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Supermassive Black Hole and Broad-line Region in NGC~5548: Results from Five-season Reverberation Mapping

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arXiv 2022年

作者： Lu, Kai-Xing Bai, Jin-Ming Wang, Jian-Min Hu, Chen Li, Yan-Rong Du, Pu Xiao, Ming Feng, Hai-Cheng Li, Sha-Sha Wang, Jian-Guo Zhang, Zhi-Xiang Huang, Ying-Ke Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing100049 China Department of Astronomy Xiamen University Fujian Xiamen361005 China Multi-disciplinary Research Division Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing100049 China

NGC 5548 is one of the active galactic nuclei (AGN) selected for our long-term spectroscopic monitoring with the Lijiang 2.4 m telescope, aiming at investigating the origin and evolution of the broad-line regions (BLRs), accurately measuring the mass of the supermassive black holes (SMBHs), and understanding structure and evolution of the AGN. We have performed five-season observations for NGC 5548 with the median sampling interval ranging from 1.25 to 3 days. The light curves of the 5100 Å continuum and broad emission lines are measured after subtracting contamination of the host galaxy starlight. The time lags of the broad He II, He I, Hγ, and Hβ lines with respect to the 5100 Å continuum are obtained for each season and their mean time lags over the five seasons are 0.69, 4.66, 4.60, 8.43 days, respectively. The Hγ and Hβ velocity-resolved lag profiles in the seasons of 2015, 2018, 2019, and 2021 are constructed, from which an "M-shaped" structure is found in 2015 but disappears after 2018. Our five-season reverberation mapping (RM) yields an averaged virial SMBH mass of M•/107Mo = 14.22, with a small standard deviation of 1.89. By combining the previous 18 RM campaigns and our five-season campaign for NGC 5548, we find that there exists a time lag of 3.5 years between the changes in the BLR size and optical luminosity. In addition, we also construct the BLR radius−luminosity relation and the virial relation for NGC 5548. © 2022, CC BY.

关键词： Active Galactic Nuclei

Detection of 2460 SB2 candidates in the LAMOST-MRS, using projected rotational velocities and a binary spectral model

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arXiv 2022年

作者： Kovalev, Mikhail 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 Leninskie Gory Moscow119992 Russia Max Planck Institute for Astronomy HeidelbergD-69117 Germany Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We present a new method for the detection of double-lined spectroscopic binaries (SB2) using V sin ί values from spectral fits. The method is tested on synthetic and real spectra from LAMOST-MRS. It can reliably detect SB2 candidates for double-lined binaries with V sin ί1 + V sin ί2 −1 if the radial velocity separation is large enough. Using this method, we detect 2460 SB2 candidates, 1410 of which are new discoveries. We confirm the correlation between the radial velocity separation estimated by the binary model and V sin ί0 estimated by the single star model using the selected sample. Additionally, our method finds one new SB2 candidate in open cluster M 11. Copyright © 2022, The Authors. All rights reserved.

关键词： Stars

Radial stellar populations of AGN-host dwarf galaxies in SDSS-IV MaNGA survey

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arXiv 2021年

作者： Cai, Wei Zhao, Yinghe Bai, Jin-Ming Yunnan Observatories Chinese Academy of Sciences Kunming652016 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China

Based on MaNGA integral field unit (IFU) spectroscopy we search 60 AGN candidates, which have stellar masses M? 6 5×109M and show AGN ionization signatures in the BPT diagram. For these AGN candidates, we derive the spatially resolved stellar population with the stellar population synthesis code STARLIGHT and measure the gradients of the mean stellar age and metallicity. We find that the gradients of mean stellar age (metallicity) of individual AGN-host dwarfs are diverse in 0−0.5 Re, 0.5−1 Re and 0−1 Re. However, the overall behavior of the mean stellar age (metallicity) profiles tend to be flat, as the median values of the gradients are close to zero. We further study the overall behavior of the mean stellar age (metallicity) by plotting the co-added radial profiles for the AGN sample and compare with a control sample with similar stellar mass. We find that the median values of light-weighted mean stellar ages of AGN sample are as old as 2−3 Gyr within 2 Re,which are about 4−7 times older than those of the control sample. Meanwhile, most of the AGN candidates are low-level AGNs, as only eight sources have L[O III]>1039.5 erg s−1. Hence, the AGNs in dwarf galaxies might accelerate the evolution of galaxies by accelerating the consumption of the gas, resulting in an overall quenching of the dwarf galaxies, and the AGNs also become weak due to the lack of gas. The median values of mass-weighted mean stellar age of both samples within 2 Re are similar and as old as about 10 Gyr, indicating that the stellar mass is mainly contributed by old stellar populations. The gradients of co-added mean stellar metallicity for both samples tend to be negative but close to zero, and the similar mean stellar metallicity profiles for both samples indicate that the chemical evolution of the host galaxy is not strongly influenced by the AGN. Copyright © 2021, The Authors. All rights reserved.

关键词： Galaxies

evolutionary Population Synthesis model with binary stars – Yunnan-II model

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Proceedings of the International Astronomical Union 2020年第S341期15卷 35-38页

作者： F. Zhang Z. Han L. Li National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China email: zhangfh@***

By considering a modified version of the evolutionary population synthesis (EPS) model for stellar populations (SPs) comprising binary stars, the retrieved galaxy and HII-region parameters/properties differ from the case of neglecting binary stars. The retrieved age, stellar metallicity and mass of galaxies increase (e.g. ∼ 0.2 dex when using spectral fitting algorithm), whilst the star formation rate decreases (∼0.2 dex). The radiation fields from intermediate-age SPs with binary stars could be potentially important ionizing sources in HII regions. Under this possibility, the theoretical division between star forming galaxy and AGN on the diagnostic diagrams would move towards the up-right corner and the retrieved gaseous metallicity would *** prediction for the birth rate of binary neutron stars in SPs ranges from 10−9 to 10−6${\M {^\minus 1_\odot}} $ yr−1 when the kick velocity is from 0 to 190 km s−1.

关键词： galaxies: stellar content galaxies: fundamental parameters galaxies: evolution stars: neutron

Comparative study of TESS photometry and radial velocities on six early K-type contact binaries with similar periods around 0.268 days

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arXiv 2023年

作者： Liu, Nian-Ping Qian, S.-B. Liao, W.-P. Huang, Y. Yuan, Z.-L. Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 Kunming650216 China Key Laboratory for 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# Shijingshan Block Beijing100049 China South-Western Institute for Astronomy Research Yunnan University Kunming650500 China Department of Physics School of Physics and Electronics Hunan Normal University P.O. Box 110 Changsha410081 China

High-precision light curves were extracted from TESScut images. Together with APOGEE and LAMOST medium resolution spectra, a joint study was made for six early K-type contact binary candidates selected unbiasedly with orbital periods around 0.268 days. It is found that all of them (RV CVn, EK Com, V384 Ser, V1038 Her, EH CVn, and CSS J125403.7+503945) are W-subtype shallow contact systems though with different mass ratios (1/q = 0.27–0.62). The effective temperature differences between binary components are around a few hundred Kelvins. The original definition of A- and W-subtypes were compared with the customarily used methods which rely on the shape or on the photometric solutions of light curves. The latter two methods are not always reliable and therefore the radial velocity analysis is strongly recommended. Through a collection of all available K-type contact binaries with both photometric and spectroscopic measurements, it is found that almost all of them are W-subtype systems, except a few objects which have nearly identical temperatures for binary components. This W-subtype phenomenon for K-type contact binaries should be further checked with more samples in the future. Finally, the physical parameters of the targets were determined with joint data analysis and the multiplicity is discussed for these targets. V384 Ser and RV CVn are confirmed very likely to be triple systems from comprehensive analysis, while V1038 Her is a candidate of a triple system based on photometric and spectroscopic solutions. Copyright © 2023, The Authors. All rights reserved.

关键词： Stars

Fundamental parameters for dEB SB2 binary system J064726.39+223431.6

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arXiv 2022年

作者： Kovalev, Mikhail Wang, Song 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 M. v. Lomonosov Moscow State University Leninskie Gory Moscow119991 Russia Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We present a study of the detached eclipsing binary J064726.39+223431.6 using spectra from the LAMOST medium-resolution spectra and TESS photometry. We use full-spectrum fitting to derive radial velocities and spectral parameters: (formula presented) and (formula presented). The orbital solution and light curve analysis suggest that it is a close pair of fast rotating stars on a circular orbit. We measure their masses to be (formula presented) and their radii to be (formula presented) resulting in surface gravities of log (g) (formula presented). Theoretical models cannot match all of these properties, predicting significantly higher Teff for a given metallicity. The derived age of the system is 1.56 Gyr, which indicates that both components are younger than Sun, which contradicts to much longer orbit’s circularisation timescale. Copyright © 2022, The Authors. All rights reserved.

关键词： Stars

Broadband multi-wavelength study of LHAASO detected AGN

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arXiv 2023年

作者： Wang, Ze-Rui Xue, Rui Xiong, Dingrong Wang, Hai-Qin Sun, Lu-Ming Peng, Fang-Kun Mao, Jirong College of Physics and Electronic Engineering Qilu Normal University Jinan250200 China Department of Physics Zhejiang Normal University Jinhua321004 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 Department of Physics Anhui Normal University Wuhu241002 China

Recently, the Large High Altitude Air Shower Observatory (LHAASO) collaboration presented the first catalog of γ-ray sources using 508 days of LHAASO data, from March 2021 to September 2022. This catalog contains four blazars and a possible liner-type AGN counterpart. In this work, we establish averaged multi-wavelength SEDs by combining data from the Fermi-Large Area Telescope, Swift, ZTF, and WISE covering the same period as the LHAASO detection. In general, these five AGNs are found in low states at all wavelengths. To study the multi-wavelength properties of these AGNs, several jet emission models, including the one-zone leptonic model, the one-zone leptonic and hadronuclear (pp) model, the one-zone proton-synchrotron model, and the spine-layer model are applied to reproduce their averaged SEDs, respectively. We find that the one-zone leptonic model can reproduce most of the SEDs, except for the high-energy tail of the LHAASO spectra of Mrk 421 and Mrk 501. To improve the fitting, emission from pp interactions is favoured in the framework of a one-zone model. The spine-layer model, which can be treated as a multi-zone scenario, can also provide good spectral fits. The influence of different extragalactic background light models on fitting LHAASO energy spectrum is also discussed. © 2023, CC BY.

关键词： Astrophysics

V606 Cen: A newly formed massive contact binary in a hierarchical triple system

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arXiv 2023年

作者： Li, F.-X. Liao, W.-P. Qian, S.-B. Fernández Lajús, E. Zhang, J. Zhao, E.-G. P.O. Box 110 Kunming650216 China University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China Key Laboratory of the Structure and Evolution of Celestial Objects CAS Kunming650216 China Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque s/n La Plata Buenos Aires 1900 Argentina Instituto de Astrofísica de La Plata CCT La Plata CONICET UNLP La Plata1900 Argentina

V606 Centauri (V606 Cen) is an early B-type close binary with an orbital period of 1.4950935 d and the complete light curves are very difficult to be observed on the ground. By analyzing the continuous light curve obtained by TESS, we found that it is a marginal contact binary with a very low fill-out factor of about 2%. The O-C diagram of V606 Cen is constructed for the first time based on the 118.8-years of eclipse times. The O-C diagram has been found to show a downward parabolic change together with a cyclic oscillation with a semi-amplitude of 0.0545 d and a period of 88.3 yr. The downward parabolic variation reveals a linear period decrease at a rate of dP/dt = −2.08 × 10−7d · yr−1 that can be explained by the mass transfer from the more massive component to the less massive one. Both the marginal contact configuration and the continuous period decrease suggest that V606 Cen is a newly formed contact binary via Case A mass transfer. The cyclic change in the O-C diagram can be explained by the Light-Travel Time Effect via the presence of a third body. The lowest mass of the tertiary companion is determined as M3 = 4.51(±0.43)Mo and the tertiary is orbiting around the central eclipsing binary in a nearly circular orbit (e=0.33). All the results indicate that V606 Cen is a newly formed massive contact binary in a hierarchical triple system. © 2023, CC BY.

关键词： Mass transfer

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