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

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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

Criteria for Dynamical Timescale Mass Transfer of Metal-poor Intermediate-mass Stars

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arXiv 2023年

作者： Ge, Hongwei Tout, Christopher A. Chen, Xuefei Sarkar, Arnab Walton, Dominic J. Han, Zhanwen Yunnan Observatories Chinese Academy of Sciences 396 YangFangWang Guandu District Kunming650216 China Institute of Astronomy The Observatories University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O. Box 110 Kunming650216 China Centre for Astrophysics Research University of Hertfordshire College Lane HatfieldAL10 9AB United Kingdom University of Chinese Academy of Sciences Beijing100049 China

The stability criteria of rapid mass transfer and common envelope evolution are fundamental in binary star evolution. They determine the mass, mass ratio and orbital distribution of many important systems, such as X-ray binaries, Type Ia supernovae and merging gravitational wave sources. We use our adiabatic mass-loss model to systematically survey the intermediate-mass stars' thresholds for dynamical-timescale mass transfer. The impact of metallicity on the stellar responses and critical mass ratios is explored. Both tables (Z = 0.001) and fitting formula (Z = 0.001 and Z = 0.02) of critical mass ratios of intermediate-mass stars are provided. An application of our results to intermediate-mass X-ray binaries (IMXBs) is discussed. We find that the predicted upper limit to mass ratios, as a function of orbital period, is consistent with the observed IMXBs that undergo thermal or nuclear timescale mass transfer. According to the observed peak X-ray luminosity LX, we predict the range of LX for IMXBs as a function of the donor mass and the mass transfer timescale. Copyright © 2023, The Authors. All rights reserved.

关键词： Mass transfer

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

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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

A systematic search for dual agns in merging galaxies (astro-daring): II: First results from long-slit spectroscopic observations

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arXiv 2021年

作者： Zhang, Yang-Wei Huang, Yang Bai, Jin-Ming Liu, Xiao-Wei Wang, Jian-Guo Dong, Xiao-Bo Yunnan Observatories Chinese Academy of Sciences Yunnan Kunming650011 China South-Western Institute for Astronomy Research Yunnan University Kunming650500 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

Building a large sample of kiloparsec (kpc)-scale dual active galactic nuclei (AGNs) amongst merging galaxies is of vital importance to understand the co-evolution between host galaxies and their central super massive black holes (SMBHs). Doing so, with just such a sample, we have developed an innovative method of systematically searching and identifying dual AGNs of amongst kpc scale merging galaxies and selected 222 candidates at redshifts 6 0.25. All the selected candidates have FIRST radio detection and at least one of two cores previously revealed as AGN spectroscopically. We report the first results from A SysTematic seaRch fOr Dual Agns in meRgINg Galaxies (ASTRO-DARING), which consist of spatially resolved long-slit spectroscopic observations of 41 targets selected from our merging galaxies sample carried out between November 2014 and February 2017, using the Yunnan Faint Object Spectrograph and Camera (YFOSC) mounted on the 2.4 meter telescope in Lijiang of Yunnan Observatories. Of these 16 are likely dual AGNs and 15 are newly identified. The efficiency of ASTRO-DARING is thus nearly 40 per cent. With this method, we plan to build the first even sample of more than 50 dual AGNs constructed using a consistent approach. Further analysis of the dual AGN sample shall provide vital clues for understanding the co-evolution of galaxies and SMBHs. Copyright © 2021, The Authors. All rights reserved.

关键词： Galaxies

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

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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

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

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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

A SysTematic seaRch for dual agns in meRgINg galaxies (ASTRO-DARING) III: Results from the SDSS spectroscopic surveys

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arXiv 2021年

As the third installment in a series systematically searching dual active galactic nuclei (AGN) amongst merging galaxies, we present the results of 20 dual AGNs found by using the SDSS fiber spectra. To reduce the flux contamination from both the fiber aperture and seeing effects, the angular separation of two cores in our merging galaxy pairs sample is restricted at least larger than 3′′. By careful analysis of the emission lines, 20 dual AGNs are identified from 61 merging galaxies with their two cores both observed by the SDSS spectroscopic surveys. 15 of them are identified for the first time. The identification efficiency is about 32.79% (20/61), comparable to our former results (16 dual AGNs identified from 41 merging galaxies) based on the long-slit spectroscopy. Interestingly, two of the 20 dual AGNs show two prominent cores in radio images and their radio powers show they as the radio-excess AGNs. So far, 31 dual AGNs are found by our project and this is the current largest dual AGN sample, ever constructed with a consistent approach. This sample, together with more candidates from ongoing observations, is of vital importance to study the AGN physics and the coevolution between the supermassive black holes and their host galaxies. Copyright © 2021, The Authors. All rights reserved.

关键词： Galaxies

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

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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

Can one-zone hadronuclear model explain the hard-TeV spectrum of BL Lac objects?

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arXiv 2022年

作者： Li, Wei-Jian Xue, Rui Long, Guang-Bo Wang, Ze-Rui Nagataki, Shigehiro Yan, Da-Hai Wang, Jian-Cheng Department of Physics Zhejiang Normal University Jinhua321004 China School of Physics Sun Yat-Sen University GuangDong Guangzhou China College of Physics and Electronic Engineering Qilu Normal University Jinan250200 China RIKEN Saitama351-0198 Japan RIKEN Saitama351-0198 Japan Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

Context. The intrinsic TeV emission of some BL Lacs are characterized by a hard spectrum (the hard-TeV spectrum) after correcting for the extragalactic background light. The hard-TeV spectra pose a challenge to conventional one-zone models, including the leptonic model, the photohadronic model, the proton synchrotron model, etc. Aims. In this work, we study if the one-zone hadronuclear (pp) model can be used to interpret the hard-TeV spectra of BL Lacs without introducing extreme parameters. Methods. We give analytical calculations to study if there is a parameter space and the charge neutrality condition of jet can be satisfied when interpreting the hard-TeV spectra of BL Lacs without introducing a super-Eddington jet power. Results. We find that in a sample of hard-TeV BL Lacs collected by Xue et al. (2019a), only the hard-TeV spectrum of 1ES 0229+200 could be explained by γ-ray from π0 decay produced in the pp interactions, but at the cost of setting a small radius of the radiation region that comparable to the Schwarzschild radius of the central black hole. Combining with previous studies of other one-zone models, we suggest that the hard-TeV spectra of BL Lacs cannot be explained by any one-zone models without introducing extreme parameters, and should originate from the multiple radiation regions. © 2022, CC BY.

关键词： Gamma rays