With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unk...With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unknown.Therefore,by studying the formation and orbital transformation mechanism of satellites,planets and stars,the author puts forward a new theory on the formation and evolution of stars and galaxies,thus revealing the hierarchical structure of galaxies and the formation and evolution laws of main sequence stars,red giants,white dwarfs,black dwarfs,supernovae,neutron stars,black holes and quasars.Some special phenomena in the course of star formation and evolution,such as sunspots,flares,fast radio bursts and gamma-ray bursts,have also been revealed.展开更多
旋涡星系图像中所蕴含的旋臂信息,尤其是旋臂数量,对研究星系结构演化和星系动力学具有重要价值.在当前星系观测数据爆发式增长的背景下,如何快速识别出旋臂数量成为旋涡星系研究的重要问题.基于Galaxy Zoo DECaLS(Dark Energy Camera L...旋涡星系图像中所蕴含的旋臂信息,尤其是旋臂数量,对研究星系结构演化和星系动力学具有重要价值.在当前星系观测数据爆发式增长的背景下,如何快速识别出旋臂数量成为旋涡星系研究的重要问题.基于Galaxy Zoo DECaLS(Dark Energy Camera Legacy Survey)数据集,研究ResNet(Residual Networks)模型从旋涡星系图像中识别旋臂数量的方法,通过对比分析ResNet在不同网络层数下的实验结果,得出具有32层网络结构的ResNet模型,即ResNet32效果最佳,其总体准确率为83%,识别效果优于ViT(Vision Transformer)、EfficientNet和DenseNet等网络模型.在对不同旋臂数量的识别方面,识别准确率与训练样本的多少有较强的关系,拥有2个旋臂的图像数量有6800张,其F1分数(F1-Score)值达到0.9,而有4个旋臂的图像数量只有237张,其F1-Score值也最低.实验进一步分析了融合传统星系图像特征的识别效果,发现融合传统星系图像特征在提升旋臂数量识别方面作用有限.展开更多
The 11th data release of the LAMOST survey provides fundamental stellar parameters but lacks detailed abundance measurements forα-elements,which are crucial for understanding stellar populations and Galactic chemical...The 11th data release of the LAMOST survey provides fundamental stellar parameters but lacks detailed abundance measurements forα-elements,which are crucial for understanding stellar populations and Galactic chemical evolution.In this study,we derive the abundances of oxygen(O),magnesium(Mg),silicon(Si),calcium(Ca),and titanium(Ti)for over 6.8 million stars using LAMOST DR11 low-resolution spectra.To ensure reliable measurements,we select 760 open clusters spanning a broad range of ages and apply Monte Carlo sampling for accurate abundance estimates.Additionally,we utilize over 30,000 stars from the GALAH DR4 catalog to train an XGBoost model for extractingα-element abundances from LAMOST DR11 spectra.Bayesian linear regression is employed to analyze the compositional distribution across the Galactic disk and infer chemical gradients as a function of Galactocentric distance.Our results indicate a general increase in chemical abundances with Galactocentric distance,with oxygen showing the steepest gradient.Our results confirm the overall increase ofα-element abundances with Galactocentric distance,consistent with previous studies,while minor discrepancies in Mg,Ca,and Ti gradients likely arise from differences in sample selection,observational sensitivity,or Galactic enrichment processes.展开更多
[Objectives]To identify the authenticity of Longgu from the microscopic,infrared spectrum and chemical composition,and provide references for the quality control and evaluation methods of Longgu.[Methods]According to ...[Objectives]To identify the authenticity of Longgu from the microscopic,infrared spectrum and chemical composition,and provide references for the quality control and evaluation methods of Longgu.[Methods]According to the mineral characteristics of Longgu,the identification research was carried out by microscope observation,near-infrared spectroscopy and X-ray fluorescence spectrometer.By comparing the single polarizing and orthogonal polarizing characteristics of genuine and fake Longgu,a qualitative identification model of genuine Longgu was established based on the near-infrared spectrum of genuine Longgu,and the detection results of elements in Longgu were analyzed.[Results]The genuine Longgu had apatite optical properties,and was quite different from the fake Longgu of animal bones.Compared with modern animal bones,genuine Longgus had relatively less P and Ca,but they were enriched in elements Sr and F.The correlation coefficient model with good predictive ability can be established by using the near-infrared characteristic spectrum.[Conclusions]Polarizing microscope,near-infrared spectroscopy and X-ray fluorescence spectroscopy can improve the identification results of Longgu.展开更多
I examine images of 50 planetary nebulae(PNe)with observable post-common envelope evolution(CEE)binary central stars and find that jets are about 40%more common than dense equatorial outflows.Because,in some cases,ene...I examine images of 50 planetary nebulae(PNe)with observable post-common envelope evolution(CEE)binary central stars and find that jets are about 40%more common than dense equatorial outflows.Because,in some cases,energetic jets can compress an equatorial outflow and because fast jets might disperse early in the PN evolution and avoid detection,the CEE process is likelier to launch jets than to eject a dense equatorial outflow by a larger factor than 1.4.In most cases,the companion,mainly a main sequence star,launches the jets as it accretes mass from the envelope of the giant star.By CEE jets,I also refer to jets launched shortly before the onset of the CEE,likely a grazing envelope evolution phase,and shortly after the CEE.The jets and the accretion of mass by the companion before,during,and after the CEE affect envelope mass removal and the final orbital separation.Most numerical simulations of the CEE ignore jets,and those that include jets omit other processes.Despite the considerable progress in the last decade with tens of hydrodynamical simulations of the CEE,we are still far from correctly simulating the CEE.Including jets in simulations of the CEE requires heavy computer resources,but it must be the next step.展开更多
Atomic hydrogen(H I)gas,mostly residing in dark matter halos after cosmic reionization,is the fuel for star formation.Its relation to the properties of the host halo is the key to understand the cosmic H I distributio...Atomic hydrogen(H I)gas,mostly residing in dark matter halos after cosmic reionization,is the fuel for star formation.Its relation to the properties of the host halo is the key to understand the cosmic H I distribution and to mock H I large scale structure accurately and conveniently for the large area H I intensity mapping surveys in the future.In this work,we propose a flexible empirical model of H I±halo relation.In this model,while the H I mass depends primarily on the mass of host halo,there is also secondary dependence on other halo properties.We apply our model to the observation data of the Arecibo Fast Legacy ALFA(ALFALFA)survey,and find it can successfully fit the cosmic H I abundance(Ω_(H I)),average H I±halo mass relation<M_(H I)M_(h)>,and the H I clustering.The best fit of the ALFALFA data rejects the model with no secondary halo dependence of H I and the model with secondary dependence on the halo spin parameter(λ),and shows a strong dependence on halo formation time(a_(1/2))and halo concentration(c_(vir)).In an attempt to explain these findings from the perspective of hydrodynamical simulations,the IllustrisTNG simulation confirms the dependence of H I mass on secondary halo parameters.However,the IllustrisTNG results show a strong dependence onλand a weak dependence on cvirand a1/2,and also predict a much larger value of H I clustering on large scales than observations.This interesting difference between simulation and observation calls for improvements in understanding the H I±halo relation from both theoretical and observational sides.展开更多
We explore the feasibility of H I galaxy redshift surveys with the Five-hundred-meter Aperture Spherical Telescope(FAST) and its proposed Core Array interferometry.Using semi-analytical simulations,we compare the perf...We explore the feasibility of H I galaxy redshift surveys with the Five-hundred-meter Aperture Spherical Telescope(FAST) and its proposed Core Array interferometry.Using semi-analytical simulations,we compare the performance of the FAST single-dish and Core Array modes in drift scan (DS) and on-the-fly (OTF) observations across different redshifts.Our results show that the FAST single-dish mode enables significant H I detections at low redshifts (z■0.35) but is limited at higher redshifts due to shot noise.The Core Array interferometry,with higher sensitivity and angular resolution,provides robust H I galaxy detections up to z~1,maintaining a sufficient number density for power spectrum measurements and BAO constraints.At low redshifts (z~0.01–0.08),both configurations perform well,though cosmic variance dominates uncertainties.At higher redshifts (z>0.35),the Core Array outperforms the single-dish mode,while increasing the survey area has little impact on single-dish observations due to shot noise limitations.The DS mode efficiently covers large sky areas but is constrained by Earth’s rotation,whereas the OTF mode allows more flexible deep-field surveys at the cost of operational overhead.Our findings highlight the importance of optimizing survey strategies to maximize FAST’s potential for H I cosmology.The Core Array is particularly well-suited for high-redshift H I galaxy surveys,enabling precise constraints on large-scale structure and dark energy.展开更多
The subject is the mass of the three dominant, equilibrium cosmological objects: the irregular galaxy (dwarf), the regular galaxy (Hubble’s “tuning fork”), and the galactic cluster. The standard ΛCDM theory and a ...The subject is the mass of the three dominant, equilibrium cosmological objects: the irregular galaxy (dwarf), the regular galaxy (Hubble’s “tuning fork”), and the galactic cluster. The standard ΛCDM theory and a DEH offer contrasting views on the origin of these masses. The latter suggests that they are relics of the early universe.展开更多
本文首先回顾了“广义相对论”的时空观和引力透镜现象,修正了“光线弯曲的同频互扰解释”推导过程,然后提出了光线由光子传播、引力由引力子传播、光子与引力子基本不发生作用,由此导致的“引力弯曲光线”在微观机理上无法解释的问题...本文首先回顾了“广义相对论”的时空观和引力透镜现象,修正了“光线弯曲的同频互扰解释”推导过程,然后提出了光线由光子传播、引力由引力子传播、光子与引力子基本不发生作用,由此导致的“引力弯曲光线”在微观机理上无法解释的问题。最后列举了碰撞星系中的炙热气体与引力透镜反演的星系质量(暗物质)分布的分离现象的观测实例。传统的观点认为这些现象是暗物质存在的有力证据,本文认为:这些观测事实说明作为碰撞星系主要质量的不发光炙热气体,并未对引力透镜现象做出贡献,也就是说碰撞星系中的不发光炙热气体并未弯曲光线,也就没有弯曲它周围的时空,因此“广义相对论”中大质量物体引起其周围时空弯曲结论并不成立。本文认为碰撞星系中的暗物质是引力透镜中大质量发光星球发出的电磁波对可见光弯曲程度计算不足造成的,光线的弯曲与星球质量无关。This article first reviews the space-time view of “general relativity” and the phenomenon of gravitational lensing, corrects the derivation process of “the same-frequency mutual interference explanation of light bending”, and then proposes that light is propagated by photons, gravity is propagated by gravitons;photons and gravitons have basically no interaction, and the resulting “gravitational bending of light” is a problem that cannot be explained in terms of microscopic mechanisms. Finally, an observational example of the separation phenomenon between the hot gas in colliding galaxies and the galaxy mass (dark matter) distribution inverted by gravitational lensing is listed. The traditional view is that these phenomena are strong evidence for the existence of dark matter. This article believes that these observational facts show that the non-luminous hot gas, which is the main mass of the colliding galaxy, does not contribute to the gravitational lensing phenomenon. In other words, the non-luminous gas in the colliding galaxy does not contribute to the gravitational lensing phenomenon. Hot gas does not bend light, nor does it bend the space-time around it. Therefore, the conclusion in the “General Theory of Relativity” that massive objects cause the space-time around them to bend does not hold. This article believes that the dark matter in colliding galaxies is caused by insufficient calculation of the degree of bending of visible light by electromagnetic waves emitted by massive luminous stars in gravitational lenses. The bending of light has nothing to do with the mass of the planet.展开更多
文摘With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unknown.Therefore,by studying the formation and orbital transformation mechanism of satellites,planets and stars,the author puts forward a new theory on the formation and evolution of stars and galaxies,thus revealing the hierarchical structure of galaxies and the formation and evolution laws of main sequence stars,red giants,white dwarfs,black dwarfs,supernovae,neutron stars,black holes and quasars.Some special phenomena in the course of star formation and evolution,such as sunspots,flares,fast radio bursts and gamma-ray bursts,have also been revealed.
文摘旋涡星系图像中所蕴含的旋臂信息,尤其是旋臂数量,对研究星系结构演化和星系动力学具有重要价值.在当前星系观测数据爆发式增长的背景下,如何快速识别出旋臂数量成为旋涡星系研究的重要问题.基于Galaxy Zoo DECaLS(Dark Energy Camera Legacy Survey)数据集,研究ResNet(Residual Networks)模型从旋涡星系图像中识别旋臂数量的方法,通过对比分析ResNet在不同网络层数下的实验结果,得出具有32层网络结构的ResNet模型,即ResNet32效果最佳,其总体准确率为83%,识别效果优于ViT(Vision Transformer)、EfficientNet和DenseNet等网络模型.在对不同旋臂数量的识别方面,识别准确率与训练样本的多少有较强的关系,拥有2个旋臂的图像数量有6800张,其F1分数(F1-Score)值达到0.9,而有4个旋臂的图像数量只有237张,其F1-Score值也最低.实验进一步分析了融合传统星系图像特征的识别效果,发现融合传统星系图像特征在提升旋臂数量识别方面作用有限.
基金supported by the National Natural Science Foundation of China under program Nos.12090040,12090043,12473031,and 12003025as well as the Basic Research Program of Yunnan Province(No.202401AT070142)+2 种基金the International Center of Supernovae,Yunnan Key Laboratory(No.202302AN360001)the Natural Science Foundation of Yunnan Province(No.202201BC070003)the support of the Postdoctoral Fellowship Program of CPSF under grant Nos.GZC20240124 and 2024M760242.
文摘The 11th data release of the LAMOST survey provides fundamental stellar parameters but lacks detailed abundance measurements forα-elements,which are crucial for understanding stellar populations and Galactic chemical evolution.In this study,we derive the abundances of oxygen(O),magnesium(Mg),silicon(Si),calcium(Ca),and titanium(Ti)for over 6.8 million stars using LAMOST DR11 low-resolution spectra.To ensure reliable measurements,we select 760 open clusters spanning a broad range of ages and apply Monte Carlo sampling for accurate abundance estimates.Additionally,we utilize over 30,000 stars from the GALAH DR4 catalog to train an XGBoost model for extractingα-element abundances from LAMOST DR11 spectra.Bayesian linear regression is employed to analyze the compositional distribution across the Galactic disk and infer chemical gradients as a function of Galactocentric distance.Our results indicate a general increase in chemical abundances with Galactocentric distance,with oxygen showing the steepest gradient.Our results confirm the overall increase ofα-element abundances with Galactocentric distance,consistent with previous studies,while minor discrepancies in Mg,Ca,and Ti gradients likely arise from differences in sample selection,observational sensitivity,or Galactic enrichment processes.
基金Supported by the Subject Talent Research Promotion Program for"Xinglin Scholars"of Chengdu University of Traditional Chinese Medicine(ZRQN2020019).
文摘[Objectives]To identify the authenticity of Longgu from the microscopic,infrared spectrum and chemical composition,and provide references for the quality control and evaluation methods of Longgu.[Methods]According to the mineral characteristics of Longgu,the identification research was carried out by microscope observation,near-infrared spectroscopy and X-ray fluorescence spectrometer.By comparing the single polarizing and orthogonal polarizing characteristics of genuine and fake Longgu,a qualitative identification model of genuine Longgu was established based on the near-infrared spectrum of genuine Longgu,and the detection results of elements in Longgu were analyzed.[Results]The genuine Longgu had apatite optical properties,and was quite different from the fake Longgu of animal bones.Compared with modern animal bones,genuine Longgus had relatively less P and Ca,but they were enriched in elements Sr and F.The correlation coefficient model with good predictive ability can be established by using the near-infrared characteristic spectrum.[Conclusions]Polarizing microscope,near-infrared spectroscopy and X-ray fluorescence spectroscopy can improve the identification results of Longgu.
文摘I examine images of 50 planetary nebulae(PNe)with observable post-common envelope evolution(CEE)binary central stars and find that jets are about 40%more common than dense equatorial outflows.Because,in some cases,energetic jets can compress an equatorial outflow and because fast jets might disperse early in the PN evolution and avoid detection,the CEE process is likelier to launch jets than to eject a dense equatorial outflow by a larger factor than 1.4.In most cases,the companion,mainly a main sequence star,launches the jets as it accretes mass from the envelope of the giant star.By CEE jets,I also refer to jets launched shortly before the onset of the CEE,likely a grazing envelope evolution phase,and shortly after the CEE.The jets and the accretion of mass by the companion before,during,and after the CEE affect envelope mass removal and the final orbital separation.Most numerical simulations of the CEE ignore jets,and those that include jets omit other processes.Despite the considerable progress in the last decade with tens of hydrodynamical simulations of the CEE,we are still far from correctly simulating the CEE.Including jets in simulations of the CEE requires heavy computer resources,but it must be the next step.
基金supported by National SKA Program of China(grant Nos.2020SKA0110100,2020SKA0110401)National Key R&D Program of China(grant Nos.2018YFA0404502,2018YFA0404503)+1 种基金the National Natural Science Foundation of China(NSFC,grant Nos.11922305,11833005,11821303,and 12011530159)the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-A02。
文摘Atomic hydrogen(H I)gas,mostly residing in dark matter halos after cosmic reionization,is the fuel for star formation.Its relation to the properties of the host halo is the key to understand the cosmic H I distribution and to mock H I large scale structure accurately and conveniently for the large area H I intensity mapping surveys in the future.In this work,we propose a flexible empirical model of H I±halo relation.In this model,while the H I mass depends primarily on the mass of host halo,there is also secondary dependence on other halo properties.We apply our model to the observation data of the Arecibo Fast Legacy ALFA(ALFALFA)survey,and find it can successfully fit the cosmic H I abundance(Ω_(H I)),average H I±halo mass relation<M_(H I)M_(h)>,and the H I clustering.The best fit of the ALFALFA data rejects the model with no secondary halo dependence of H I and the model with secondary dependence on the halo spin parameter(λ),and shows a strong dependence on halo formation time(a_(1/2))and halo concentration(c_(vir)).In an attempt to explain these findings from the perspective of hydrodynamical simulations,the IllustrisTNG simulation confirms the dependence of H I mass on secondary halo parameters.However,the IllustrisTNG results show a strong dependence onλand a weak dependence on cvirand a1/2,and also predict a much larger value of H I clustering on large scales than observations.This interesting difference between simulation and observation calls for improvements in understanding the H I±halo relation from both theoretical and observational sides.
基金the support of the National SKA Program of China (Nos.2022SKA0110200 and 2022SKA0110203)the National Natural Science Foundation of China (NSFC,Nos.12473091 and 12473001),and 111 Project (No.B16009)the support of the Fundamental Research Funds for the Central Universities (No.N2405008)。
文摘We explore the feasibility of H I galaxy redshift surveys with the Five-hundred-meter Aperture Spherical Telescope(FAST) and its proposed Core Array interferometry.Using semi-analytical simulations,we compare the performance of the FAST single-dish and Core Array modes in drift scan (DS) and on-the-fly (OTF) observations across different redshifts.Our results show that the FAST single-dish mode enables significant H I detections at low redshifts (z■0.35) but is limited at higher redshifts due to shot noise.The Core Array interferometry,with higher sensitivity and angular resolution,provides robust H I galaxy detections up to z~1,maintaining a sufficient number density for power spectrum measurements and BAO constraints.At low redshifts (z~0.01–0.08),both configurations perform well,though cosmic variance dominates uncertainties.At higher redshifts (z>0.35),the Core Array outperforms the single-dish mode,while increasing the survey area has little impact on single-dish observations due to shot noise limitations.The DS mode efficiently covers large sky areas but is constrained by Earth’s rotation,whereas the OTF mode allows more flexible deep-field surveys at the cost of operational overhead.Our findings highlight the importance of optimizing survey strategies to maximize FAST’s potential for H I cosmology.The Core Array is particularly well-suited for high-redshift H I galaxy surveys,enabling precise constraints on large-scale structure and dark energy.
文摘The subject is the mass of the three dominant, equilibrium cosmological objects: the irregular galaxy (dwarf), the regular galaxy (Hubble’s “tuning fork”), and the galactic cluster. The standard ΛCDM theory and a DEH offer contrasting views on the origin of these masses. The latter suggests that they are relics of the early universe.
文摘本文首先回顾了“广义相对论”的时空观和引力透镜现象,修正了“光线弯曲的同频互扰解释”推导过程,然后提出了光线由光子传播、引力由引力子传播、光子与引力子基本不发生作用,由此导致的“引力弯曲光线”在微观机理上无法解释的问题。最后列举了碰撞星系中的炙热气体与引力透镜反演的星系质量(暗物质)分布的分离现象的观测实例。传统的观点认为这些现象是暗物质存在的有力证据,本文认为:这些观测事实说明作为碰撞星系主要质量的不发光炙热气体,并未对引力透镜现象做出贡献,也就是说碰撞星系中的不发光炙热气体并未弯曲光线,也就没有弯曲它周围的时空,因此“广义相对论”中大质量物体引起其周围时空弯曲结论并不成立。本文认为碰撞星系中的暗物质是引力透镜中大质量发光星球发出的电磁波对可见光弯曲程度计算不足造成的,光线的弯曲与星球质量无关。This article first reviews the space-time view of “general relativity” and the phenomenon of gravitational lensing, corrects the derivation process of “the same-frequency mutual interference explanation of light bending”, and then proposes that light is propagated by photons, gravity is propagated by gravitons;photons and gravitons have basically no interaction, and the resulting “gravitational bending of light” is a problem that cannot be explained in terms of microscopic mechanisms. Finally, an observational example of the separation phenomenon between the hot gas in colliding galaxies and the galaxy mass (dark matter) distribution inverted by gravitational lensing is listed. The traditional view is that these phenomena are strong evidence for the existence of dark matter. This article believes that these observational facts show that the non-luminous hot gas, which is the main mass of the colliding galaxy, does not contribute to the gravitational lensing phenomenon. In other words, the non-luminous gas in the colliding galaxy does not contribute to the gravitational lensing phenomenon. Hot gas does not bend light, nor does it bend the space-time around it. Therefore, the conclusion in the “General Theory of Relativity” that massive objects cause the space-time around them to bend does not hold. This article believes that the dark matter in colliding galaxies is caused by insufficient calculation of the degree of bending of visible light by electromagnetic waves emitted by massive luminous stars in gravitational lenses. The bending of light has nothing to do with the mass of the planet.
