technique that evenly divides signals by frequency, which can replace FFT to calculate the power spectrum. In this paper, the basic principle of PFB and its implementation based on compute unified device architecture (CUDA) are introduced, and the performance of PFB and FFT is compared through simulation, and the performance differences of PFB of different orders are compared. Finally, the measured and experimental data are processed to verify the superiority of PFB technology, which provides an effective solution for the spectrum analysis of the all-sky total power experiment.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： High-amplitude δ scuti stars (HADS), a subclass of δ Scuti pulsating variable stars, are characterized by short pulsation periods, large amplitudes, and single or multiple radial pulsation modes, making them an important target for asteroseismology. In this paper, a frequency analysis of three HADS is performed for the first time using the time-series photometry data provided by the Transiting Exoplanet Survey Satellite (TESS). The result show that TIC 355547586 pulsates at the fundamental frequency and first overtone, and TIC 358502706 at the fundamental frequency, first and third overtone. Non-radial pulsation frequencies were also detected in their frequency spectra. TIC 260654645 is pulsating at fundamental frequency and first overtone. The phase-folding curve of the source has a clear bulge in the brightness-decreasing phase near the luminosity minima, exhibiting the characteristics of a ab-type RR Lyrae, and the period ratio of the first overtone to the fundamental frequency of it is larger than the theoretical prediction for radial pulsation, which, combined with its positional deviation from the HADS pulsation instability band on the Hertzsprung-Russell diagram, makes the star worthy of further study.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： So far, a total of 72 black holes X-ray transients or candidates have been detect#2;ed, of which 19 have been dynamically confirmed. These transients are X-ray binary systems consisting of stellar-mass black holes and low-mass stars. Measurements of the fundamental parameters of stellar-mass black holes significantly aid our understanding of the formation and evolution of black holes, and also provide crucial evidences for ongoing debates in this regime, such as whether there exists a strict mass gap between stellar-mass black holes and neutron stars. This review introduces the fundamental theories of black hole X-ray binaries, discusses the commonly used methods and softwares in the mass measurements of stellar-mass black holes, and analyzes potential sources of errors in the dynamical model#2;ing processes. Finally, the statistical properties of the existing sample of black hole X-ray transients are summarized, and the future research prospects in this field are presented.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： Outflows serve as a crucial feedback mechanism in quasars, playing a significant role in understanding the co-evolution processes between quasars and their host galaxies. This paper collects and organizes literature on the research of velocity shifts in outflow ab#2;sorption lines, compares and analyzes the identification methods, challenges, and generation mechanisms of such velocity shifts, and discusses potential future research directions. While current empirical cases of absorption line velocity shifts are limited and their underlying physical mechanisms remain unclear, the growth of quasar survey data and advancements in data processing techniques are expected to lead to breakthroughs in this field, such progress will not only deepen our understanding of quasar outflows, but also offer new perspectives for galaxy evolution studies.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： Galaxy clusters are the largest self-gravitationally bound systems in the Universe. Their diffuse radio emission is synchrotron radiation generated by non-thermal electrons moving in the magnetic field, and can be mainly classified into radio halos, radio mini-halos and radio relics. Radio halos occur mostly in merging clusters, and their origin is thought to be described by the merger-induced turbulent reacceleration model. Radio mini-halos are of small number and mainly found in relaxed cool-core clusters. Their origin can also be described by the turbulent reacceleration model, except that the turbulence is induced by gas sloshing in the cluster’s core. Radio relics are polarized sources mostly found in clusters’ periphery. They trace merger-induced shock waves. Finally, a larger and deeper survey of diffuse cluster radio sources in the era of LOFAR 2.0 and SKA is discussed.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： Mantle convection plays a key role in the evolution of terrestrial planets. The latest research progress on mantle convection in terrestrial planets and large satellites is reviewed in this paper with the method of comparative planetology, which concentrates on three main issues, which are (1) Does mantle convection exist within terrestrial planets? (2) If mantle convection exists, what are its convection regime and characteristics? (3) What conditions are required for mantle convection to occur in terrestrial planets? The principal factors that significantly influence mantle convection are also discussed, in#2;cluding the mantle geometry and scale, material property, driving mechanism, fluid viscosity, thermal and kinematic boundary conditions, differentiation and phase transformation. It further addresses mantle convection and convection in ice shell of some large satellites. Elu#2;cidating the causes, mechanisms, and effects of mantle convection across different celestial bodies holds significant implications for understanding the planetary internal dynamics and planetary evolutions.
Subjects: Astronomy submitted time 2025-07-02 Cooperative journals: 《天文学进展》
Abstract： This paper provides a comprehensive review of perihelion observations and sig#2;nificant observational events such as ground-based observations of the active asteroid (3200) Phaethon during its close approach to Earth. It summarizes the current research priorities of (3200) Phaethon，followed by an investigation into the mechanisms governing its perihelion activity, in which the highly discussed thermal fracturing and the theory of water ice and Na sublimation driving theory are elaborated in detail. Detailed analyses of spectroscop#2;ic signatures, albedo variations, and polarization measurements are presented to elucidate surface composition and physical characteristics, thereby providing substantial evidence for understanding the asteroid’s surface properties. Phaethon-Geminid Complex (PGC) rela#2;tion discussions and studies such as the classification of active asteroids and the traceability of Phaethon are further summarized. In the study of asteroid dynamical evolution and ther#2;mal physics models, the MERCURY6 integrator was employed on the orbital elements of Phaethon on a millennial timescale to derive the results on the asteroid’s perihelion distance and other orbital characteristics. Additionally, the advanced thermophysical model (ATPM) was applied to fit a compilation of infrared multi-band observational data, yielding estimates for thermal inertia, albedo, and diameter. Finally, JAXA space mission DESTINY+ and China’s upcoming Tianwen-2 mission are discussed.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： Using the high-sensitivity and high-resolution observations of the 12CO (J=1–0, J is angular-momentum quantum number) molecular line observed by the Qinghai Observatory of Purple Mountain Observatory with the 13.7 meter telescope, extremely high velocity molecular outflows with total velocity width up to ～60 km·s–1 were detected for the first time in the two sub-regions, Spokes and Cone (C), of the NGC 2264 Cone. The detected outflow velocities were divided into three components (low, high and extremely high velocity) to reveal changes in the morphology and distribution of the molecular outflows. The 12CO emission of extremely high velocity shows multiple blueshifted and redshifted lobes. As the gas velocities increase, the distances between the lobes increase significantly, indicating an outward movement. The physical parameters of the outflows at different velocities in the Cone region were calculated, and the results showed that low velocity gas possesses the most energy and luminosity. The comparison of the total energy and luminosity of the outflow with the turbulent energy and luminosity of the molecular cloud suggests that the outflows may be a significant factor in influencing the turbulence in the Cone region.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： The Fe Low-ionization Broad Absorption Line Quasar (FeLoBALQ) is one of the rarest types of all quasars. Quasars blow out the surrounding violently, forming extreme outflows from which low ionized elements e.g. Fe provide the absorbing feature in FeLoBALQ spectra. Carrying high kinetic energy, the outflows of FeLoBALQ may possibly be enough for powering the $ M - \sigma_* $ relationship between the supermassive black hole mass $ M $ and the host-galaxy bulge velocity dispersion $ \sigma_* $. On the other hand, evidence has been found for the co-existence of FeLoBALQ with hosts' starburst or recent major merger. However, the FeLoBALQ sample collected so far is not large enough to stand for these theories statistically. This research focuses on digging out hidden FeLoBALQs from large quasar surveys, forming a FeLoBALQ catalog large enough for statistical and physical analyze. Adopting Convolutional Neural Network (CNN) method, 160 FeLoBALQs are newly identified from totally 50931 quasars in the SDSS (Sloan Digital Sky Survey) DR7Q (Data Release 7 Quasar catalog) in the redshift range of $ 0.8 < z < 2.125 $, with previous identified FeLoBALQ spectra as training sample. The FeLoBALQs' color are found redder than normal quasars, and previously identified FeLoBALQs are lightly redder than newly identified ones; these differences are more obvious on bluer end than on redder end, and nearly disappear in mid-infrared band. The proportion of FeLoBALQs out of all quasars given is $ 0.43\% $, higher than previous prediction, but may still be underestimated. Further researches may expand this method to larger samples e.g. SDSS DR16Q (Data Release 16 Quasar catalog) for larger FeLoBALQ sample, which may help to answer the questions of the relationship between FeLoBALQ and host galaxy star formation, FeLoBALQ and galaxy major merger, and the co-evolution of galaxies and central supermassive black holes.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： In order to solve the problem of low computational efficiency of thermal deformation of large reflector antennas, this paper proposes a method to quickly predict the thermal deformation of antennas. Firstly, the thermal analysis model of the single panel of the antenna is established. Then, the deformation law of the antenna is analyzed by numerical calculation under different temperature differences between the upper and lower surfaces of the panel, the back frame and the panel, the back frame and the environment. Finally, a linear regression relationship is fitted to realize the rapid calculation of the thermal deformation of the structure. The regression relationship is used to predict the deformation of the antenna structure. The predicted results are in good agreement with the simulated deformation results. At the same time, the linear relationship between temperature difference and thermal deformation is verified by experiment. This method is applied to the thermal deformation calculation of 110 m reflector antenna. The results show that the structural deformation under sunshine is mainly the deformation of the back frame.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： Track-Catalogue correlation is the precondition and foundation of large scale space object cataloging maintenance. The accuracy of correlation not only affects normal cataloging processing, but also affects the utilization of observation data and the effectiveness of space object surveillance system. In this paper, a method is put forward to improve the correlation accuracy of large-batch orbital track data. Firstly, based on the characteristics of orbit error propagation, a model is constructed to estimate the orbital prediction time error and to correct observation residual, aiming to transfer the large scale spatial error to a small scale time-domain error. Secondly, a correlation judgement model involving a four-parameter-joint feature vector is proposed, with threshold setting guidelines and a data correlation processing flow followed. Finally, some examples with regard to large-batch simulated and actual measured tracks are checked to illustrate the effectiveness of the method.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： The structural parameters of galaxies are the foundation for a deeper understanding of their formation and evolution. Existing galaxy fitting software has limitations such as slow running speed, heavy reliance on manual operation, and sensitivity to initial values. Based on the data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) survey, we constructed a training and testing dataset. The software GaLNet (Galaxy Light Profile Convolutional Neural Network), developed based on Convolutional Neural Networks (CNN), was applied to implement an algorithm for measuring galaxy structural parameters based on the Sérsic formula. By applying it to real HSC-SSP data and comparing it with the traditional method GALFIT, the average reduced chi-square value of the fitting results was reduced by 37%, and it has clear advantages in accuracy and running speed.
Subjects: Astronomy submitted time 2025-06-16 Cooperative journals: 《天文学报》
Abstract： In view of the current situation of inconsistent conclusions between existing asteroid impact monitoring systems, the linear approximation method used in the change line impact monitoring system was studied, and the conclusion that the deviation of the orbit distribution relative to the theoretical orbit distribution obtained by this method gradually became significant as the orbit propagation time increased. The impact probability of 6 asteroid instances was calculated using the Monte Carlo method. Compared with the results of the existing Monte Carlo impact monitoring system, the maximum difference is 2.1 times the standard deviation. The impact samples of asteroid 2020 VV in October 2056 are analyzed in detail, and the distribution of impact samples with time and space is depicted, and the conclusions are consistent with those of existing impact monitoring systems. As for the comparison between the different impact monitoring systems, it is concluded that the Monte Carlo impact monitoring system and the change line impact monitoring system currently have their own advantages and disadvantages: the former does not introduce the error caused by the linear approximation method, but the computational cost is high. The linear approximation method used in the latter will bring errors, but it can find some virtual impact sources with low impact probability that may be missed by the former, and the computational cost is relatively low.
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