检索结果-内蒙古大学图书馆

SN 2014J in M82: New insights on the spectral diversity of type Ia supernovae

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Zhang, Kaicheng Wang, Xiaofeng Zhang, JuJia Zhang, Tianmeng Benetti, S. Elias-Rosa, N. Huang, Fang Lin, Han Li, Linyi Li, Wenxiong Ochner, P. Pastorello, A. Rui, Liming Tartaglia, L. Tomasella, L. Siviero, A. Munari, U. Terreran, G. Song, Hao Taubenberger, S. Wheeler, J. Craig Xiang, Danfeng Zhao, Xulin Li, Hongbin Bai, Jinming Jiang, Xiaojun Shi, Jianrong Wu, Zhenyu Tsinghua University Beijing100084 China Department of Astronomy University of Texas at Austin AustinTX78712-1205 United States Yunnan Observatories Chinese Academy of Sciences Kunming650216 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 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory of Optical Astronomy National Astronomical Observatory of China Chinese Academy of Sciences Beijing100012 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China INAF - Osservatorio Astronomico di Padova vicolo dell’Osservatorio 5 PadovaI-35122 Italy Department of Astronomy School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Dipartimento di Fisica e Astronomia Università di Padova via Marzolo 8 PadovaI-35131 Italy Department of Astronomy and The Oskar Klein Centre AlbaNova University Center Stockholm University StockholmSE-106 91 Sweden Department of Physics and Astronomy Northwestern Unive European Southern Observatory Karl-Schwarzschild-Str. 2 Garching85748 Germany Max-Planck-Institut für Astrophysik Karl-Schwarzschild-Str. 1 Garching85748 Germany School of Science Tianjin University of Technology Tianjin300384 China

We present extensive spectroscopic observations for one of the closest type Ia supernovae (SNe Ia), SN 2014J discovered in M82, ranging from 10.4 days before to 473.2 days after B-band maximum light. The diffuse interstellar band (DIB) features detected in a high-resolution spectrum allow an estimate of line-of-sight extinction as Av ∼1.9±0.6 mag. Spectroscopically, SN 2014J can be put into the high-velocity (HV) subgroup in Wang’s classification with a velocity of Si ii λ 6355 at maximum light of v0 = 1.22±0.01×104 km s−1, but has a low velocity gradient (LVG, following Benetti’s classification) of vÛ = 41±2 km s−1 day−1, which is inconsistent with the trend that HV SNe Ia generally have larger velocity gradients. We find that the HV SNe Ia with LVGs tend to have relatively stronger Si iii (at ∼4400 Å) absorptions in early spectra, larger ratios of S ii λ 5468 to S ii λ 5640, and weaker Si ii 5972 absorptions compared to their counterparts with similar velocities but high velocity gradients. This shows that the HV+LVG subgroup of SNe Ia may have intrinsically higher photospheric temperature, which indicates that their progenitors may experience more complete burning in the explosions relative to the typical HV SNe Ia. Copyright © 2018, The Authors. All rights reserved.

关键词： Supernovae

GeV detection of HESS J0632+057

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Li, Jian Torres, Diego F. Cheng, K.-S. de Oña Wilhelmi, Emma Kretschmar, Peter Hou, Xian Takata, Jumpei Campus UAB Carrer de Magrans s/n Barcelona08193 Spain BarcelonaE-08010 Spain Department of Physics University of Hong Kong Pokfulam Road Hong Kong Hong Kong Spain 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 School of Physics Huazhong University of Science and Technology Wuhan430074 China

HESS J0632+057 is the only gamma-ray binary that has been detected at TeV energies, but not at GeV energies yet. Based on nearly nine years of Fermi Large Area Telescope (LAT) Pass 8 data, we report here on a deep search for the gamma-ray emission from HESS J0632+057 in the 0.1–300 GeV energy range. We find a previously unknown gamma-ray source, Fermi J0632.6+0548, spatially coincident with HESS J0632+057. The measured flux of Fermi J0632.6+0548 is consistent with the previous flux upper limit on HESS J0632+057 and shows variability that can be related to the HESS J0632+057 orbital phase. We propose that Fermi J0632.6+0548 is the GeV counterpart of HESS J0632+057. Considering the Very High Energy (VHE) spectrum of HESS J0632+057, a possible spectral turnover above 10 GeV may exist in Fermi J0632.6+0548, as appears to be common in other established gamma-ray binaries. Copyright © 2017, The Authors. All rights reserved.

关键词： Gamma rays

Long-term photometric behavior of the eclipsing cataclysmic variable V729 Sgr

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Zhongtao, Han Shengbang, Qian Fernández, Lajús E. Irina, Voloshina Liying, Zhu Yunnan Observatories Chinese Academy of Sciences PO Box 110 Kunming650011 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences PO Box 110 Kunming650011 China Graduate University of the Chinese Academy of Sciences Yuquan Road 19 Sijingshang Block Beijing City100049 China Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque s/n La Plata Pcia. Bs. As1900 Argentina Argentina Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow119992 Russia

We present the analysis results of an eclipsing cataclysmic variable (CV) V729 Sgr, based on our observations and AAVSO data. Some outburst parameters were determined such as outburst amplitude (An) and recurrence time (Tn), and then the relationship between An and Tn is discussed. A cursory examination for the long-term light curves reveals that there are small-amplitude outbursts and dips present, which is similar to the behaviors seen in some nova-like CVs (NLs). More detailed inspection suggests that the outbursts in V729 Sgr may be Type A (outside-in) with a rise time ∼ 1.76 d. Further analysis also shows that V729 Sgr is an intermediate between dwarf nova and NLs, and we constrain its mass transfer rate to 1.59 × 10−9 2 −9M☉yr−1 by combining the theory for Z Cam type stars with observations. Moreover, the rapid oscillations in V729 Sgr were detected and analyzed for the first time. Our results indicate that the oscillation at ∼ 25.5 s is a true DNO, being associated with the accretion events. The classification of the oscillations at ∼ 136 and 154 s as lpDNOs is based on the relation between PlpDNOs and PDNOs. Meanwhile, the QPOs at the period of hundreds of seconds are also detected. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

A new stellar outburst associated with the magnetic activities of the k-type dwarf in a white-dwarf binary

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Qian, S.-B. Han, Z.-T. Zhang, B. Zejda, M. Michel, R. Zhu, L.-Y. Zhao, E.-G. Liao, W.-P. Tian, X.-M. Wang, Z.-H. P.O. Box 110 Kunming650011 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O. Box 110 Kunming650011 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# Sijingshang Block Beijing100049 China Department of Theoretical Physics and Astrophysics Masaryk University Kotlářská 2 BrnoCZ-611 37 Czech Republic Instituto de Astronomía Universidad Nacional Autónoma de Méexico Ensenada Baja California Mexico

1SWASP J162117.36+441254.2 was originally classified as an EW-type binary with a period of 0.20785 days. However, it was detected to have undergone a stellar outburst on June 3, 2016. Although the system was latter classified as a cataclysmic variable (CV) and the event was attributed as a dwarf-nova outburst, the physical reason is still unknown. This binary has been monitored photometrically since April 19, 2016 and many light curves were obtained before, during and after the outburst. Those light and color curves observed before the outburst indicate that the system is a special CV. The white dwarf is not accreting material from the secondary and there are no accretion disks surrounding the white dwarf. By comparing the light curves obtained from April 19 to September 14, 2016, it was found that magnetic activity of the secondary is associated with the outburst. We show strong evidence that the L1region on the secondary was heavily spotted before and after the outburst and thus quench the mass transfer, while the outburst is produced by a sudden mass accretion of the white dwarf. These results suggest that J162117 is a good astrophysical laboratory to study stellar magnetic activity and its influences on CV mass transfer and mass accretion. Copyright © 2017, The Authors. All rights reserved.

关键词： White dwarfs

Alma observation of ngc5135: The circumnuclear co(6-5) and dust continuum emission at 45 parsec resolution

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Cao, Tianwen Lu, Nanyao Xu, C. Kevin Zhao, Yinghe Kalari, Venu Madhav Gao, Yu Charmandaris, Vassilis Santos, Tanio Diaz Van Der Werf, Paul Cao, Chen Wu, Hong Inami, Hanae Evans, Aaron Chinese Academy of Sciences South America Center for Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Instituto de Astrofisica Pontificia Universidad Católica de Chile Av.Vicuña Mackenna 4860 Macul Santiago7820436 Chile Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Center for Astronomical Mega-Science CAS 20A Datun Road Chaoyang District Beijing100012 China Departamento de Astronoma Universidad de Chile Casilla 36-D Correo Central Santiago Chile Purple Mountain Observatory Key Lab of Radio Astronomy 8 YuanHua Road Nanjing210034 China Department of Physics University of Crete HeraklionGR-71003 Greece IAASARS National Observatory of Athens Pen-teliGR-15236 Greece Ncleo de Astronoma de la Facultad DeIngeniera Universidad Diego Portales Av. Ejercito Libertador 441 Santiago Chile Leiden Observatory Leiden University P.O. Box 9513 RA Leiden2300 Netherlands School of Space Science and Physics Shandong University Weihai Shandong264209 China Shandong Provincial Key Laboratory of Optical Astronomy Solar-Terrestrial Environment Weihai Shandong264209 China UMR 5574 Saint-Genis-Laval69230 France Department of Astronomy University of Virginia CharlottesvilleVA22903-2325 United States National Radio Astronomy Observatory 520 Edgemont Road CharlottesvilleVA22903-2475 United States

We present high-resolution (0.17'' × 0.14'') Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO(6{5) line, and 435 μm dust continuum emission within a ∼9"× 9" area centered on the nucleus of the galaxy NGC5135. NGC5135 is a well-studied luminous infrared galaxy that also harbors a Compton-thick active galactic nucleus (AGN). At the achieved resolution of 48 × 40 pc, the CO(6{5) and dust emissions are resolved into gas 'clumps" along the symmetrical dust lanes associated with the inner stellar bar. The clumps have radii between ∼45-180 pc and CO(6-5) line widths of ∼60-88 km s-1. The CO(6-5) to dust continuum ux ratios vary among the clumps and show an increasing trend with the [Fe ii]/Br-γ ratios, which we interpret as evidence for supernovadriven shocked gas providing a significant contribution to the CO(6-5) emission. The central AGN is undetected in continuum, nor in CO (6-5) if its line velocity width is no less than ∼40 km s-1. We estimate that the AGN contributes at most 1% of the integrated CO(6-5) flux of 512 ± 24 Jykm s-1within the ALMA field of view, which in turn accounts for ∼32% of the CO(6-5) flux of the whole galaxy. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

The young and nearby normal type ia supernova 2018gv: UV-optical observations and the earliest spectropolarimetry

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Yang, Yi Hoeflich, Peter Baade, Dietrich Maund, Justyn R. Wang, Lifan Brown, Peter J. Stevance, Heloise F. Arcavi, Iair Burke, Jamison Cikota, Aleksandar Clocchiatti, Alejandro Gal-Yam, Avishay Graham, Melissa L. Hiramatsu, Daichi Hosseinzadeh, Griffin Howell, D. Andrew Jha, Saurabh W. McCully, Curtis Patat, Ferdinando Sand, David J. Schulze, Steve Spyromilio, Jason Valenti, Stefano Vinkao, Jozsef Wang, Xiaofeng Wheeler, J. Craig Yaron, Ofer Zhang, Jujia Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel Department of Physics Florida State University TallahasseeFL32306-4350 United States European Southern Observatory Karl-Schwarzschild-Str. 2 Garching b. Munchen85748 Germany Department of Physics and Astronomy University of Sheffield Hicks Building Hounsfield Road SheffieldS37RH United Kingdom George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University 4242 TAMU College StationTX77843 United States Purple Mountain Observatory Chinese Academy of Sciences Nanjing210008 China Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Physics Division Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States Casilla 306 Santiago 22 Department of Astronomy University of Washington Box 351580 U.W. SeattleWA98195 United States Harvard-Smithsonian Center for Astrophysics 60 Garden Street CambridgeMA02138 United States Department of Physics and Astronomy Rutgers State University of New Jersey 136 Frelinghuysen Rd. PiscatawayNJ08854 United States Center for Computational Astrophysics Flatiron Institute 162 5th Avenue New YorkNY10010 United States Steward Observatory University of Arizona 933 North Cherry Avenue Rm. N204 TucsonAZ85721-0065 United States Department of Physics University of California DavisCA95616 United States Konkoly Observatory MTA CSFK Konkoly Thege M. ut 15-17 Budapest1121 Hungary Department of Optics & Quantum Electronics University of Szeged Dom ter 9 Szeged6720 Hungary Department of Astronomy University of Texas at Austin AustinTX78712 United States Tsinghua University Beijing100084 Chinese Academy of Sciences

The non-detection of companion stars in Type Ia supernova (SN) progenitor systems lends support to the notion of double-degenerate (DD) systems and explosions triggered by the merging of two white dwarfs. This very asymmetric process should lead to a conspicuous polarimetric signature. By contrast, observations consistently find very low continuum polarization as the signatures from the explosion process largely dominate over the pre-explosion configuration within several days. Critical information about the interaction of the ejecta with a companion and any circumstellar matter is encoded in the early polarization spectra. In this study, we obtain spectropolarimetry of SN2018gv with the ESO Very Large Telescope at .13.6 days relative to the *** maximum light, or 5 days after the estimated explosion the earliest spectropolarimetric observations to date of any Type Ia SN. These early observations still show a low continuum polarization (-0.2%) and moderate line polarization (0.30 0.04% for the prominent Si II 6355 feature and 0.85 0.04% for the high-velocity Ca component). The high degree of spherical symmetry implied by the low line and continuum polarization at this early epoch is consistent with explosion models of delayed detonations and is inconsistent with the merger-induced explosion scenario. The dense UV and optical photometry and optical spectroscopy within the first 100 days after the maximum light indicate that SN2018gv is a normal Type Ia SN with similar spectrophotometric behavior to SN2011fe. Copyright © 2019, The Authors. All rights reserved.

关键词： Polarization

Bright mini-outburst ends the 12−year long activity of the black hole candidate swift J1753.5−0127

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Zhang, G.-B. Bernardini, F. Russell, D.M. Gelfand, J.D. Lasota, J.-P. Al Qasim, A. AlMannaei, A. Koljonen, K.I.I. Shaw, A.W. Lewis, F. Tomsick, J.A. Plotkin, R.M. Miller-Jones, J.C.A. Maitra, D. Homan, J. Charles, P.A. Kobel, P. Perez, D. Doran, R. Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China Center for Astronomical Mega-Science CAS Beijing100012 China New York University Abu Dhabi P.O. Box 129188 Abu Dhabi United Arab Emirates INAF − Osservatorio Astronomico di Roma via Frascati 33 Monteporzio Catone RomaI-00040 Italy INAF − Osservatorio Astronomico di Capodimonte Salita Moiariello 16 NapoliI-80131 Italy Center for Cosmology and Particle Physics New York University Meyer Hall of Physics 4 Washington Place New YorkNY10003 United States Institut d’Astrophysique de Paris CNRS et Sorbonne Universités UPMC Paris 06 UMR 7095 98bis Bd Arago Paris75014 France Nicolaus Copernicus Astronomical Center Bartycka 18 Warsaw00-716 Poland Mullard Space Science Laboratory University College London Holmbury St. Mary Dorking SurreyRH5 6NT United Kingdom University of Turku Väisäläntie 20 Piikkiö21500 Finland Aalto University Metsähovi Radio Observatory PO Box 13000 AaltoFI-00076 Finland Department of Physics University of Alberta 4-181 CCIS EdmontonABT6G 2E1 Canada Faulkes Telescope Project School of Physics and Astronomy Cardiff University The Parade CardiffCF24 3AA United Kingdom Astrophysics Research Institute Liverpool John Moores University 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Space Sciences Laboratory University of California 7 Gauss Way BerkeleyCA94720-7450 United States International Centre for Radio Astronomy Research Curtin University GPO Box U1987 PerthWA6845 Australia Department of Physics and Astronomy Wheaton College NortonMA02766 United States Eureka Scientific Inc. 2452 Delmer Street OaklandCA94602 United States SRON Netherlands Institute for Space Research Sorbonnelaan 2 Utrecht3584 CA Netherlands Department of Physics & Astronomy University of Southampton SouthamptonSO17 1BJ United Kingdom Gymnase du Bugnon-Sévelin Avenue de Sévelin 44 Lausanne1004 Switzerland NUCLIO - N

We present optical, UV and X-ray monitoring of the short orbital period black hole X-ray binary candidate Swift J1753.5–0127, focusing on the final stages of its 12−year long outburst that started in 2005. From September 2016 onward, the source started to fade and within three months, the optical flux almost reached the quiescent level. Soon after that, using a new proposed rebrightening classification method we recorded a mini-outburst and a reflare in the optical light curves, peaking in February (V-17.0) and May (V-17.9) 2017, respectively. Remarkably, the mini-outburst has a peak flux consistent with the extrapolation of the slow decay before the fading phase preceding it. The following reflare was fainter and shorter. We found from optical colors that the temperature of the outer disk was - 11,000 K when the source started to fade rapidly. According to the disk instability model, this is close to the critical temperature when a cooling wave is expected to form in the disk, shutting down the outburst. The optical color could be a useful tool to predict decay rates in some X-ray transients. We notice that all X-ray binaries that show mini-outbursts following a main outburst are short orbital period systems ( Copyright © 2019, The Authors. All rights reserved.

关键词： Stars

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

学校读者我要写书评

暂无评论

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

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

学校读者我要写书评

暂无评论

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