检索结果-内蒙古大学图书馆

arXiv 2024年

作者： Ji, Rui-Jie Meng, Xiang-Cun Liu, Zheng-Wei Yunnan Observatories Chinese Academy of Sciences Kunming 650216 Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Yunnan Key Laboratory Kunming650216 China

The origin of intermediate helium (He)-rich hot subdwarfs are still unclear. Previous studies have suggested that some surviving Type Ia supernovae (SNe Ia) companions from the white dwarf + main-sequence (WD+MS) channel may contribute to the intermediate He-rich hot subdwarfs. However, previous studies ignored the impact of atomic diffusion on the post-explosion evolution of surviving companion stars of SNe Ia, leading to that they could not explain the observed surface He abundance of intermediate He-rich hot subdwarfs. In this work, by taking the atomic diffusion and stellar wind into account, we trace the surviving companions of SNe Ia from the WD+MS channel using the one-dimensional stellar evolution code MESA until they evolve into hot subdwarfs. We find that the surface He-abundances of our surviving companion models during their core He-burning phases are in a range of −1 log(NHe/NH) 0, which are consistent with those observed in intermediate He-rich hot subdwarfs. This seems to further support that surviving companions of SNe Ia in the WD+MS channel are possible to form some intermediate He-rich hot subdwarfs. Copyright © 2024, The Authors. All rights reserved.

关键词： Helium

来源：评论

学校读者我要写书评

暂无评论

Compact objects in close orbits as gravitational wave sources: Formation scenarios and properties

引用

Results in Physics 2024年 59卷

作者： Li, Zhenwei Chen, Xuefei Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Science Kunming 650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming 650216 China

Gravitational Waves (GWs) provide a unique way to explore our Universe. The ongoing ground-based detectors, e.g., LIGO, Virgo, and KAGRA, and the upcoming next-generation detectors, e.g., Cosmic Explorer and Einstein Telescope, as well as the future space-borne GW antennas, e.g., LISA, TianQin, and TaiJi, cover a wide range of GW frequencies from ∼10⁻⁴Hz to ∼10³Hz and almost all types of compact objects in close orbits serve as the potential target sources for these GW detectors. The synergistic multi-band GW and EM observations would allow us to study fundamental physics from stars to cosmology. The formation of stellar GW sources has been extensively explored in recent years, and progress on physical processes in binary interaction has been made as well. Furthermore, some studies have shown that the progress in binary evolution may significantly affect the properties of the stellar GW sources. In this article, we review the formation channels of compact objects in close orbits and discuss their implications for GW observations. © 2024 The Author(s)

关键词： Binary black holes Binary evolution Binary neutron stars Double white dwarfs Gravitational wave

来源：评论

学校读者我要写书评

暂无评论

Revisiting the X-ray emission of the asynchronous polar V1432 Aql

引用

Research in Astronomy and Astrophysics 2021年第12期21卷 499-508页

作者： Qi-Shan Wang Sheng-Bang Qian Li-Ying Zhu Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China

As the only eclipsing asynchronous polar,V1432 Aql provides an excellent laboratory to study the interaction between the accreted matter and the magnetic ***,we report an analysis of the X-ray data from the contemporaneous NuSTAR and Swift-XRT *** X-ray data present a profile with a low-intensity state for almost half an orbital period,a dip at 0.6 phase,and a peak at 0.75 phase,which suggests that there was only one accretion region during the observation and the claim is supported by the spectral *** comparison with the previous data indicates that the X-ray data have an orbital modulation,as the case in BeppoSAX,rather than a spin one observed in *** attribute the orbit and spin modulations to the different accretion geometries at *** spectral analysis of the wide-band data presents a significant reflection effect,a commonly observed soft X-ray temperature,and the energy balance in V1432 ***,we obtained a low total accretion rate of 1.3×10~(-10)M yr~(-1)and a high specific accretion rate of 3.8 g cm~(-2)s~(-1)which explains the strong reflection from the surface of the white ***,due to its complex emission,a more physical understanding of its accretion geometry is still outstanding.

关键词： stars:individual(V1432 Aql) cataclysmic variables:asynchronous polars

来源：评论

学校读者我要写书评

暂无评论

The deep and low-mass-ratio contact binary CSS J022914.4+044340 with a luminous additional companion

引用

Research in Astronomy and Astrophysics 2021年第7期21卷 254-260页

作者： Liang Liu Xu-Zhi Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The first B-,V-,R_c-and I_c-band light curves of CSS J022914.4+044340 are presented and *** is found that CSS J022914.4+044340 is a low mass ratio(0.198 ± 0.005) deep(63.7 ± 7.9 %)contact binary,indicating that it is already at the end evolutionary stage of tidally-locked evolution via magnetized *** of the totally eclipsing character,the photometric solutions are *** temperature and metallicity are determined from the spectroscopic data as T=5855 ± 15 K and[Fe/H]=-0.842 ± 0.031,*** on the parallax of Gaia EDR3,the physical parameters of CSS J022914.4+044340 are estimated as M_(1)=1.44_(-0.22)^(+0.25) M_⊙,M_(2)=0.29_(-0.05)^(0.05) M_⊙,R_(1)=1.26_(-0.06)^(0.08) R_⊙,R2=0.65_(-0.04)^(0.03) R_⊙,L_(1)=1.718_(0.191)^(0.186) L_⊙ and L_(2)=0.416_(-0.050)^(0.039) L_⊙.Combining the fraction of light from the third body via the photometric solution(54%),the luminosity of the third body is estimated as 2.705 L_⊙.The third body may be inferred to be a ***,why the primary component of CSS J022914.4+044340 has higher mass compared to similar systems is explained,as well as why its metallicity is so poor.

关键词： binaries:eclipsing binaries:close stars:individuals(CSS J022914.4+044340) stars:evolution

来源：评论

学校读者我要写书评

暂无评论

Orbital period correction and light curve modeling of the W-subtype shallow contact binary OW Leo

引用

Research in Astronomy and Astrophysics 2021年第2期21卷 24-30页

作者： Xiao Zhou Sheng-Bang Qian Yunnan Observatories Chinese Academy of Sciences(CAS)Kunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of the Chinese Academy of Sciences Beijing 100049China

Orbital period and multi-color light curves’investigation of OW Leo are presented for the first *** orbital period of OW Leo is corrected from P=0.325545 days to P=0.32554052 days in our work,and the observational data from the All-Sky Automated Survey for Super Novae(ASAS-SN)are used to test the newly determined orbital ***,the phased light curves are calculated with the new period and the Wilson-Devinney program is applied to model the light curves,which reveal that OW Leo is a W-subtype shallow contact binary system(q=3.05,f=12.8%).The absolute physical parameters of the two component stars are estimated to be M_(1)=0.31(1)M_(⊙),M_(2)=0.95(3)M_(⊙),R_(1)=0.63(1)R⊙,R_(2)=1.04(1)R_(⊙),L_(1)=0.43(1)L_(⊙)and L_(2)=1.01(2)L_(⊙).The evolutionary status shows that the more massive star is less evolved than the less massive *** Leo has very low metal abundance,which means its formation and evolution are hardly influenced by any additional *** is formed from an initially detached binary system through nuclear evolution and angular momentum loss via magnetic braking,and has passed a very long time of main sequence evolution.

关键词： techniques photometric-binaries eclipsing-stars evolution

来源：评论

学校读者我要写书评

暂无评论

Unveiling the Nature of Gravitational-Wave Emission in Core-collapse Supernovae with Perturbative Analysis

arXiv

引用

arXiv 2024年

作者： Zha, Shuai Andersen, Oliver Eggenberger O’Connor, Evan P. Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-106 91 Sweden

Gravitational waves (GWs) can provide crucial information about the central engines of core-collapse supernovae (CCSNe). In order to unveil the nature of GW emission in CCSNe, we apply perturbative analyses with the same underlying equations as simulations to diagnose oscillations of the proto-neutron star (PNS) during ∼1 s postbounce. In the pseudo-Newtonian case, we find that radial profiles of GW emission match well between the perturbative analysis with l = 2 and simulations inside the PNS at any frequency and time. This confirms that the GW emission of CCSNe arises from the global PNS oscillations in the perturbative regime. Based on this, we solve for the discrete eigenmodes with a free PNS surface and tentatively identify a set of g modes and the f mode contributing to the peak GW emission. We also offer a possible explanation for the power gap in the GW spectrum found in simulations that lies at the frequency with vanishing cumulative emission of the PNS. Our results enhance the predictive power of perturbative analyses in the GW signals of CCSNe. Copyright © 2024, The Authors. All rights reserved.

关键词： Gravity waves

来源：评论

学校读者我要写书评

暂无评论

Progress of the Study on (Sub)millimeter Lines in Galaxies During the Herschel Period

引用

Chinese Astronomy and Astrophysics 2022年第1期46卷 1-35页

作者： Pei-bin, Chen Jia-min, Liu Ying-he, Zhao Yunnan Astronomical Observatories Chinese Academy of Sciences Kunming 650011 China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Structure and Evolution of Celestial Bodies Chinese Academy of Sciences Kunming 650011 China

After the advent of Herschel Space Observatory, there is much progress of the observational studies on the (sub)millimeter ((sub)mm) lines, such as the middle to high-J CO rotational transitions (J = 4–10), multiple H₂O lines, and fine-structure emissions of atoms (e.g., C, O) and ions (e.g., C⁺, N⁺). These lines are important coolants for the interstellar medium (ISM), and thus can be used to investigate the physical conditions and chemical compositions of the ISM, as well as their power sources. In this paper, we first introduce how to investigate the star formation properties (such as the calibration of star formation rate (SFR) and the determination of star formation mode) using different (sub)mm lines. Then we review for the different methods of measuring total molecular mass, and discuss their advantages and caveats. At last we summarize the use of CO (CO spectral line energy distribution (CO SLED) and the ratio of mid-J CO lines to far-infrared continuum) and other lines to diagnose the power source in galaxies. © 2022

关键词： (sub)millimeter lines Galaxy formation and evolution ISM Molecular gas Star formation

来源：评论

学校读者我要写书评

暂无评论

Resolution enhancement of SOHO/MDI Magnetograms

arXiv

引用

arXiv 2024年

作者： Qin, Ying Ji, Kai-Fan Liu, Hui Yu, Xiao-Guang Yunan Observatories Chinese Academy of Sciences Yunan Kunming650011 China University of Chinese Academy of Sciences Beijing100049 China Yunnan Key Laboratory of Solar Physics and Space Science 650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement frequency. The augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field variation. Within the realm of astronomical data processing, super-resolution reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution and high-resolution images, thereby achieving higher-resolution astronomical images. This paper is an application study in high-dimensional non-linear regression. Deep learning models were employed to perform super-resolution (SR) modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms, thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed information. For this study, a dataset comprising 9,717 pairs of data from April 2010 to February 2011 was used as the training set, 1,332 pairs from March 2011 were used as the validation set, and 1,034 pairs from April 2011 were used as the test set. After data preprocessing, we randomly cropped 128x128 sub-images as the low resolution (LR) from the full-disk MDI magnetograms, and the corresponding 512x512 sub-images as high resolution (HR) from the HMI full-disk magnetograms for model training. The tests conducted have shown that the study successfully produced reliable 4x super-resolution reconstruction of full-disk MDI magnetograms. The MESR model’s results (0.911) were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient values. Furthermore, the method achieved the best PSNR, SSIM, MAE and RMSE values, indicating that the MESR model can effectively reconstruct magnetog. © 2024, CC BY-NC-SA.

关键词： Image enhancement

来源：评论

学校读者我要写书评

暂无评论

Spectral properties of the neutron star low-mass X-ray binary 4U 1636–53, XTE J1739–285 and MAXI J1816–195

arXiv

引用

arXiv 2025年

作者： Fei, Zhenyan Lyu, Ming Zhang, Guobao Yang, Xuejuan García, Federico Department of Physics Xiangtan University Hunan Xiangtan411105 China Key Laboratory of Stars and Interstellar Medium Xiangtan University Hunan Xiangtan411105 China Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China C.C.5 Villa Elisa1894 Argentina

We investigated simultaneous NICER plus NuSTAR observations of three neutron star low-mass X-ray binary 4U 1636–53, XTE J1739–285 and MAXI J1816–195 using the latest reflection models, with the seed photons feeding into the corona originating from either the neutron star (NS) or the accretion disk. We found that, for the sources in the hard spectral state, more than ∼ 50% of the NS photons enter into the corona if NS provides seed photons, while only ∼ 3%-5% disk photons go to the corona if seed photons come from the disk. This finding, together with the derived small height of the corona, favors the lamp-post geometry or boundary layer scenario where the corona is close to the central neutron star. Additionally, we found that the source of the seed photons has big influence in the significance of the NS radiation, especially for the soft spectral state. This result may help explain why the NS radiation in MAXI J1816–195 is weak in the previous work. More importantly, for the first time, we explored the properties of the corona in the NS systems with the compactness (l − θ) diagram. We found that the corona in the NS systems all lie in the left side of the pair-production forbidden region, away from the predicted pair-production lines. This finding indicates that either the corona in these NS systems is not pair-dominated, possibly due to the additional cooling from NS photons, or the corona is composed of both thermal and non-thermal electrons. Copyright © 2025, The Authors. All rights reserved.

关键词： Photons

来源：评论

学校读者我要写书评

暂无评论

Chapter 3 Extra-galactic gamma-ray sources

引用

Chinese Physics C 2022年第3期46卷 63-84页

作者： Xiang-Yu Wang Xiao-Jun Bi Zhen Cao Piero Vallania Han-Rong Wu Da-Hai Yan Qiang Yuan School of Astronomy and Space Sciences Nanjing UniversityNanjing 210093China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China INAF-Osservatorio Astrofisico di Torino Strada Osservatorio 2010025 Pino Torinese(TO)Italy and INFN Sezione di TorinoVia P.Giuria 110125 TorinoItaly Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan ObservatoriesChinese Academy of SciencesKunming 650011China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China

Extra-galactic gammaray sources,such as gamma-ray bursts,active galactic nuclei,starburst galaxies,are interesting and important targets for LHAASO *** this chapter,the prospects of detecting these sources with LHAASO and their physical implications are *** upgrade plan for the Water Cherenkov Detector Array(WCDA),which aims to enhance the detectability of relatively lower energy photons,is also *** addition,a study on constraining the extragalactic background light with LHAASO observation of blazars is presented.

关键词： AGN Gamma-rays GRBs

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：