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arXiv 2022年

作者： Ajello, M. Atwood, W.B. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Bellazzini, R. Berretta, A. Bhattacharyya, B. Bissaldi, E. Blandford, R.D. Bloom, E. Bonino, R. Bruel, P. Buehler, R. Burns, E. Buson, S. Cameron, R.A. Caraveo, P.A. Cavazzuti, E. Cibrario, N. Ciprini, S. Clark, C.J. Cognard, I. Coronado-Blázquez, J. Crnogorcevic, M. Cromartie, H. Crowter, K. Cutini, S. D’Ammando, F. De Gaetano, S. de Palma, F. Digel, S.W. Di Lalla, N. Dirirsa, F. Fana Di Venere, L. Domínguez, A. Ferrara, E.C. Fiori, A. Franckowiak, A. Fukazawa, Y. Funk, S. Fusco, P. Gammaldi, V. Gargano, F. Gasparrini, D. Giglietto, N. Giordano, F. Giroletti, M. Green, D. Grenier, I.A. Guillemot, L. Guiriec, S. Gustafsson, M. Harding, A.K. Hays, E. Hewitt, J.W. Horan, D. Hou, X. Jóhannesson, G. Keith, M.J. Kerr, M. Kramer, M. Kuss, M. Larsson, S. Latronico, L. Li, J. Longo, F. Loparco, F. Lovellette, M.N. Lubrano, P. Maldera, S. Manfreda, A. Martí-Devesa, G. Mazziotta, M.N. Mereu, I. Michelson, P.F. Mirabal, N. Mitthumsiri, W. Mizuno, T. Monzani, M.E. Morselli, A. Negro, M. Nieder, L. Ojha, R. Omodei, N. Orienti, M. Orlando, E. Ormes, J.F. Paneque, D. Parthasarathy, Aditya Pei, Z. Persic, M. Pesce-Rollins, M. Pillera, R. Poon, H. Porter, T.A. Principe, G. Racusin, J.L. Rainò, S. Rando, R. Rani, B. Ransom, S.M. Ray, P.S. Razzano, M. Razzaque, S. Reimer, A. Reimer, O. Roy, J. Sánchez-Conde, M. Saz Parkinson, P.M. Scargle, J. Scotton, L. Serini, D. Sgrò, C. Siskind, E.J. Smith, D.A. Spandre, G. Spiewak, R. Spinelli, P. Stairs, I. Suson, D.J. Swihart, S.J. Tabassum, S. Thayer, J.B. Theureau, G. Torres, D.F. Troja, E. Valverde, J. Wadiasingh, Z. Wood, K. Zaharijas, G. Department of Physics and Astronomy Clemson University Kinard Lab of Physics ClemsonSC29634-0978 United States Santa Cruz Institute for Particle Physics Department of Physics Department of Astronomy and Astrophysics University of California at Santa Cruz Santa CruzCA95064 United States Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy AIM CEA CNRS Université Paris-Saclay Université de Paris Gif-sur-Yvette F-91191 France Istituto Nazionale di Fisica Nucleare Sezione di Trieste TriesteI-34127 Italy Dipartimento di Fisica Università di Trieste TriesteI-34127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy National Centre for Radio Astrophysics Tata Institute of Fundamental Research Pune411 007 India Dipartimento di Fisica "M. Merlin" Università e del Politecnico di Bari via Amendola 173 BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy Laboratoire Leprince-Ringuet École polytechnique Centre national de la recherche scientifique Institut national de physique nucléaire de physique des particules Palaiseau F-91128 France Deutsches Elektronen Synchrotron Zeuthen D-15738 Germany Department of Physics and Astronomy Louisiana State University Baton RougeLA70803 United States Institut für Theoretische Physik and Astrophysik Unive

After large galaxies merge, their central supermassive black holes are expected to form binary systems whose orbital motion generates a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background utilize pulsar timing arrays, which perform long-term monitoring of millisecond pulsars (MSPs) at radio wavelengths. We use 12.5 years of Fermi Large Area Telescope data to form a gamma-ray pulsar timing array. Results from 35 bright gamma-ray pulsars place a 95% credible limit on the GWB characteristic strain of 1.0 × 10−14 at 1 yr−1, which scales as the observing time span t−13/6obs. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models. Copyright © 2022, The Authors. All rights reserved.

关键词： Pulsars

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Astrometry of three near Earth asteroids with the Lijiang 2.4 m telescope

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Research in Astronomy and Astrophysics 2015年第3期15卷 435-442页

作者： Xi-Liang Zhang Yong Yu Xue-Li Wang Chuan-Jun Wang Liang Chang Yu-Feng Fan Zheng-Hong Tang Yunnan Observatories Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Shanghai Astronomical Observatory Chinese Academy of Sciences

Under the framework of observational campaigns organized by the GAIA Follow Up Network for Solar System objects, three near Earth asteroids, 367943 Duende, 99942 Apophis and 2013 TV135, were observed with the Lijiang 2.4m telescope administered by Yunnan Observatories. The software package PRISM was used to calibrate the CCD fields and measure the positions of 99942 Apophis and 2013 TV135, and our own software was used for 367943 Duende. A comparison of the results show that the ephemerides of INPOP10a and JPL are consistent for 99942 Apophis and 2013 TV135, however, they are quite inconsistent for 367943 Duende. Moreover, we have found that differences between the mean values in the ephemerides of INPOP10a and JPL are about 72＂ and -199＂ in right ascension and declination respectively for 367943 Duende. Moreover, the ephemeris published by JPL is reliable in terms of the mean observed-minus-calculated （O - C） residuals in right ascension and declination of about 2.72＂ and 1.49＂ respectively.

关键词： astrometry -- near Earth objects -- astrometric observation --ephemerides

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A new mechanism of long-term period variations for W UMa-type contact binaries

arXiv

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arXiv 2017年

作者： Liu, L. Qian, S.-B. Xiong, X. 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 University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

W UMa-type contact binaries belong to close binary systems whose components exactly overflow their Roche lobes and share a common convective envelope (CCE). In the last twenty years, the long-term variations of their orbital periods have been thought to depend on several mechanisms. Now, we suggest a new mechanism: CCE-dominated mechanism. The CCE-dominated mechanism is found based on our numerical result, especially at high mass ratios, that the orbital periods (P) of contact binaries change very much with their fill-out factors (f). Because f is taken as a measurement of the thickness of CCE, the physical cause for the variation of P is a mass transfer between CCE and components. Further, an f-dominated simplification model for this mechanism is introduced. According to it, P may change in a long-term oscillation way with a similar time scale of the thermal modulation, meanwhile q is decreasing slowly till the two components merge. It could be also applied to explain the presence of extremely short period, high mass ratio and deep contact binaries. Moreover, the CCE-dominated mechanism should always work due to mass transfer and mass loss both occurring via CCE. Therefor, the effect of CCE on the variations of orbital periods may have been underestimated before. Copyright © 2017, The Authors. All rights reserved.

关键词： Mass transfer

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Effects of magnetic fields on equation of state of rotating stars

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Science China(Physics,Mechanics & Astronomy) 2015年第2期58卷 109-113页

作者： NA WeiWei LIN GuiFang HUANG RunQian Department of Physics Yunnan University Department of Physics Yuxi Normal University Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences

The evolution of rotating stars with magnetic fields has been studied with focus given to the following aspects: the effects of magnetic fields on equation of state for stellar matter and the thermodynamic quantities; the effects of magnetic energy and pressure on the internal structure of stars. The differences between the structure and evolution of a 15M⊙rotating star with and without magnetic fields are discussed. Our results show that the magnetic fields have an effect on the structure and evolution of the star mainly during the central helium burning phase; and this influences the physical quantities in the stellar envelope where hydrogen and helium are partially ionized. This may influence stellar pulsation.

关键词： stars： magnetic fields stars： evolution stars： equation of state

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Erratum: 'Resolved Neutral Carbon Emission in Nearby Galaxies: [C i] Lines as Total Molecular Gas Tracers' (2019, ApJ, 880, 133)

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The Astrophysical Journal 2019年第2期883卷

作者： Qian Jiao Yinghe Zhao Nanyao Lu Yu Gao Dragan Salak Ming Zhu Zhi-Yu Zhang Xue-Jian Jiang Qinghua Tan Purple Mountain Observatory & Key Lab of Radio Astronomy Chinese Academy of Sciences (CAS) Nanjing 210033 People's Republic of China Yunnan Observatories & Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming 650011 People's Republic of China Center for Astronomical Mega-Science CAS 20A Datun Road Chaoyang District Beijing 100012 People's Republic of China China-Chile Joint Center for Astronomy (CCJCA) Camino El Observatorio 1515 Las Condes Santiago Chile National Astronomical Observatories & Key Lab of Radio Astronomy CAS Beijing 100012 People's Republic of China Purple Mountain Observatory & Key Lab of Radio Astronomy Chinese Academy of Sciences (CAS) Nanjing 210008 People's Republic of China School of Science and Technology Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 Japan Institute for Astronomy University of Edinburgh Royal Observatory Blackford Hill Edinburgh EH9 3HJ UK ESO Karl Schwarzschild Strasse 2 D-85748 Garching Munich Germany The current zip code is corrected from that in the published article.

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Light curve inversion of asteroid(585)Bilkis with Lommel-Seeliger ellipsoid method

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Research in Astronomy and Astrophysics 2016年第12期16卷 19-26页

作者： Ao Wang Xiao-Bin Wang Karri Muinonen Xianming L.Han Yi-Bo Wang Yunnan Observatories Chinese Academy of SciencesKunming 650011China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China University of Chinese Academy of Sciences Beijing 100049China Department of Physics University of HelsinkiGustaf Hallstromin katu 2aEO.Box 64FI-00014 U.HelsinkiFinland Finnish Geospatial Research Institute Geodeetinrinne 2FI-02430 MasalaFinland Department of Physics and Astronomy Butler UniversityIndianapolisIN 46208USA

The basic physical parameters of asteroids, such as spin parameters, shape and scattering parameters, can provide us with information on the formation and evolution of both the asteroids themselves and the entire solar system. In a majority of asteroids, the disk-integrated photometry measurement constitutes the primary source of the above knowledge. In the present paper, newly observed photometric data and existing data on（585） Bilkis are analyzed based on a Lommel-Seeliger ellipsoid model. With a Markov chain Monte Carlo（MCMC） method, we have determined the spin parameters（period, pole orientation）and shape（b/a, c/a） of（585） Bilkis and their uncertainties. As a result, we obtained a rotational period of 8.5738209 h with an uncertainty of 9×10^-7h, and derived a pole of（136.46°, 29.0°） in the ecliptic frame of J2000.0 with uncertainties of 0.67°and 1.1°in longitude and latitude respectively. We also derived triaxial ratios b/a and c/a of（585） Bilkis as 0.736 and 0.70 with uncertainties of 0.003 and 0.03 respectively.

关键词： asteroids -- photometric observation -- spin parameter -- shape -- MCMC method

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Comparison between the time-integrated spectrum and the peak time spectrum of gamma-ray bursts and possible implications

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Science China(Physics,Mechanics & Astronomy) 2015年第3期58卷 82-89页

作者： LYU Fen WANG YuanZhu LIANG YunFeng LIN TingTing HU YouDong LIANG EnWei Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences Guangxi University Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences

The mono-frequency peak luminosity and the corresponding photon energy of the time-integrated （L~, Eg） and peak time （L~, ffp） vfv spectra were derived for a sample of 38 redshift-known Fermi GRBs by fitting the spectra with the Band function. It was found that Ept is generally consistent with Ep, and Lp is averagely three times larger than Lp. The slope of the Lp1 -Etp relation was consistent with that of the Lps - Eps relation. The photon indices in the peak time spectrum, particularly, the index of the low energy end was, were statistically larger than that in the time-integrated spectrum. These results indicate that Lp and Ep are dominated by Lp1 and Ept, respectively. The difference of the spectral indices between the time-integrated and peak time spectra may be because of the overlap effect of a series of time-resolved spectra within a GRB. Our simulations, which were based on the observed spectral evolution and correlation between the energy flux and the peak energy within individual GRBs support our speculations. The Lt - Et, relation may be less contaminated by the overla!a effect, and it would may be an intrinsic feature of radiation ohvsics.

关键词： γ-ray sources γ-ray bursts gamma-rays： astronomical observations

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Optical quasi-periodic oscillation of the BL Lacertae object S5 0716+714 during the faint state

arXiv

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arXiv 2017年

作者： Hong, Shanwei Xiong, Dingrong Bai, Jinming Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China School of Applied Technology Lijiang Teachers College Lijiang674199 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

In order to search for the evidence of quasi-periodic oscillation (QPO) in blazar, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For I band on March 19 2010 with low variability amplitude and low flux level, the same quasi-periodic oscillation 50 minutes with 99% significance levels is confirmed by ZDCF method, Lomb-Scargle method, REDFIT and fitting sinusoidal curves. The observed QPO is likely to be explained by accretion disk variability. If the observed QPO indicates an innermost stable orbital period from the accretion disk, the QPO 50 min corresponds to a black hole mass of 5.03×106M☉ for a non-rotating Schwarzschild black hole and 3.2 × 107M☉ for a maximally rotating Kerr black hole. Copyright © 2017, The Authors. All rights reserved.

关键词： Gravitation

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OPTICAL OBSERVATIONS OF THE YOUNG TYPE Ic SUPERNOVA SN 2014L IN M99

arXiv

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arXiv 2018年

作者： Zhang, Jujia Wang, Xiaofeng Vinkó, József Wheeler, J. Craig Chang, Liang Yang, Yi Wang, Lifan Zhai, Qian Rui, Liming Mo, Jun Zhang, Tianmeng Zhang, Yu Wang, Jianguo Mao, Jirong Wang, Chuanjun Yi, Weimin Xin, Yuxin Li, Wenxiong Lun, Baoli Lu, Kaixing Sai, Hanna Zheng, Xiangming Zhang, Xiliang Zhou, Xu Bai, Jinming Chinese Academy of Sciences Kunming650216 China George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University College StationTX77843 United States 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 20A Datun Road Chaoyang District Beijing100012 China Tsinghua University Beijing100084 China Konkoly Observatory Research Centre for Astronomy and Earth Sciences Konkoly Thege ut 15-17 Budapest1121 Hungary Department of Optics and Quantum Electronics University of Szeged Dómtér 9 SzegedH-6720 Hungary Department of Astronomy University of Texas at Austin AustinTX78712-1205 United States Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel Chinese Academy of Sciences Beijing100012 China Chinese Academy of Sciences Urumqi830011 China

We present optical spectroscopic and photometric observations of the nearby type Ic supernova (SN Ic) SN 2014L. This SN was discovered by the Tsinghua-NAOC Transient Survey (TNTS) in the nearby type-Sc spiral galaxy M99 (NGC 4254). Fitting to the early-time light curve indicates that SN 2014L was detected at only a few hours after the shock breakout, and it reached a peak brightness of MV = −17.73 ± 0.28 mag (L = [2.06 ± 0.50] × 1042 erg s−1) approximately 13 days later. SN 2014L shows a close resemblance to SN 2007gr in the photometric evolution, while it shows stronger absorption features of intermediate-mass elements (especially Ca ii) in the early-time spectra. Based on simple modeling of the observed light curves, we derived the mass of synthesized 56Ni as MNi = 0.075 ±0.025 M1577, and the mass and total energy of the ejecta as Mej=1.00±0.20M1577 and Eej = 1.45 ±0.25 foe, respectively. Given these typical explosion parameters, the early detection, and the extensive observations, we suggest that SN 2014L could be a template sample for the investigation of SNe Ic. Copyright © 2018, The Authors. All rights reserved.

关键词： Photometry

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Multi-color optical monitoring of the BL Lacertae object S5 0716+714 during the 2012 outburst

arXiv

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arXiv 2017年

作者： Hong, Shanwei Xiong, Dingrong Bai, Jinming Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Department of Mathematics and Computer Science Lijiang Teachers College Lijiang674199 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

We have monitored the BL Lacertae object S5 0716+714 in the optical bands during 2012 January and February with long time spans on intraday timescales (>5 hr) and high time resolutions. During this monitoring period, the object shows violent flaring activity both in short and intraday timescales. The object has high value of duty cycle. The light curves detected as intraday variability (IDV) show variability of various shapes. The variability amplitude is from 12.81 per cent to 33.22 per cent, and the average value 19.92 ± 5.87 per cent. The overall magnitude variabilities are ΔB = 1m.24, ΔV = 1m.42, ΔR = 1m.3, ΔI = 1m.23 respectively. During the observations, the average change rate is = 0.035 ± 0.009 Mag/h during the ascent and = 0.035 ± 0.014 Mag/h during the descent. However, different cases are found on certain nights. There are good inter-bands correlations but not significant time lags for intraday and short timescales. The results of the autocorrelation function show that the variability timescales range from 0.054 day to 0.134 day. Most of nights show bluer when brighter (BWB) chromatic trend;a weak redder with brighter (RWB) trend is found;a few nights show no correlations between magnitude and color index. The BWB trend appears in the short timescales. During the flare the spectral index exhibits a clockwise loop for inter-nights. A shock-in-jet model and the shock wave propagating along a helical path are likely to explain the variability and color index variability. Copyright © 2017, The Authors. All rights reserved.

关键词： Shock waves

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