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Is BZB J1450+5201 the most distant gamma-ray BL Lacertae object?

Research in Astronomy and Astrophysics 2015年第3期15卷 313-326页

作者： Neng-Hui Liao Jin-Ming Bai Jian-Guo Wang Hong-Tao Liu Jiu-Jia Zhang Ning Jiang Zun-Li Yuan Liang Chen Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory for Research in Galaxies and Cosmology University of Science and Technology of China Chinese Academy of Sciences Department of Astronomy University of Science and Technology of China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of Sciences

BL Lacertae （BL Lac） objects at high redshifts （z ≥ 2） are rarely detected. Through careful analysis of its Sloan Digital Sky Survey spectrum, BZB J1450＋5201 is confirmed to be a high-z BL Lac object with z ≥ 2.471 by identifying the Lyα 1216 and CIV 1548/1550 absorption lines. This indicates that BZB J1450＋5201 is the most distant BL Lac object discovered to date. Careful analysis of the five-year Fermi-LAT data of 2FGL J1451.0＋5159 shows that its γ-ray emission is robust with a confidence level of 6.2σ at 1-3 GeV and 6.7σ at 3-10 GeV. This analysis with the five-year data overcomes confusion with its bright neighbor, which is a problem when analyzing the two-year data. In addition, 2FGL J 1451.0＋5159 is confirmed to be associated with BZB J1450＋5201 using the five-year data. The analysis of multiwavelength data, from radio to γ-ray energies, indicates that BZB J1450＋5201 is an intermediate synchrotron peaked （ISP） source. Its multiwavelength properties are consistent with distributions of other ISP sources at lower redshifts in the second Fermi-LAT AGN catalog. The pure synchrotron self-Compton （SSC） model seems to be disfavored, but the scattering of weak external emission plus the SSC process can provide a satisfactory description of the broadband emission.

关键词： galaxies active -- BL Lacertae objects individual （BZB J1450＋5201）-- gamma rays galaxies -- radiation mechanisms non-thermal

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Quiescent photometric modulations of two low-inclination cataclysmic variables KZ Gem and TW Vir

arXiv

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arXiv 2017年

作者： Dai, Zhibin Szkody, Paula Taani, Ali Garnavich, Peter M. Kennedy, Mark 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 Washington SeattleWA98195 United States Applied Sciences Department Aqaba University College Al-Balqa' Applied University P.O. Box 1199 Aqaba77110 Jordan University of Notre Dame Notre DameIN46556 United States Department of Physics University College Cork Cork Ireland

Aims. The quiescent periodic photometric modulations of two low-inclination cataclysmic variables observed in Kepler K2 Campaigns 0 and 1, KZ Gem and TW Vir, are investigated. Methods. A phase-correcting method was successfully used to detect the orbital modulations of KZ Gem and TW Vir and improve their orbital periods. The light curve morphologies of both CVs were further analyzed by defining flux ratios and creating colormaps. Results. KZ Gem shows ellipsoidal modulations with an orbital period of 0.22242(1) day, twice the period listed in the updated RK catalogue (Edition 7.24). With this newly determined period, KZ Gem is no longer a CV in the period gap, but a long-period CV. A part of the quiescent light curve of TW Vir that had the highest stability was used to deduce its improved orbital period of 0.182682(3) day. The flat patterns shown in the colormaps of the flux ratios for KZ Gem demonstrate the stability of their orbital modulations, while TW Vir show variable orbital modulations during the K2 datasets. In TW Vir, the single versus double-peaked nature of the quiescent orbital variations before and after superoutburst may be related to the effect of the superoutburst on the accretion disk. Copyright © 2017, The Authors. All rights reserved.

关键词： Photometry

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Studies for slowly rotating asteroids (168) Sibylla and (346) Hermentaria

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Proceedings of the International Astronomical Union 2016年第S318期10卷 185-192页

作者： Wang, Xiaobin Muinonen, Karri Han, Xianming L. Kwok, Chi-Tai Yunnan Observatories CAS P.O. Box 110 Kunming Yunnan Province 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming 650011 China Department of Physics University of Helsinki Gustaf Hällströmin katu 2a P.O. Box 64 U. Helsinki FI-00014 Finland Finnish Geospatial Research Institute Geodeetinrinne 2 Masala FI-02430 Finland Department of Physics and Astronomy Butler University Indianapolis IN United States Ho Koon Nature Education Cum Astronomical Centre Sik Sik Yuen Hong Kong

Studies for spin parameters and shapes of asteroids provide us with important information about the interior structure of asteroids and the physical processes they have undergone. A large sample of basic physical parameters can help us also understand the evolution of asteroids. There is scarce information for slowly-rotating larger asteroids because more effort is required for observing them. Because of this, we have established an international collaboration to study slowly-rotating asteroids. As the first step of this project, we have observed asteroids (168) Sibylla and (346) Hermentaria in 2014 and 2015 using several telescopes located in China, Chile, and U.S.A. Combining previous photometric data with our new data, we have performed preliminary analyses and obtained spin parameters and shapes with their uncertainties for these two slowly-rotating asteroids for the first time, using the convex inversion method and the virtual photometry Monte Carlo method. A pair of pole solutions for (168) Sibylla are found around (4.3°, 53.5°) and (183.5°, 52.6°) with a period of 47.0000 h. We have found that the shape of Sibylla resembles an oblate spheroid. For (346) Hermentaria, we have also found a pair of pole solutions around (134.5°, 16.7°) and (321.5°, 14.5°) with comparable rms-values with a spin period of about 17.79000 h, and a shape resembling a prolate spheroid. Copyright © 2016 International Astronomical Union.

关键词： asteroids methods: data analysis methods: numerical methods: statistical Minor planets radiative transfer scattering solar system: general techniques: photometric

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Search for Exoplanets around Northern Circumpolar Stars II. The Detection of Radial Velocity Variations in M Giant Stars HD 36384, HD 52030, and HD 208742

arXiv

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arXiv 2017年

作者： Lee, Byeong-Cheol Jeong, Gwanghui Park, Myeong-Gu Han, Inwoo Mkrtichian, David E. Hatzes, Artie P. Gu, Shenghong Bai, Jinming Lee, Sang-Min Oh, Hyeong-Il Kim, Kang-Min Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-gu Daejeon305-348 Korea Republic of Astronomy and Space Science Major Korea University of Science and Technology Gajeong-ro Yuseong-gu Daejeon305-333 Korea Republic of Department of Astronomy and Atmospheric Sciences Kyungpook National University Daegu702-701 Korea Republic of National Astronomical Research Institute of Thailand Chiang Mai50200 Thailand Crimean Astrophysical Observatory Taras Shevchenko National University of Kyiv Nauchny Crimea98409 Ukraine Sternwarte 5 Tautenburg07778 Germany Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

We present the detection of long-period RV variations in HD 36384, HD 52030, and HD 208742 by using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) for the precise radial velocity (RV) survey of about 200 northern circumpolar stars. Analyses of RV data, chromospheric activity indicators, and bisector variations spanning about five years suggest that the RV variations are compatible with planet or brown dwarf companions in Keplerian motion. However, HD 36384 shows photometric variations with a period very close to that of RV variations as well as amplitude variations in the weighted wavelet Z-transform (WWZ) analysis, which argues that the RV variations in HD 36384 are from the stellar pulsations. Assuming that the companion hypothesis is correct, HD 52030 hosts a companion with minimum mass 13.3 MJup orbiting in 484 days at a distance of 1.2 AU. HD 208742 hosts a companion of Copyright © 2017, The Authors. All rights reserved.

关键词： Orbits

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Monitor variability of millimeter lines in IRC+10216

arXiv

引用

arXiv 2017年

作者： He, J.H. -Trung, Dinh-V Hasegawa, T.I. Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for Astronomy Camino El Observatorio #1515 Las Condes Santiago Chile 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 Institute of Physics Vietnam Academy of Science and Technology 10 DaoTan BaDinh Hanoi Viet Nam Academia Sinica Astronomy and Astrophysics AS/NTU. No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan

A single dish monitoring of millimeter maser lines SiS J=14-13 and HCNv2 = 1f J=3-2 and several other rotational lines is reported for the archetypal carbon star IRC+10216. Relative line strength variations of 5%∼30% are found for eight molecular line features with respect to selected reference lines. Definite line-shape variation is found in limited velocity intervals of the SiS and HCN line profiles. The asymmetrical line profiles of the two lines are mainly due to the varying components. Their dominant varying components of the line profiles have similar periods and phases as the IR light variation, although both quantities show some degree of velocity dependence;there is also variability asymmetry between the blue and red line wings of both lines. Combining the velocities and amplitudes with a wind velocity model, we suggest that the line profile variations are due to SiS and HCN masing lines emanating from the wind acceleration zone. The possible link of the variabilities to thermal, dynamical and/or chemical processes within or under this region is also discussed. Copyright © 2017, The Authors. All rights reserved.

关键词： Masers

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Hubble Space Telescope Ultraviolet Light Curves Reveal Interesting Properties of CC Sculptoris and RZ Leonis

arXiv

引用

arXiv 2017年

作者： Szkody, Paula Mukadam, Anjum S. Toloza, Odette Gänsicke, Boris T. Dai, Zhibin Pala, Anna F. Waagen, Elizabeth O. Godon, Patrick Sion, Edward M. Department of Astronomy University of Washington Box 351580 SeattleWA98195 United States Apache Point Observatory Astrophysical Research Consortium Department of Physics University of Warwick CoventryCV4 7AL United Kingdom 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 AAVSO 48 Bay State Rd CambridgeMA02138 Department of Astrophysics and Planetary Science Villanova University VillanovaPA19085 United States

Time-tag ultraviolet data obtained on the Hubble Space Telescope in 2013 reveal interesting variability related to the white dwarf spin in the two cataclysmic variables RZ Leo and CC Scl. RZ Leo shows a period at 220 s and its harmonic at 110 s, thus identifying it as a likely Intermediate Polar (IP). The spin signal is not visible in a short single night of ground based data in 2016, but the shorter exposures in that dataset indicate a possible partial eclipse. The much larger UV amplitude of the spin signal in the known IP CC Scl allows the spin of 389 s, previously only seen at outburst, to be visible at quiescence. Spectra created from the peaks and troughs of the spin times indicate a hotter temperature of several thousand degrees during the peak phases, with multiple components contributing to the UV light. Copyright © 2017, The Authors. All rights reserved.

关键词： White dwarfs

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The Effect of Metallicity on the Dynamical evolution of A Globular Cluster

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Chinese Astronomy and Astrophysics 2015年第1期39卷 1-15页

作者： Zhuang, Yu-Long Zhang, Feng-Hui Yunnan Astronomical 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 University of Chinese Academy of Sciences Beijing 100049 China

The dynamical process and stellar evolution, as well as their mutual interaction will make important influences on the evolution of a globular cluster. As the matallicity may affect the track of stellar evolution, the associated variation of stellar mass loss rate will make influence on the dynamical process of the globular cluster as well. A series of N-body simulations are performed to study the effects of matallicity on the mass loss rate and radius of a globular cluster, and the reasons are analyzed. At the same time, the effects of large-mass stars and the cluster's initial number density distribution are also studied. In the simulations, the adopted initial number of member stars in the globular cluster model is N =50000, they move in the Galaxy-like gravitational potential, and their evolutions are also taken into consideration. The results indicate that because the low-matallicity stars have a faster evolutionary timescale, so in the early period the metal-poor globular cluster will have a higher mass loss, but at the same time its core collapse will be obviously delayed in time, hence after the core collapse its mass loss will be overtaken by the metal-rich globular cluster. In addition, as the evolution of large-mass star causes a larger mass loss, hence the existence of large-mass stars will make the matallicity even significantly influence on the early period expansion of the globular cluster, and the succeeding process of core collapse, besides, the influence of the cluster's initial number density distribution is also not negligible. © 2015.

关键词： evolution-methods General-stars Globular clusters Numerical

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The Double Blue Straggler Sequence in NGC 2173: A Field Contamination Artifact?

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Research Notes of the AAS 2018年第4期2卷

作者： Chengyuan Li Licai Deng Richard de Grijs Dengkai Jiang Yu Xin Department of Physics and Astronomy Macquarie University Balaclava Road Sydney NSW 2109 Australia Department of Astronomy China West Normal University Nanchong 637002 People's Republic of China School of Astronomy and Space Science University of the Chinese Academy of Sciences 20A Datun Road Beijing 100012 People's Republic of China International Space Science Institute—Beijing 1 Nanertiao Zhongguancun Beijing 100190 People's Republic of China Yunnan Observatories Chinese Academy of Sciences Kunming 650216 People's Republic of China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 People's Republic of China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing 100012 People's Republic of China

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Deep imaging of the HCG 95 field. ***-diffuse galaxies

arXiv

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arXiv 2017年

作者： Shi, Dong Dong Zheng, Xian Zhong Zhao, Hai Bin Pan, Zhi Zheng Li, Bin Zou, Hu Zhou, Xu Guo, Ke Xin An, Fang Xia Li, Yu Bin Purple Mountain Observatory Chinese Academy of Sciences 2 West Beijing Road Nanjing210008 China School of Astronomy and Space Sciences University of Science and Technology of China Hefei230026 China Chinese Academy of Science South America Center for Astronomy China-Chile Joint Center for Astronomy Camino EI Observatorio #1515 Las Condes Santiago Chile Key Laboratory of Planetary Sciences Chinese Academy of Sciences 2 West Beijing Road Nanjing210008 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 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

We present a detection of 89 candidates of ultra-diffuse galaxies (UDGs) in a 4.9 degree2 field centered on the Hickson Compact Group 95 (HCG95) using deep g- and r-band images taken with the Chinese Near Object Survey Telescope. This field contains one rich galaxy cluster (Abell 2588 at z=0.199) and two poor clusters (Pegasus I at z=0.013 and Pegasus II at z=0.040). The 89 candidates are likely associated with the two poor clusters, giving about 50 - 60 true UDGs with a half-light radius re> 1.5 kpc and a central surface brightness μ(g, 0) > 24.0mag arcsec-2. Deep z'-band images are available for 84 of the 89 galaxies from the Dark Energy Camera Legacy Survey (DECaLS), confirming that these galaxies have an extremely low central surface brightness. Moreover, our UDG candidates are spread over a wide range in g -r color, and ~26% are as blue as normal star-forming galaxies, which is suggestive of young UDGs that are still in formation. Interestingly, we find that one UDG linked with HCG95 is a gas-rich galaxy with HI mass 1.1×109Modetected by the Very Large Array, and has a stellar mass of M∗ ~ 1.8 × 108Mo. This indicates that UDGs at least partially overlap with the population of nearly dark galaxies found in deep HI surveys. Our results show that the high abundance of blue UDGs in the HCG95 field is favored by the environment of poor galaxy clusters residing in HI-rich large-scale structures. Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

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The long-lived Type IIn SN 2015da: Infrared echoes and strong interaction within an extended massive shell

arXiv

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arXiv 2019年

作者： Tartaglia, L. Pastorello, A. Sollerman, J. Fransson, C. Mattila, S. Fraser, M. Taddia, F. Tomasella, L. Turatto, M. Morales-Garoffolo, A. Elias-Rosa, N. Lundqvist, P. Harmanen, J. Reynolds, T. Cappellaro, E. Barbarino, C. Nyholm, A. Kool, E. Ofek, E. Gao, X. Jin, Z. Tan, H. Sand, D.J. Ciabattari, F. Wang, X. Zhang, J. Huang, F. Li, W. Mo, J. Rui, L. Xiang, D. Zhang, T. Hosseinzadeh, G. Howell, D.A. McCully, C. Valenti, S. Benetti, S. Callis, E. Carracedo, A.S. Fremling, C. Kangas, T. Rubin, A. Somero, A. Terreran, G. Department of Astronomy and the Oskar Klein Centre Stockholm University AlbaNova Roslagstullsbacken 21 StockholmSE 114 21 Sweden INAF - Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 Padova35122 Italy Tuorla Observatory Department of Physics and Astronomy FI 20014 University of Turku Finland School of Physics O’Brien Centre for Science North University College Dublin Belfield Dublin 4 Ireland Department of Applied Physics Universidad de Cádiz campus of Puerto Real Cádiz11510 Spain Campus UAB Camí de Can Magrans s/n Cerdanyola del Vallès Barcelona08193 Spain c/Gran Capità 2 – 4 Edif. Nexus 201 Barcelona08034 Spain Benoziyo Center for Astrophysics and the Helen Kimmel center for planetary science Weizmann Institute of Science Rehovot76100 Israel Xinjiang Astronomical Observatory 150 Science 1–Street Urumqi Xinjiang830011 China Xingming Observatory Mountain Nanshan Urumqi Xinjiang830011 China Graduate Institute of Astronomy National Central University 300 Zhongda Rd. Zhongli District Taoyuan City32001 Taiwan Department of Astronomy/Steward Observatory 933 North Cherry Avenue Rm. N204 TucsonAZ85721-0065 United States Osservatorio Astronomico di Monte Agliale Via Cune Motrone Borgo a Mozzano Lucca55023 Italy Physics Department and Tsinghua Center for Astrophysics Tsinghua University Beijing100084 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 Department of Astronomy School of Physics and Astronomy Shanghai Jiaotong Univeristy Shanghai200240 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing10101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138-1516 United States Las

We report the results of the first ∼ 4 years of spectroscopic and photometric monitoring of the Type IIn supernova SN 2015da (aka PSN J13522411+3941286, or iPTF16tu). The supernova exploded in the nearby spiral galaxy NGC 5337, in a relatively highly extinguished environment. SN 2015da shows prominent Balmer lines in emission with narrow components at all times and a slow rise to maximum. In addition, early observations performed by amateur astronomers give a very well–constrained explosion epoch. The observables are consistent with continuous interaction between the supernova ejecta and a dense and extended H–rich circumstellar medium. This is likely the mechanism powering the light curve, as confirmed by the analysis of the pseudo bolometric light curve, which gives a total radiated energy & 1051 erg. Modeling the light curve in the context of a supernova shock breakout through a dense circumstellar medium allowed us to infer the mass of the pre–existing gas to be > 8.2 M, with an extreme mass–loss rate for the progenitor star ' 0.4 − 0.8 M yr−1, suggesting that most of the circumstellar gas was produced during multiple eruptive events. Near– and mid–infrared observations reveal a flux excess in these domains, similar to those observed in SN 2010jl and other interacting transients, likely due to pre–existing radiatively–heated dust surrounding the supernova. By modeling the infrared excess, we infer a mass & 0.4 × 10−3 M for the dust. Copyright © 2019, The Authors. All rights reserved.

关键词： Supernovae

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