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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

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The 2175 Ã bump features in FeLoBAL quasars: One indicator of MW-like dust in the nuclear region of quasars

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Astronomy and Astrophysics 2022年 663卷

作者： Zhang, Shaohua Ge, Jian Ji, Tuo Jiang, Peng Luo, Zhijian Pan, Xiang Shi, Xiheng Shu, Chenggang Wang, Jianguo Xiao, Hubing Zhou, Hongyan Shanghai Key Lab For Astrophysics Shanghai Normal University Shanghai200234 China Key Laboratory For Research In Galaxies And Cosmology Shanghai Astronomical Observatory Chinese Academy Of Sciences Shanghai200030 China Key Laboratory Of Polar Science Polar Research Institute Of China Ministry Of Natural Resources Shanghai200136 China Key Laboratory For The Structure And Evolution Of Celestial Objects Yunnan Observatories Chinese Academy Of Sciences Kunming Yunnan650011 China Key Laboratory For Research In Galaxies And Cosmology Department Of Astronomy University Of Science And Technology Of China Chinese Academy Of Sciences Hefei Anhui230026 China School Of Astronomy And Space Science University Of Science And Technology Of China Hefei Anhui230026 China

To investigate the properties of dust in the nuclear region of quasars, we explored the extinction curves of the iron low-ionisation broad absorption line (FeLoBAL) quasar SDSS J163004.29+311957.6 and its two analogues. The parametrised extinction curves indicated the Milky Way-like 2175 Ã bump features in underlying extinction, which are similar to those seen in the Local Group and in a subset of high-redshift star-forming galaxies. Compared to the bump features in the Large Magellanic Cloud (LMC), the detections in this work are much closer to those in the Milky Way (MW). These bump features, as well as those in the high-and low-ionisation broad absorption line (BAL) quasars with 2175 Ã bumps, are probably the counterpart of the 2175 Ã bump features in the quasar environment. This type of dust grain is generally small, easily disrupted by high-energy photons, and has difficulty surviving in the radiation field of the active galactic nucleus. However, due to the presence of absorption-line outflows, the 2175 Ã bump feature in quasars, which should be rare, is seen many times in BAL quasars. The shielding effect of outflow clouds allows the MW-like dust grains to be assembled or extends the survival period in the quasar nuclear region. The process and physical and chemical conditions deserve further observational study and investigation. © 2022 ESO.

关键词： Dust

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

arXiv

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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

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A possibly solar metallicity atmosphere escaping from HAT-P-32b revealed by Hα and He absorption

arXiv

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arXiv 2024年

作者： Yan, Dongdong Guo, Jianheng Seon, Kwang-Il López-Puertas, Manuel Czesla, Stefan Lampón, Manuel Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 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 Astronomy and Space Science University of Chinese Academy of Sciences Beijing China Korea Astronomy & Space Science Institute 776 Daedeokdae-ro Yuseong-gu Daejeon34055 Korea Republic of University of Science and Technology 217 Gajeong-ro Yuseong-gu Daejeon34113 Korea Republic of Glorieta de la Astronomía s/n Granda 18008 Spain Thüringer Landessternwarte Tautenburg Sternwarte 5 TautenburgD-07778 Germany

This paper presents a hydrodynamic simulation that couples detailed non-local thermodynamic equilibrium (NLTE) calculations of the hydrogen and helium level populations to model the Hα and He 10830 transmission spectra of the hot Jupiter HAT-P-32b. A Monte Carlo simulation is applied to calculate the number of Lyα resonance scatterings, which is the main process for populating H(2). In the examined parameter space, only the models with H/He ≥ 99.5/0.5, (0.5 ∼ 3.0) times the fiducial value of FXUV, βm = 0.16 ∼ 0.3, can explain the Hα and He 10830 lines simultaneously. We find a mass-loss rate of ∼ (1.0 ∼ 3.1)×1013 g s−1, consistent with previous studies. Moreover, we find that the stellar Lyα flux should be as high as 4 × 105 erg cm−2 s−1, indicating high stellar activity during the observation epoch of the two absorption lines. Despite the fact that the metallicity in the lower atmosphere of HAT-P-32b may be super-solar, our simulations tentatively suggest it is close to solar in the upper atmosphere. The difference in metallicity between the lower and upper atmospheres is essential for future atmospheric characterisations. © 2024, CC BY-NC-ND.

关键词： Monte Carlo methods

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A flexible method for estimating luminosity functions via Kernel Density Estimation - II. Generalization and Python implementation

arXiv

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arXiv 2022年

作者： Yuan, Zunli Zhang, Xibin Wang, Jiancheng Cheng, Xiangming Wang, Wenjie 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 Department of Econometrics and Business Statistics Monash University Australia 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

We propose a generalization of our previous KDE (kernel density estimation) method for estimating luminosity functions (LFs). This new upgrade further extend the application scope of our KDE method, making it a very flexible approach which is suitable to deal with most of bivariate LF calculation problems. From the mathematical point of view, usually the LF calculation can be abstracted as a density estimation problem in the bounded domain of {Z1 2, L > flim(z)}. We use the transformation-reflection KDE method (φ) to solve the problem, and introduce an approximate method (φ1) based on one-dimensional KDE to deal with the small sample size case. In practical applications, the different versions of LF estimators can be flexibly chosen according to the Kolmogorov-Smirnov test criterion. Based on 200 simulated samples, we find that for both cases of dividing or not dividing redshift bins, especially for the latter, our method performs significantly better than the traditional binning method φbin. Moreover, with the increase of sample size n, our LF estimator converges to the true LF remarkably faster than φbin. To implement our method, we have developed a public, open-source Python Toolkit, called kdeLF. With the support of kdeLF, our KDE method is expected to be a competitive alternative to existing nonparametric estimators, due to its high accuracy and excellent stability. kdeLF is available at http://***/yuanzunli/kdeLF with extensive documentation available at http://***/en/latest . Copyright © 2022, The Authors. All rights reserved.

关键词： High level languages

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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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Physical Parameters of 11,100 Short-Period ASAS-SN Eclipsing Contact Binaries

arXiv

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arXiv 2024年

作者： Li, Xu-Zhi Zhu, Qing-Feng Ding, Xu Xu, Xiao-Hui Zheng, Hang Qiu, Jin-Sheng Liu, Ming-Chao 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 Sciences 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 Yunnan Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China University of the Chinese Academy of Sciences Yuquan Road 19 Shijingshan Block Beijing100049 China

Starting from more than 11,200 short-period (less than 0.5 days) EW-type eclipsing binary candidates with the All-Sky Automated Survey for Supernovae (ASAS-SN) V-band light curves, we use MCMC and neural networks (NNs) to obtain the mass ratio (q), orbital inclination (incl), fill-out factor (f) and temperature ratio (Ts/Tp). After cross-matching with the Gaia DR3 database, the final sample contains parameters of 2,399 A-type and 8,712 W-type contact binaries (CBs). We present the distributions of parameters of these 11,111 short-period CBs. The mass ratio (q) and fill-out factor (f) are found to obey log-normal distributions, and the remaining parameters obey normal distributions. There is a significant period-temperature correlation of these CBs. Additionally, the temperature ratio (Ts/Tp) tends to increase as the orbital period decreases for W-type CBs. There is no significant correlation between them for A-type CBs. The mass ratio and fill-out factor (q − f) diagram suggest there is no significant correlation between these two parameters. A clear correlation exists between the mass ratio and radius ratio. The radius ratio increases with the mass ratio. Moreover, the deep fill-out CBs tend to fall on the upper boundary of the q−Rs/Rp distribution, while the shallow fill-out CBs fall on the lower boundary. © 2024, CC BY.

关键词： Normal distribution

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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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Timing analysis of EXO 2030+375 during its 2021 giant outburst observed with Insight-HXMT

arXiv

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arXiv 2023年

作者： Fu, Yu-Cong Song, L.M. Ding, G.Q. Ge, M.Y. Tuo, Y.L. Zhang, S. Zhang, S.N. Hou, X. Qu, J.L. Zhang, J. Zhang, L. Bu, Q.C. Huang, Y. Ma, X. Zhou, X. Yan, W.M. Yang, Z.X. Lu, X.F. Li, T.M. Xu, Y.C. Wang, P.J. Xiao, S.H. Liu, H.X. Ren, X.Q. Du, Y.F. Zhao, Q.X. Xiao, Y.X. Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi Xinjiang830011 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 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 Institut für Astronomie und Astrophysik Kepler Center for Astro and Particle Physics Eberhard Karls Universität Sand 1 Tübingen72076 Germany Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210008 China Xinjiang Key Laboratory of Radio Astrophysics Urumqi830011 China

We report the evolution of the X-ray pulsations of EXO 2030+375 during its 2021 outburst using the observations from Insight-HXMT. Based on the accretion torque model, we study the correlation between the spin frequency derivatives and the luminosity. Pulsations can be detected in the energy band of 1–160 keV. The pulse profile evolves significantly with luminosity during the outburst, leading to that the whole outburst can be divided into several parts with different characteristics. The evolution of the pulse profile reveals the transition between the super-critical (fan-beam dominated) and the sub-critical accretion (pencil-beam dominated) mode. From the accretion torque model and the critical luminosity model, based on a distance of 7.1 kpc, the inferred magnetic fields are (0.41 − 0.74) × 1012 G and (3.48 − 3.96) × 1012 G, respectively, or based on a distance of 3.6 kpc, the estimated magnetic fields are (2.4 − 4.3) × 1013 G and (0.98 − 1.11) × 1012 G, respectively. Two different sets of magnetic fields both support the presence of multipole magnetic fields of the NS. © 2023, CC BY-NC-ND.

关键词： Luminance

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Analysis of the possible satellite contamination in LAMOST-MRS spectra

arXiv

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arXiv 2023年

作者： Kovalev, Mikhail Hainaut, Olivier R. Chen, Xuefei Han, Zhanwen Yunnan Observatories China Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Sternberg Astronomical Institute of the M. V. Lomonosov Moscow State University Leninskie Gory Moscow119992 Russia European Southern Observatory Karl-Schwarzschild-Straße 2 Garching bei München85748 Germany Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We present the detection of false positive double-lined spectroscopic binaries candidates (SB2) using medium-resolution survey (MRS) spectra from the one time-domain field of LAMOST data release 10 (DR10). The secondary component in all these binaries has near zero radial velocity and solar-like spectral lines. Highly likely this is light from the semi-transparent clouds illuminated by the full Moon. However we also suspect that partially this contamination can be caused by a solar light reflected from the surface of low-orbital artificial satellites launched in the beginning of 2022. We found several possible contaminant candidates using archival orbital data. We propose measures to reduce risk of such contamination for the future observations and methods to find it in archived ones. Copyright © 2023, The Authors. All rights reserved.

关键词： Contamination

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