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Photometric Analysis of the eclipsing Polar MN Hya

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arXiv 2018年

作者： Wang, Qi-Shan Qian, Sheng-Bang Han, Zhong-Tao Zejda, Miloslav Fernández-Lajus, Eduardo Zhu, Li-Ying P. O. Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China Department of Theoretical Physics and Astrophysics Masaryk University Kotlár ská 2 Brno611 37 Czech Republic Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque s/n La Plata Pcia. Bs. As1900 Argentina Argentina

As an eclipsing polar with 3.39 hrs orbital period, MN Hya was going through state change when we observed it during 2009-2016. 10 new mid-eclipse times, along with others obtained from literature, allow us to give a new ephemeris. The residuals of linear fit show that period decreased during the phase of state change. It means angular momentum was lost during this phase. The X-ray observation indicates the mass accretion rate as about 3.6 × 10−9M☉yr−1. The period decrease gives that at least 60 percent of mass being transfered from secondary was lost, maybe in form of the spherically symmetric stellar wind. In high state, the data shows the intensity of the flickering reduced when system had higher accretion rate, and that flickering sticks out with primary timescale about 2 minutes, which implies the position of the threading point as about 30 radius of the white dwarf above the surface of it. The trend of light curves of the system in high state follows that of low state for a large fraction of phase interval from phase 0 to phase 0.4 since which the cyclotron feature is visible, and the primary intensity hump of light curves near phase 0.7 when the system is in high state did not appear on the curve when it is in low state. Those facts contradict the predictions of the two-pole model. Copyright © 2018, The Authors. All rights reserved.

关键词： Flickering

Kinematic properties of the dual AGN system J0038+4128 based on long-slit spectroscopy

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Research in Astronomy and Astrophysics 2016年第3期16卷 43-50页

作者： Yang-Wei Zhang Yang Huang Jin-Ming Bai Xiao-Wei Liu Jian-Guo Wang Yunnan Observatories Chinese Academy of SciencesKunming 650011China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China Department of Astronomy Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China University of Chinese Academy of Sciences Beijing 100049China

The study ofkiloparsec-scale dual active galactic nuclei （AGN） provides important clues for understanding the co-evolution between host galaxies and their central supermassive black holes undergoing a merging process. We present long-slit spectroscopy of J0038 ＋4128, a kiloparsec-scale dual AGN candidate, discovered recently by Huang et al., using the Yunnan Faint Object Spectrograph and Camera （YFOSC） mounted on the Lijiang 2.4-m telescope administered by Yunnan Observatories. From the long-slit spectra, we find that the average relative line-of-sight （LOS） velocity between the two nuclei （J0038＋4128N and J0038＋4128S） is about 150 km s-1. The LOS velocities of the emission lines from the gas ionized by the nuclei activities and of the absorption lines from stars governed by the host galaxies for different regions of J0038＋4128 exhibit the same trend. The same trend in velocities indicates that the gaseous disks are co-rotating with the stellar disks in this ongoing merging system. We also find several knots/giant H II regions scattered around the two nuclei with strong star formation revealed by the observed line ratios from the spectra. Those regions are also clearly detected in images from HST F336W/U-band and HST F555W/V-band.

关键词： techniques： spectroscopic -- galaxies： kinematics and dynamics -- galaxies： active -- galax- ies： interactions -- galaxies： nuclei -- galaxies： individual （J0038＋4128）

DE CVn: An eclipsing post-common envelope binary with a circumbinary disk and a giant planet

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arXiv 2018年

作者： Han, Z.-T. Qian, S.-B. Zhu, L.-Y. Zhi, Q.-J. Dong, A.-J. Soonthornthum, B. Poshyachinda, S. Sarotsakulchai, T. Fang, X.-H. Wang, Q.-S. Voloshina, Irina P. O. Box 110 Kunming650216 China Guizhou Provincial Key Laboratory of Radio Data Processing School of Physics and Electronic Sciences Guizhou Normal University Guiyang550001 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 Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China National Astronomical Research Institute of Thailand Ministry of Science and Technology Bangkok Thailand Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow119992 Russia

We present a timing analysis of the eclipsing post-common envelope binary (PCEB) DE CVn. Based on new CCD photometric observations and the published data, we found that the orbital period in DE CVn has a cyclic period oscillation with an amplitude of 28.08 s and a period of 11.22 years plus a rapid period decrease at a rate of P = -3.35 × 10-11ss-1. According to the evolutionary theory, secular period decreases in PCEBs arise from angular momentum losses (AMLs) driven by gravitational radiation (GR) and magnetic braking (MB). However, the observed orbital decay is too fast to be produced by AMLs via GR and MB, indicating that there could be other AML mechanism. We suggest that a circumbinary disk around DE CVn may be responsible for the additional AML. The disk mass was derived as a few × 10-4-10-3Mo, which is in agreement with that inferred from previous studies in the order of magnitude. The cyclic change is most likely result of the gravitational perturbation by a circumbinary object due to the Applegate's mechanism fails to explain such a large period oscillation. The mass of the potential third body is calculated as M3sin i′ = 0.011(±0.003)Mo. Supposing the circumbinary companion and the eclipsing binary is coplanar, its mass would correspond to a giant planet. This hypothetical giant planet is moving in a circular orbit of radius ∼ 5.75(±2.02) AU around its host star. Copyright © 2018, The Authors. All rights reserved.

关键词： Gravitation

Reddening and he I∗ λ10830 absorption lines in three narrow-line seyfert 1 galaxies

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arXiv 2017年

作者： Zhang, Shaohua Zhou, Hongyan Shi, Xiheng Liu, Wenjuan Pan, Xiang Jiang, Ning Ji, Tuo Jiang, Peng Wang, Shufen Polar Research Institute of China 451 Jinqiao Road Shanghai200136 China Key Laboratory for Researches in Galaxies and Cosmology Department of Astronomy University of Sciences and Technology of China Chinese Academy of Sciences Hefei Anhui230026 China Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan650011 China

We report the detection of heavy reddening and the He I∗ λ10830 absorption lines at the AGNs' redshift in three Narrow-line Seyfert 1 galaxies: SDSS J091848.61+211717.0, SDSS J111354.66+124439.0, and SDSS J122749.13+321458.9. They exhibit very red optical to nearinfrared colors, narrow Balmer/Paschen broad emission lines and He I∗ λ10830 absorption lines. The ultraviolet-optical-infrared nucleus continua are reddened by the SMC extinction law of E(B - V ) ∼ 0.74, 1.17, and 1.24 mag for three objects, which are highly consistent with the values obtained from the broad-line Balmer decrements, but larger than those of narrow emission lines. The reddening analysis suggests the extinction dust simultaneously obscure the accretion disk, the broad emission line region, and the hot dust from the inner edge of the torus. It is possible that the dust obscuring the AGN structures are the dusty torus itself. Furthermore, the Cloudy analysis of the He I∗ λ10830 absorption lines propose the distance of the absorption materials to be the extend scale of the torus. That greatly increases probabilities of the obscure and absorption materials being the dusty torus. Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

Physical properties and evolutionary status of the W-subtype contact binary V502 Oph with a stellar companion

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arXiv 2017年

作者： Xiao, Zhou Shengbang, Qian Binghe, Huang Hao, Li Jia, Zhang Yunnan Observatories Chinese Academy of Sciences PO Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences PO Box 110 Kunming650216 China Graduate University of the Chinese Academy of Sciences Yuquan Road 19 Sijingshang Block Beijing100049 China

Multi-color (B V Rc Ic) CCD photometric light curves of the contact binary V502 Oph are analyzed using the Wilson-Devinney (W-D) program. The solutions reveal that V502 Oph is a W-subtype contact (f = 35.3%) binary system. The temperature difference between its two components is 240K and the more massive star has a lower surface temperature. A cool spot is added in our model to account for the light curves' asymmetry (O'Connell effect) and third light is detected for the first time in the light curves' modeling. Combining the orbital inclination (i = 76.4◦) with the published mass function of V502 Oph, the absolute physical parameters of the two components are determined, which are M1 = 0.46(±0.02)M☉, M2 = 1.37(±0.02)M☉, R1 = 0.94(±0.01)R☉, R2 = 1.51(±0.01)R☉, L1 = 1.13(±0.02)L☉ and L2 = 2.49(±0.03)L☉. The formation and evolutionary status of V502 Oph are discussed. All photoelectric and CCD times of light minimum about V502 Oph are gathered and its orbital period variations are analyzed. The results show that the orbital period of V502 Oph is decreasing continuously at a rate of dP/dt = −1.69 × 10−7day · year−1, which corresponds to a conservative mass transfer rate of dMdt2 = −3.01 × 10−8M☉/year. The light-travel time effect (LTTE) is due to the presence of a close-in tertiary component with a period of P3 = 18.7 years and an amplitute of 0.00402days. V502 Oph is an ideal target to test the formation and evolution theories of binary and multiple systems in which the light curves, O − C curve and spectroscopic observations are comprehensively researched. Copyright © 2017, The Authors. All rights reserved.

关键词： Travel time

A comprehensive K2 and ground-based study of crts j035905.9+175034, an eclipsing su uma system with a large mass ratio

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arXiv 2018年

作者： Littlefield, Colin Garnavich, Peter Kennedy, Mark Szkody, Paula Dai, Zhibin Department of Physics University of Notre Dame Notre DameIN46556 United States Jodrell Bank Centre for Astrophysics School of Physics and Astronomy University of Manchester M13 9PL United Kingdom Department of Astronomy University of Washington SeattleWA98195 United States 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

CRTS J035905.9+175034 is the first eclipsing SU UMa system for which a superoutburst has been observed by Kepler in the short-cadence mode. The light curve contains one superoutburst, eight normal outbursts (including a precursor to the superoutburst), and several minioutbursts that are present before-but not after-the superoutburst. The superoutburst began with a precursor normal outburst, and shortly after the peak of the precursor, the system developed large-amplitude superhumps that achieved their maximum amplitude after just three superhump cycles. The period excess of the initial superhump period relative to the orbital period implies a mass ratio of 0.281±0.015, placing it marginally above most theoretical predictions of the highest-possible mass ratio for superhump formation. In addition, our analysis of the variations in eclipse width and depth, as well as the hot spot amplitudes, generally provides substantiation of the thermal-tidal instability model. The K2 data, in conjunction with our ground-based time-resolved spectroscopy and photometry from 2014-2016, allows us to determine many of the fundamental parameters of this system. Copyright © 2018, The Authors. All rights reserved.

关键词： Laser spectroscopy

Discovery of an active intermediate-mass black hole candidate in the barred bulgeless galaxy NGC 3319

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arXiv 2018年

作者： Jiang, Ning Wang, Tinggui Zhou, Hongyan Shu, Xinwen Yang, Chenwei Dou, Liming Sun, Luming Dong, Xiaobo Wang, Shaoshao Yang, Huan 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 Sciences University of Science and Technology of China Hefei Anhui230026 China Polar Research Institute of China 451 Jinqiao Road Shanghai200136 China Department of Physics Anhui Normal University Wuhu Anhui241000 China Center for Astrophysics Guangzhou University Guangzhou510006 China Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming Yunnan650011 China Las Campanas Observatory Carnegie Institution for Science Casilla 601 La Serena Chile

We report the discovery of an active intermediate-mass black hole (IMBH) candidate in the center of nearby barred bulgeless galaxy NGC 3319. The point X-ray source revealed by archival Chandra and XMM−Newton observations is spatially coincident with the optical and UV galactic nuclei from Hubble Space Telescope observations. The spectral energy distribution derived from the unresolved X-ray and UV-optical flux is comparable with active galactic nuclei (AGNs) rather than ultra-luminous X-ray sources, although its bolometric luminosity is only 3.6 × 1040 erg s−1. Assuming an Eddington ratio range between 0.001 and 1, the black hole mass (MBH) will be located at 3 × 102 − 3 × 105 M☉, placing it in the so-called IMBH regime and could be the one of the lowest reported so far. Estimates from other approaches (e.g., fundamental plane, X-ray variability) also suggest MBH. 105 M☉. Similar to other BHs in bulgeless galaxies, the discovered IMBH resides in a nuclear star cluster with mass of ∼ 6 × 106 M☉. The detection of such a low-mass BH offers us an ideal chance to study the formation and early growth of SMBH seeds, which may result from the bar-driven inflow in late-type galaxies with a prominent bar such as NGC 3319. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

EP240801a/XRF 240801B: An X-ray Flash Detected by the Einstein Probe and Implications of its Multiband Afterglow

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arXiv 2025年

作者： Jiang, Shuai-Qing Xu, Dong van Hoof, Agnes P.C. Lei, Wei-Hua Liu, Yuan Zhou, Hao Chen, Yong Fu, Shao-Yu Yang, Jun Liu, Xing Zhu, Zi-Pei Filippenko, Alexei V. Jonker, Peter G. Pozanenko, A.S. Gao, He Wu, Xue-Feng Zhang, Bing Lamb, Gavin P. De Pasquale, Massimiliano Kobayashi, Shiho Bauer, Franz Erik Sun, Hui Pugliese, Giovanna An, Jie D’Elia, Valerio Fynbo, Johan P.U. Zheng, WeiKang Tirado, Alberto J.C. Yin, Yi-Han Iris Zou, Yuan-Chuan Deller, Adam T. Pankov, N.S. Volnova, A.A. Moskvitin, A.S. Spiridonova, O.I. Oparin, D.V. Rumyantsev, V. Burkhonov, O.A. Egamberdiyev, Sh A. Kim, V. Krugov, M. Tatarnikov, A.M. Inasaridze, R. Levan, Andrew J. Malesani, Daniele Bjørn Ravasio, Maria E. Quirola-Vásquez, Jonathan van Dalen, Joyce N.D. Sánchez-Sierras, Javi Sánchez, Daniel Mata Littlefair, Stuart P. Chacón, Jennifer A. Torres, Manuel A.P. Chrimes, Ashley A. Sarin, Nikhil Martin-Carrillo, Antonio Dhillon, Vik Yang, Yi Brink, Thomas G. Davies, Rebecca L. Yang, Sheng Aryan, Amar Chen, Ting-Wan Kong, Albert K.H. Li, Wen-Xiong Li, Rui-Zhi Mao, Jirong Pérez-García, Ignacio Fernández-García, Emilio J. Andrews, Moira Farah, Joseph Fan, Zhou Gonzalez, Estefania Padilla Howell, D. Andrew Hartmann, Dieter Hu, Jing-Wei Jakobsson, Páll Li, Cheng-Kui Ling, Zhi-Xing McCully, Curtis Newsome, Megan Schneider, Benjamin Tinyanont, Kaew Samaporn Sun, Ning-Chen Terreran, Giacomo Tang, Qing-Wen Wang, Wen-Xin Xu, Jing-Jing Yuan, Wei-Min Zhang, Bin-Bin Zhao, Hai-Sheng Zhang, Juan National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Altay Astronomical Observatory Xinjiang836500 China Radboud University Nijmegen Department of Astrophysics IMAPP P.O. Box 9010 Nijmegen6500 GL Netherlands Department of Astronomy School of Physics Huazhong University of Science and Technology Wuhan430074 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Key Laboratory of Modern Astronomy and Astrophysics [Nanjing University Ministry of Education China Department of Astronomy University of California BerkeleyCA94720-3411 United States Space Research Institute Russian Academy of Sciences Profsoyuznaya ul. 84/32 Moscow117997 Russia National Research University "Higher School of Economics" Myasnitskaya ul. 20 Moscow101000 Russia Institutskiy Pereulok 9 Dolgoprudny141701 Russia School of Physics and Astronomy Beijing Normal University Beijing100875 China Institute for Frontier in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Nevada Center for Astrophysics University of Nevada Las Vegas NV89154 United States Department of Physics and Astronomy University of Nevada Las Vegas NV89154 United States Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom University of Messina MIFT Department Via F.S. D’Alcontres 31 Messina98166 Italy Instituto de Alta Investigación Universidad de Tarapacá Casilla 7D Arica Chile Anton Pannekoek Institute of Astronomy University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands RomaI-00133 It

We present multiband observations and analysis of EP240801a, a low-energy, extremely soft gammaray burst (GRB) discovered on August 1, 2024 by the Einstein Probe (EP) satellite, with a weak contemporaneous signal also detected by Fermi/GBM. Optical spectroscopy of the afterglow, obtained by GTC and Keck, identified the redshift of z = 1.6734. EP240801a exhibits a burst duration of 148 s in X-rays and 22.3 s in gamma-rays, with X-rays leading by 80.61 s. Spectral lag analysis indicates the gamma-ray signal arrived 8.3 s earlier than the X-rays. Joint spectral fitting of EP/WXT and Fermi/GBM data yields an isotropic energy Eγ,iso = (5.57+0−0.5450) × 1051 erg, a peak energy Epeak = 14.90+7−4.0871 keV, a fluence ratio S(25 − 50 keV)/S(50 − 100 keV) = 1.67+0−0.7446, classifying EP240801a as an X-ray flash (XRF). The host-galaxy continuum spectrum, inferred using Prospector, was used to correct its contribution for the observed outburst optical data. Unusual early R-band behavior and EP/FXT observations suggest multiple components in the afterglow. Three models are considered: two-component jet model, forward-reverse shock model and forward-shock model with energy injection. Both three provide resonable explanations. The two-component jet model and the energy injection model imply a relatively small initial energy and velocity of the jet in the line of sight, while the forward-reverse shock model remains typical. Under the two-component jet model, EP240801a may resemble GRB 221009A (BOAT) if the bright narrow beam is viewed on-axis. Therefore, EP240801a can be interpreted as an off-beam (narrow) jet or an intrinsically weak GRB jet. Our findings provide crucial clues for uncovering the origin of XRFs. Copyright © 2025, The Authors. All rights reserved.

关键词： Gamma rays

Using deep Residual Networks to search for galaxy-Lyα emitter lens candidates based on spectroscopic-selection

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arXiv 2018年

作者： Li, Rui Shu, Yiping Su, Jianlin Feng, Haicheng Zhang, Guobao Wang, Jiancheng Liu, Hongtao Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 University of Chinese Academy of Sciences Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 Purple Mountain Observatory Chinese Academy of Sciences 2 West Beijing Road Nanjing Jiangsu210008 China Institute of Astronomy University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom School of Mathematics Sun Yat-sen University Guangzhou China

More than one hundred galaxy-scale strong gravitational lens systems have been found by searching for the emission lines coming from galaxies with redshifts higher than the lens galaxies. Based on this spectroscopic-selection method, we introduce the deep Residual Networks (ResNet, a kind of deep Convolutional Neural Networks) to search for the galaxy-Lyα emitter (LAE) lens candidates by recognizing the Lyα emission lines coming from high redshift galaxies (2 Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies