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arXiv 2025年

作者： Peng, Jing-Qiang Zhang, Shu Shui, Qing-Cang Zhang, Shuang-Nan Kong, Ling-Da Chen, Yu-Peng Wang, Peng-Ju Ji, Long Qu, Jin-Lu Tao, Lian Ge, Ming-Yu Chang, Zhi Li, Jian Li, Zhao-Sheng Yu, Zhuo-Li Yan, Zhe Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Institute für Astronomie und Astrophysik Kepler Center for Astro and Particle Physics Eberhard Karls Universität Sand 1 TübingenD-72076 Germany School of Physics and Astronomy Sun Yat-Sen University Zhuhai519082 China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei230026 China Key Laboratory of Stars and Interstellar Medium Xiangtan University Hunan Xiangtan411105 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China

Swift J1727.8–1613 is a black hole X-ray binary newly discovered in 2023. We perform spectral analysis with simultaneous Insight-HXMT, NICER and NuSTAR observations when the source was approaching to the hard intermediate state. Such a joint view reveals an additional hard component apart from the normally observed hard component with reflection in the spectrum, to be distinguished from the usual black hole X-ray binary systems. By including this extra component in the spectrum, we have measured a high spin of 0.98+0.02−0.07 and an inclination of around 40+1.2−0.8 degrees, which is consistent with NICER results reported before. However, we find that the additional spectral component can not be exclusively determined due to the model degeneracy. Accordingly, a possible jet/corona configuration is adjusted to account for the spectral fitting with different model trials. The extra component may originate either from a relativistic jet or a jet base/corona underneath a slow jet. Copyright © 2025, The Authors. All rights reserved.

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Detectability of neutrino-signal fluctuations induced by the hadron-quark phase transition in failing core-collapse supernovae

arXiv

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arXiv 2022年

作者： Lin, Zidu Zha, Shuai O'Connor, Evan P. Steiner, Andrew W. Department of Physics and Astronomy University of Tennessee Knoxville Knoxville37996 United States Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai200240 China 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 Physics Division Oak Ridge National Laboratory Oak Ridge37831 United States

We introduce a systematic and quantitative methodology for establishing the presence of neutrino oscillatory signals due to the hadron-quark phase transition (PT) in failing core-collapse supernovae from the observed neutrino event rate in water- or ice-based neutrino detectors. The methodology uses a likelihood ratio in the frequency domain as a test-statistic;it is employed for quantitative analysis of neutrino signals without assuming the frequency, amplitude, starting time, and duration of the PT-induced oscillations present in the neutrino events and thus it is suitable for analyzing neutrino signals from a wide variety of numerical simulations. We test the validity of this method by using a core-collapse simulation of a 17 solar-mass star by Zha et al. (2021) [1]. Based on this model, we further report the presence of a PT-induced oscillations quantitatively for a core-collapse supernovae out to a distance of ∼ 10 kpc, ∼ 5 kpc for IceCube and to a distance of ∼ 10 kpc, ∼ 5 kpc and ∼ 1 kpc for a 0.4 Mt mass water Cherenkov detector. This methodology will aid the investigation of a future galactic supernova and the study of hadron-quark phase in the core of core-collapse supernovae. Copyright © 2022, The Authors. All rights reserved.

关键词： Hadrons

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WASP-35 and HAT-P-30/WASP-51: re-analysis using TESS and ground-based transit photometry

arXiv

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arXiv 2022年

作者： Bai, Lu Gu, Shenghong Wang, Xiaobin Sun, Leilei Kwok, Chi-Tai Hui, Ho-Keung Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China Ho Koon Nature Education cum Astronomical Centre Sik Sik Yuen China

High-precision transit observations provide excellent opportunities for characterizing the physical properties of exoplanetary systems. These physical properties supply many pieces of information for unvealing the internal structure, external atmosphere, and dynamical history of the planets. We present revised properties of transiting systems WASP-35 and HAT-P-30/WASP-51 through analyzing newly available TESS photometry and ground-based observations obtained at 1m telescope of Yunnan Observatories as well as from the literature. The improved system parameters are consistent with the previous results. Furthermore, we find that HAT-P-30b/WASP-51b’s transits show significant timing variation which cannot be explained by decaying orbit due to tidal dissipation and the Rømer effect, while both apsidal precession and an additional perturbing body could reproduce this signal through our comprehensive dynamical simulations. Because both of them are valuable targets which are suitable for transmission spectroscopy, we make some predictions for atmospheric properties of WASP-35b and HAT-P-30b/WASP-51b based on newly derived system parameters. Copyright © 2022, The Authors. All rights reserved.

关键词： Monte Carlo methods

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Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 4151 during Outburst Stage. II. Four Season Observation Results

arXiv

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arXiv 2024年

作者： Feng, Hai-Cheng Li, Sha-Sha Bai, J.M. Liu, H.T. Lu, Kai-Xing Pang, Yu-Xuan Sun, Mouyuan Wang, Jian-Guo Zhang, Yang-Wei Zhou, Shuying Yunnan Observatories Chinese Academy of Sciences Yunnan Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Yunnan Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100101 China Department of Astronomy School of Physic Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy Xiamen University Fujian Xiamen361005 China South-Western Institute for Astronomy Research Yunnan University Kunming650500 China

We present the results of a four-year velocity-resolved reverberation mapping (RM) campaign of the changing-look active galactic nucleus (CL-AGN) NGC 4151 during its outburst phase. By measuring the time lags of the Hα, Hβ, Hγ, He I, and He II emission lines, we confirm a stratified broad-line region (BLR) structure that aligns with predictions from photoionization models. Intriguingly, we observed an "anti-breathing" phenomenon, where the lags of broad emission lines decreased with increasing luminosity, contrary to the typical expectation. This anomaly may be attributed to the influence of the ultraviolet-optical lag or non-virialized motions in the BLR gas. Velocity-resolved RM and ionization mapping analyses revealed rapid and significant changes in the BLR geometry and kinematics on timescales within one year, which cannot be interpreted by any single mechanism, such as an inhomogeneous BLR, variations in radiation pressure, or changes in the illuminated ionizing field. Additionally, the Hβ lags of NGC 4151 and other CL-AGNs agree with the radius-luminosity relationship established for AGNs with low accretion rates, implying that the CL phenomenon is more likely driven by intrinsic changes in the accretion rate rather than obscuration. These findings provide new insights into the complex internal processes of CL-AGNs and highlight the importance of long-term, multi-line RM for understanding BLR structures, geometry, and kinematics. © 2024, CC BY.

关键词： Active Galactic Nuclei

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VLBI Astrometry of Radio Stars to Link Radio and Optical celestial Reference Frames. I. HD 199178 & AR Lacertae

arXiv

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arXiv 2023年

作者： Chen, Wen Zhang, Bo Zhang, Jingdong Yang, Jun Xu, Shuangjing Sun, Yan Mai, Xiaofeng Shu, Fengchun Wang, Min Yunnan Observatories Chinese Academy of Sciences Yunnan Kunming650216 China Yuquan Road Shijingshan District Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai China Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-439 92 Sweden Korea Astronomy and Space Science Institute 776 Daedeok-daero Yuseong-gu Daejeon34055 Korea Republic of Yunnan Key Laboratory of the Solar Physics and Space Science Kunming650216 China

To accurately link the radio and optical celestial Reference Frames (CRFs) at optical bright end, i.e., with Gaia G band magnitude 13, increasing number and improving sky distribution of radio stars with accurate astrometric parameters from both Very Long Baseline Interferometry (VLBI) and Gaia measurements are mandatory. We selected two radio stars HD 199178 and AR Lacertae as the target for a pilot program for the frame link, using the Very Long Baseline Array (VLBA) at 15 GHz at six epochs spanning about 1 year, to measure their astrometric parameters. The measured parallax of HD 199178 is 8.949 ± 0.059 mas and the proper motion is μα cos δ = 26.393 ± 0.093, μδ = −0.950 ± 0.083 mas yr−1, while the parallax of AR Lac is 23.459 ± 0.094 mas and the proper motion is μα cos δ = −51.906 ± 0.138, μδ = 46.732 ± 0.131 mas yr−1. Our VLBI measured astrometric parameters have accuracies about 4-5 times better than the corresponding historic VLBI measurements and comparable accuracies with those from Gaia, validating the feasibility of frame link using radio stars. With the updated astrometric parameters for these two stars, there is a ∼ 25% reduction of the uncertainties on the Y axis for both orientation and spin parameters. Copyright © 2023, The Authors. All rights reserved.

关键词： Stars

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New simulations of the X-ray spectra and polarizations of accretion-disc corona systems with various geometrical configurations I. Model Description

arXiv

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arXiv 2022年

作者： Yang, Xiao-Lin Wang, Jian-Cheng Yang, Chu-Yuan Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China University of Chinese Academy of Sciences Beijing100049 China

Energetic X-ray radiations emitted from various accretion systems are widely considered to be produced by Comptonization in the hot corona. The corona and its interaction with the disc play an essential role in the evolution of the system and are potentially responsible for many observed features. However many intrinsic properties of the corona are still poorly understood, especially for the geometrical configurations. The traditional spectral fitting method is not powerful enough to distinguish various configurations. In this paper we intent to investigate the possible configurations by modeling the polarization properties of X-ray radiations. The geometries of the corona include the slab, sphere and cylinder. The simulations are implemented through the publicly available code, LEMON, which can deal with the polarized radiative transfer and different electron distributions readily. The results demonstrate clearly that the observed polarizations are dependent on the geometry of the corona heavily. The slab-like corona produces the highest polarization degrees, the following are the cylinder and sphere. One of the interesting things is that the polarization degrees first increase gradually and then decrease with the increase of photon energy. For slab geometry there exists a zero point where the polarization vanishes and the polarization angle rotates for 90◦. These results may potentially be verified by the upcoming missions for polarized X-ray observations, such as IXP E and eXT P . © 2022, CC BY.

关键词： Polarization

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NICER, NuSTAR and Insight-HXMT views to black hole X-ray binary SLX 1746–331

arXiv

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arXiv 2025年

We study the spectral and temporal properties of the black hole X-ray transient binary SLX 1746–331 during the 2023 outburst with NICER, NuSTAR, and Insight-HXMT observations. Through the joint fitting of the spectra from NICER, NuSTAR, and Insight-HXMT, the spin and inclination angles are measured for the first time as 0.85 ± 0.03 and 53 ± 0.5°, respectively. Accordingly, the mass of the compact star is updated from the previous lower limit of 3.3±2.1M☉ to 5.5 ± 3.6M☉, which is consistent with 5.2 ± 4.5M☉ measured with an empirical mass-luminosity correlation of BH samples. With more NICER observations covering the later decay of the outburst, we confirm that the entire outburst was dominated by the disk emissions, and the thermal spectrum follows F ∝ Tin3.974±0.003, till a luminosity of over than two magnitudes lower than the maximum of the outburst. Copyright © 2025, The Authors. All rights reserved.

关键词： Black holes

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Asteroseismological analysis of the non-Blazhko RRab star EPIC 248846335 in LAMOST - Kepler/ K2 project

arXiv

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arXiv 2024年

作者： Zong, Peng Fu, Jian-Ning Su, Jie Hu, Xueying Zhang, Bo Wang, Jiaxin Liu, Gao-Chao Meng, Gang Catanzaro, Gianni Frasca, Antonio Wang, Haotian Zong, Weikai Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Department of Astronomy Beijing Normal University Beijing100875 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China National Astronomical Observatories of China Chinese Academy of Science Beijing100012 China College of Science Chongqing University of Posts and Telecommunications Chongqing400065 China Center for Astronomy and Space Sciences China Three Gorges University Yichang443002 China INAF - Osservatorio Astrofisico di Catania Via S.Sofia 78 CataniaI-95123 Italy

We conduct an asteroseismological analysis on the non-Blazhko ab-type RR Lyrae star EPIC 248846335 employing the Radial Stellar Pulsations (RSP) module of the Modules for Experiments in Stellar Astrophysics (MESA) based on the set of stellar parameters. The atmospheric parameters as Teff = 6933±70 K, log g = 3.35± 0.50 and [Fe/H] = -1.18 ± 0.14 are estimated from the Low-Resolution Spectra of LAMOST DR9. The luminosity L = 49.70+2.99−1.80 L and mass M = 0.56 ± 0.07 M are calculated, respectively, using the distance provided by Gaia and the metallicity estimated from the Low-Resolution Spectra. The Fourier parameters of the light curves observed by K2 and RV curves determined from the Medium-Resolution Spectra of LAMOST DR10 are also calculated in this work. The period of the fundamental mode of the star and the residuals r of the Fourier parameters between the models and observations serve to select optimal model, whose stellar parameters are Teff = 6700 ± 220 K, log g = 2.70, [Fe/H] = -1.20 ± 0.2, M = 0.59 ± 0.05 M, and L = 56.0 ± 4.2 L. The projection factors are constrained as 1.20 ± 0.02 and 1.59 ± 0.13 by the blue- and red-arm observed velocities with their corresponding RV curves derived from the best-fit model, respectively. The precise determination of stellar parameters in ab-type RR Lyrae stars is crucial for understanding the physical processes that occur during pulsation and for providing a deeper understanding of its Period-Luminosity relationship. © 2024, CC BY-NC-SA.

关键词： Stars

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The Dusty and Extremely Red Progenitor of the Type II Supernova 2023ixf in Messier 101

arXiv

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arXiv 2023年

作者： Xiang, Danfeng Mo, Jun Wang, Lingzhi Wang, Xiaofeng Zhang, Jujia Lin, Han Wang, Lifan Department of Physics Tsinghua Center for Astrophysics Tsinghua University Haidian District Beijing100084 China South America Center for Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Beijing Planetarium Beijing Academy of Sciences and Technology Beijing100044 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China Mitchell Institute for Fundamental Physics and Astronomy Texas A&M University College StationTX77843 United States

Stars with initial masses in the range of 8–25 solar masses are thought to end their lives as hydrogen-rich supernovae (SNe II). Based on the pre-explosion images of Hubble Space Telescope (HST) and Spitzer Space Telescope, we place tight constraints on the progenitor candidate of type IIP SN 2023ixf in Messier 101. Fitting of the spectral energy distribution (SED) of its progenitor with dusty stellar spectral models results in an estimation of the effective temperature as 3091+−422258 K. The luminosity is estimated as log(L/L)∼ 4.83, consistent with a red supergiant (RSG) star with an initial mass of 12+−21 M. The derived mass loss rate (6–9×10−6 M yr−1) is much lower than that inferred from the flash spectroscopy of the SN, suggesting that the progenitor experienced a sudden increase in mass loss when approaching the final explosion. In the infrared bands, significant deviation from the range of regular RSGs in the color-magnitude diagram and period-luminosity space of the progenitor star indicates enhanced mass loss and dust formation. Combining with new evidence of polarization at the early phases of SN 2023ixf, such a violent mass loss is likely a result of binary interaction. Copyright © 2023, The Authors. All rights reserved.

关键词： Luminance

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Fan beamed X-ray emission from 1 keV to above 130 keV from the ultraluminous X-ray pulsar RX J0209.6−7427 in the Small Magellanic Cloud

arXiv

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arXiv 2022年

作者： Hou, Xian Ge, M.Y. Ji, L. Zhang, S.N. You, Y. Tao, L. Zhang, S. Soria, R. Feng, H. Zhou, M. Tuo, Y.L. Song, L.M. Wang, J.C. Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China School of Physics and Astronomy Sun Yat-Sen University Zhuhai519082 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Department of Astronomy Tsinghua University Beijing100084 China

We present detailed timing and spectral analyses of the transient X-ray pulsar RX J0209.6−7427 in the Small Magellanic Cloud during its 2019 giant outburst. With a better known distance than most galactic X-ray pulsars, its peak luminosity is determined to be (1.11 ± 0.06) × 1039 erg s−1;it is thus a bonda fide pulsating ultraluminous X-ray source (PULX). Owing to the broad energy band of Insight-HXMT, its pulsed X-ray emission was detected from 1 keV up to the 130−180 keV band, which is the highest energy emission detected from any PULXs outside the Milky Way. This allows us to conclude that its main pulsed X-ray emission is from the "fan beam" of the accretion column, and its luminosity is thus intrinsic. We also estimate its magnetic field of (4.8−8.6)×1012 G or (1.7−2.2)×1013 G, from its spin evolution or transition in the accretion column structure during the outburst;we suggest that the two values of the magnetic field strength correspond to the dipole and multipole magnetic fields of the neutron star, similar to the recent discovery in the Galactic PULX Swift J0243.6+6124. Therefore, the nature of the neutron star and its ULX emission can be understood within the current theoretical frame of accreting neutron stars. This may have implications for understanding the nature of those farther away extragalactic PULXs. Copyright © 2022, The Authors. All rights reserved.

关键词： Luminance

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