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A new approach to constraining properties of AGN host galaxies by combining image and SED decomposition: testing upon the MBH − M✶ relation

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arXiv 2024年

作者： Yu, Haoran Fan, Lulu Han, Yunkun Sun, Weibin Zhang, Yihang Ding, Xuheng Xue, Yongquan 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 Deep Space Exploration Laboratory Hefei230088 China Yunnan Observatories 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 Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China School of Physics and Technology Wuhan University Wuhan430072 China

The outshining light from active galactic nuclei (AGNs) poses significant challenges in studying the properties of AGN host galaxies. To address this issue, we propose a novel approach which combines image decomposition and spectral energy distribution (SED) decomposition to constrain properties of AGN host galaxies. Image decomposition allows us to disentangle optical flux into AGN and stellar components, thereby providing additional constraints on the SED models to derive more refined stellar mass. To test the viability of this approach, we obtained a sample of 24 X-ray selected type I AGNs with redshifts ranging from 0.73 to 2.47. We estimated the stellar masses for our sample and found that our results are generally consistent with earlier estimates based on different methods. Through examining the posterior distribution of stellar masses, we find that our method could derive better constrained results compared to previous SED decomposition methods. With the derived stellar masses, we further studied the MBH−M✶ relation of our sample, finding a higher intrinsic scatter in the correlation for our entire sample compared to the local quiescent correlation, which could be caused by a few "black hole monsters" in our sample. We propose that based on our method, future works could extend to larger samples of high-redshift AGN host galaxies, thereby enhancing our understanding of their properties. © 2024, CC BY.

关键词： Active Galactic Nuclei

Helium enrichment during classical nova outbursts

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arXiv 2021年

作者： Guo, Yunlang Wu, Chengyuan Wang, Bo 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 Tsinghua University Beijing100084 China

Nova outbursts play an important role in the chemical evolution of galaxies, especially they are the main source of synthetic 13C, 15N, 17O and some radioactive isotopes like 22Na and 26Al. The enrichment of He in nova ejecta indicates that the accreted material may mix with the He-shell (He-mixing). The purpose of this work is to investigate how the He-mixing affects the nova outbursts in a systematic way. We evolved a series of accreting WD models, and found that the mass fraction of H and He in nova ejecta can be influenced by different He-mixing fractions significantly. We also found that both the nova cycle duration and ejected mass increase with the He-mixing fractions. Meanwhile, the nuclear energy generation rate of p-p chains decreases with the He-mixing fraction during the nova outbursts, whereas the CNO-cycle increases. The present work can reproduce the chemical abundances in the ejecta of some representative novae, such as GQ Mus, ASASSN-18fv, HR Del, T Aur and V443 Sct. This implies that the He-mixing process cannot be neglected when studying nova outbursts. This study also develops a He-mixing meter (i.e. He/H) that can be used to estimate the He-mixing fraction in classical nova systems. © 2021, CC0.

关键词： Mixing

Strong magnetic field inside degenerate relativistic plasma and the impacts on the neutrino transport in Core-Collapse Supernovae

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arXiv 2024年

作者： Luo, Yudong Zha, Shuai Kajino, Toshitaka School of Physics Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 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 School of Physics Peng Huanwu Collaborative Center for Research and Education International Research Center for Big-Bang Cosmology and Element Genesis Beihang University Beijing100191 China Graduate School of Science The University of Tokyo Tokyo113-0033 Japan National Astronomical Observatory of Japan Tokyo181-8588 Japan

We study the impacts of magnetic field on the neutrino transport inside corecollapse supernovae (CCSNe). Magnetic field quantizes the momentum of electrons and positrons, resulting in the modification of weak-interaction cross sections and the chemical potentials of electrons and positrons. We include these changes in the leakage scheme of neutrino transport and perform 1D CCSN simulations with GR1D, assuming the postbounce magnetic field strength of 1016-17 G. The results show that the neutrino opacities are enhanced due to the amplified interaction rates, resulting in a larger neutrinosphere. This further reduces the peak value of neutrino luminosities and their decay rates since neutrinos stay longer inside the neutrinosphere. Meanwhile, the neutrino mean energies are smaller shortly after bounce and reach their peak values at later times. As these neutrino properties are crucial in subsequent nucleosynthesis processes, including the νp-process, ν-process, and r-process, our findings suggest that the magnetic field may leave discernible marks on the abundance pattern of nucleosynthesis in CCSN. Copyright © 2024, The Authors. All rights reserved.

关键词： Magnetic fields

Type Ia supernova ejecta-donor interaction: explosion model comparison

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arXiv 2022年

作者： McCutcheon, C. Zeng, Y. Liu, Z.-W. Izzard, R.G. Pan, K.-C. Chen, H.-L. Han, Z. Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China Astrophysics Research Group Faculty of Engineering and Physics University of Surrey GuildfordGU2 7XH United Kingdom University of Chinese Academy of Sciences Beijing100049 China Department of Physics Institute of Astronomy National Tsing Hua University Hsinchu30013 Taiwan

In the single-degenerate scenario of Type Ia supernovae (SNe Ia), the interaction between high-speed ejected material and the donor star in a binary system is expected to lead to mass being stripped from the donor. A series of multi-dimensional hydrodynamical simulations of ejecta-donor interaction have been performed in previous studies most of which adopt either a simplified analytical model or the W7 model to represent a normal SN Ia explosion. Whether different explosion mechanisms can significantly affect the results of ejecta-donor interaction is still unclear. In this work, we simulate hydrodynamical ejecta interactions with a main-sequence (MS) donor star in two dimensions for two near-Chandrasekhar-mass explosion models of SNe Ia, the W7 and N100 models. We find that about 0.30 and 0.37 Mo of hydrogen-rich material are stripped from a 2.5 Mo donor star in a 2 day orbit by the SN Ia explosion in simulations with the W7 deflagration and N100 delayed-detonation explosion model, respectively. The donor star receives a kick of about 74 and 86 km s−1, respectively, in each case. The modal velocity, about 500 km s−1, of stripped hydrogen-rich material in the N100 model is faster than the W7 model, with modal velocity of about 350 km s−1, by a factor 1.4. Based on our results, we conclude that the choice of near-Chandrasekhar-mass explosion model for normal SNe Ia seems to not significantly alter the ejecta-donor interaction for a given main-sequence donor model, at least in 2D. Copyright © 2022, The Authors. All rights reserved.

关键词： Explosions

Distribution and evolution of Li abundance in red clump stars can be explained by the internal gravity waves

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arXiv 2024年

作者： Li, Xue-Feng Shi, Jian-Rong Li, Yan Yan, Hong-Liang Zhang, Jing-Hua Yunnan Observatories Chinese Academy of Sciences P.O.Box110 Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China CAS Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O.Box110 Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China

The study of Li phenomena in red clump (RC) stars can give us a deeper understanding of the structure and evolution of stars. Chanamé et al. (2022) explained the RC Li abundance distributions naturally using only standard post main sequence (MS) Li evolution models when the distribution of progenitor masses and the depletion of Li during the MS observed in MS stars were considered, thus neither extra Li depletion nor Li creation mechanism is required. Nevertheless, it is interesting to consider the effects of mixing caused by some extra mechanisms. By constructing different models, we find that the mixing caused by internal gravity waves can explain the observed Li abundances of RC stars with low mass progenitors. To explain that, we rely on the extra mixing induced by internal gravity waves that are excited at the bottom of the convective envelope at the red giant branch (RGB) stage. During the RGB stage, introducing the internal gravity waves can improve the diffusion coefficient and strengthen the mixing effect. The effective enrichment of Li occurs at the late RGB stage and requires the diffusion coefficient of H-burning shell to reach ∼ 108 cm2 s−1. Our models predict that the Li abundance decreases from ∼ 1.5 dex to ∼ 0.0 dex at the end of core He-burning stage, thereby revealing the ∼ 99% of the observed Li abundance distribution. The thermohaline mixing regulates the Li abundance of RGB stars, which combines with the internal gravity waves can explain the Li abundances of most giants. Copyright © 2024, The Authors. All rights reserved.

关键词： Diffusion

Meridional Circulation. I. A Formation Channel for Lithium-rich and Super Lithium-rich Red Clump Stars

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arXiv 2025年

作者： Li, Xue-Feng Shi, Jian-Rong Li, Yan Yan, Hong-Liang Zhang, Jing-Hua Yunnan Observatories Chinese Academy of Sciences P.O.Box110 Kunming650216 China CAS Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing100101 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O.Box110 Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China South-Western Institute for Astronomy Research Yunnan University Chenggong District Kunming650500 China

Current observations indicate that stars with higher rotation rates appear to maintain more surface lithium, and the majority of lithium-rich giants are indeed red clump stars. Hence, we investigate the mechanisms behind lithium enrichment in rotating red clump stars and the pathways to forming lithium-rich red clump stars. Meridional circulation is prevalent in the radiative zone of rotating giants. We model its radial mixing as a diffusion process and derive the corresponding diffusion coefficient based on its material transfer effect. Due to uncertainties in numerical calculations, we consider an average diffusion effect. Additionally, certain limiting conditions for the radial velocity of meridional circulation are incorporated. With varying input rotation velocities, we simulate the lithium evolution for red clump stars with this model. Our results indicate that the material transfer effect due to meridional circulation can efficiently transport beryllium, produced by H burning, into the convective envelope. This meridional circulation can lead to lithium enrichment, with a maximum lithium abundance increment approaching 3.0 dex. Consequently, it is capable of forming both lithium-rich and super lithium-rich red clump stars. The degree of lithium enrichment exhibits a strong positive correlation with the rotation velocity, i.e., faster red clump stars show more surface lithium. Furthermore, our models indicate that lithium-rich red clump stars are relatively young (∼ 106 yr), which aligns with observation evidences. Copyright © 2025, The Authors. All rights reserved.

关键词： Giant stars

Adiabatic Mass Loss in Binary Stars. V. Effects of Metallicity and Nonconservative Mass Transfer – Application in High Mass X-ray Binaries

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arXiv 2024年

作者： Ge, Hongwei Tout, Christopher A. Chen, Xuefei Wang, Song Xiong, Jianping Zhang, Lifu Liu, Qingzhong Han, Zhanwen Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Institute of Astronomy The Observatories University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory ChineseAcademy of Sciences Nanjing China

Binary stars are responsible for many unusual astrophysical phenomena, including some important explosive cosmic events. The stability criteria for rapid mass transfer and common-envelope evolution are fundamental to binary star evolution. They determine the mass, mass ratio, and orbital distribution of systems such as X-ray binaries and merging gravitational-wave sources. We use our adiabatic mass-loss model to systematically survey metal-poor and solar-metallicity donor thresholds for dynamical timescale mass transfer. The critical mass ratios qad are systematically explored and the impact of metallicity and nonconservative mass transfer are studied. For metal-poor radiative-envelope donors, qad are smaller than those for solar-metallicity stars at the same evolutionary stage. However, qad do the opposite for convective-envelope donors. Nonconservative mass transfer significantly decreases qad for massive donors. This is because it matters how conservative mass transfer is during the thermal timescale phase immediately preceding a delayed dynamical mass transfer. We apply our theoretical predictions to observed high-mass X-ray binaries that have overfilled their Roche lobes and find a good agreement with their mass ratios. Our results can be applied to study individual binary objects or large samples of binary objects with binary population synthesis codes. Copyright © 2024, The Authors. All rights reserved.

关键词： Stability criteria

Measuring the virial factor in SDSS DR5 quasars with redshifted Hβ and Fe II broad emission lines

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arXiv 2022年

作者： Liu, H.T. Feng, Hai-Cheng Li, Sha-Sha Bai, J.M. 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 Yunnan Kunming650011 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Beijing Chaoyang District100012 China University of Chinese Academy of Sciences Beijing100049 China

Under the hypothesis of gravitational redshift induced by the central supermassive black hole, and based on line widths and shifts of redward shifted Hβ and Fe II broad emission lines for a sample of 1973 z © 20... 详细信息

关键词： Galaxies

Constraints on cosmic star formation history via a new modeling of the radio luminosity function of star-forming galaxies

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arXiv 2023年

作者： Wang, Wenjie Yuan, Zunli Yu, Hongwei Mao, Jirong Department of Physics School of Physics and Electronics Hunan Normal University Changsha410081 China Key Laboratory of Low Dimensional Quantum Structures and Quantum Control Hunan Normal University Changsha410081 China Synergetic Innovation Center for Quantum Effects and Applications Institute of Interdisciplinary Studies Hunan Normal University Hunan Changsha410081 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

Context. Radio wavelengths offer a unique possibility to trace the total star-formation rate (SFR) in galaxies, both obscured and unobscured. To probe the dust-unbiased star-formation history, an accurate measurement of the radio luminosity function (LF) for star-forming galaxies (SFGs) is crucial. Aims. We make use of an SFG sample (5900 sources) from the Very Large Array (VLA) COSMOS 3 GHz data to perform a new modeling of the radio LF. By integrating the analytical LF, we aim to calculate the history of the cosmic SFR density (SFRD) from z ∼ 5 onwards. Methods. For the first time, we use both models of the pure luminosity evolution (PLE) and joint luminosity+density evolution (LADE) to fit the LFs directly to the radio data using a full maximum-likelihood analysis, considering the sample completeness correction. We also incorporate updated observations of local radio LFs and radio source counts into the fitting process to obtain additional constraints. Results. We find that the PLE model cannot be used to describe the evolution of the radio LF at high redshift (z > 2). By construct, our LADE models can successfully fit a large amount of data on radio LFs and source counts of SFGs from recent observations. The Akaike information criterion (AIC) also demonstrates that the LADE model is superior to the PLE model. We therefore conclude that density evolution is genuinely indispensable in modeling the evolution of SFG radio LFs. Our SFRD curve shows a good fit to the SFRD points derived by previous radio estimates. In view of the fact that our radio LFs are not biased, as opposed those of previous studies performed by fitting the 1/Vmax LF points, our SFRD results should be an improvement on these previous estimates. Below z ∼ 1.5, our SFRD matches a published multiwavelength compilation, while our SFRD turns over at a slightly higher redshift (2 © 2023, CC BY.

关键词： Luminance