Multiwavelength observations of a TeV-Flare from W Comae
VERITAS collaboration, V. A. Acciari, E. Aliu, T. Aune, M. Beilicke, W. Benbow, M. Bottcher, D. Boltuch, J. H. Buckley, S. M. Bradbury, V. Bugaev, K. Byrum, A. … 展开作者
VERITAS collaboration, V. A. Acciari, E. Aliu, T. Aune, M. Beilicke, W. Benbow, M. Bottcher, D. Boltuch, J. H. Buckley, S. M. Bradbury, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, L. Ciupik, P. Cogan, W. Cui, R. Dickherber, C. Duke, A. Falcone, J. P. Finley, P. Fortin, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, G. H. Gillanders, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C. M. Hui, T. B. Humensky, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. LeBohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, J. Millis, P. Moriarty, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, A. Pichel, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, G. H. Sembroski, A. W. Smith, D. Steele, M. Theiling, S. Thibadeau, A. Varlotta, V. V. Vassiliev, S. Vincent, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, S. Wissel, M. Wood, The AGILE Team, :, E. Pian, S. Vercellone, I. Donnarumma, F. D'Ammando, A. Bulgarelli, A. W. Chen, A. Giuliani, F. Longo, L. Pacciani, G. Pucella, V. Vittorini, M. Tavani, A. Argan, G. Barbiellini, P. Caraveo, P. W. Cattaneo, V. Cocco, E. Costa, E. Del Monte, G. De Paris, G. Di Cocco, Y. Evangelista, M. Feroci, M. Fiorini, T. Froysland, M. Frutti, F. Fuschino, M. Galli, F. Gianotti, C. Labanti, I. Lapshov, F. Lazzarotto, P. Lipari, M. Marisaldi, M. Mastropietro, S. Mereghetti, E. Morelli, A. Morselli, A. Pellizzoni, F. Perotti, G. Piano, P. Picozza, M. Pilia, G. Porrovecchio, M. Prest, M. Rapisarda, A. Rappoldi, A. Rubini, S. Sabatini P. Soffitta, M. Trifoglio, A. Trois, E. Vallazza, A. Zambra, D. Zanello, C. Pittori, P. Santolamazza, F. Verrecchia, P. Giommi, S. Colafrancesco, L. Salotti, M. Villata, C. M. Raiteri, H. D. Aller, M. F. Aller, A. A. Arkharov, N. V. Efimova, V. M. Larionov, P. Leto, R. Ligustri, E. Lindfors, M. Pasanen, O. M. Kurtanidze, S. D. Tetradze, A. Lahteenmaki, M. Kotiranta, A. Cucchiara, P. Romano, R. Nesci, T. Pursimo, J. Heidt, E. Benitez, D. Hiriart, K. Nilsson, A. Berdyugin, R. Mujica, D. Dultzin, J. M. Lopez, M. Mommert, M. Sorcia, I. de la Calle Perez
We report results from an intensive multiwavelength campaign on the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy gamma-ray emission in June 2008. The very high energy gamma-ray signal was detected by VERITAS on 2008 June 7-8 with a flux F(>200 GeV) = (5.7+-0.6)x10^-11 cm-2s-1, about three times brighter than during the discovery of gamma-ray emission from W Com by VERITAS in 2008 March. The initial detection of this flare by VERITAS at energies above 200 GeV was followed by observations in high energy gamma-rays (AGILE, E>100 MeV), and X-rays (Swift and XMM-Newton), and at UV, and ground-based optical and radio monitoring through the GASP-WEBT consortium and other observatories. Here we describe the multiwavelength data and derive the spectral energy distribution (SED) of the source from contemporaneous data taken throughout the flare.
We report the discovery of a new low-mass X-ray binary near the center of the unassociated Fermi GeV gamma-ray source 4FGL J0540.0-7552. The source shows the persistent presence of an optical accretion disk and exhibits extreme X-ray and optical variability. It also has an X-ray spectrum well-fit by a hard power law with a Gamma = 1.8 and a high ratio of X-ray to gamma-ray flux. Together, these properties are consistent with the classification of the binary as a transitional millisecond pulsar (tMSP) in the sub-luminous disk state. Uniquely among the candidate tMSPs, 4FGL J0540.0-7552 shows co…
In the past years, evidence has started piling up that some high-energy cosmic neutrinos can be associated with blazars in flaring states. On February 26, 2022, a new blazar-neutrino coincidence has been reported: the track-like neutrino event IC220225A detected by IceCube is spatially coincident with the flat-spectrum radio quasar PKS 0215+015. Like previous associations, this source was found to be in a high optical and $γ$-ray state. Moreover, the source showed a bright radio outburst, which substantially increases the probability of a true physical association. We have performed six observ…
Particle acceleration signatures in the time-dependent one-zone synchrotron self-Compton model of blazar flares
LUX, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université(巴黎天文台,巴黎文理研究大学,法国国家科学研究中心,索邦大学);Centre for Space Research, North-West University(西北大学空间研究中心)
A Multiwavelength Study of a Long-Duration VHE Flare from BL Lacertae with VERITAS
CP3-Origins, University of Southern Denmark(南丹麦大学);DePauw University(迪堡大学);Temple University(天普大学);University of Utah(犹他大学);Washington University(华盛顿大学);University of California, Los Angeles(加州大学洛杉矶分校);California Polytechnic State University(加州州立理工大学);Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz(加州大学圣克鲁兹分校粒子物理研究所及物理系)
Predicting Multiwavelength Emission Associated with X-Ray Flares and Extended Emission of Gamma-Ray Bursts
Astronomical Institute, Graduate School of Science, Tohoku University(东北大学理学研究科天文学研究所);Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo(东京大学大学院综合文化研究科地球惑星科学专攻);Frontier Research Institute for Interdisciplinary Sciences, Tohoku University(东北大学跨学科前沿研究院);Department of Astronomy and Astrophysics, The Pennsylvania State University(宾夕法尼亚州立大学天文与天体物理系);Institute for Gravitation and the Cosmos, The Pennsylvania State University(宾夕法尼亚州立大学引力与宇宙学研究所);Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University(京都大学汤川理论物理研究所引力物理学与量子信息研究中心);Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences(中国科学院高能物理研究所粒子天体物理重点实验室及计算中心);TIANFU Cosmic Ray Research Center(天府宇宙线研究中心)
The exceptional 2017 gamma-ray flare of the radio galaxy NGC 1275: VERITAS and Multiwavelength Observations
CP3-Origins, University of Southern Denmark(南丹麦大学 CP3-起源中心);DePauw University(迪堡大学);Temple University(天普大学);University of Utah(犹他大学);University of California, Los Angeles(加州大学洛杉矶分校);California Polytechnic State University(加州州立理工大学);Washington University(华盛顿大学);Santa Cruz Institute for Particle Physics(圣克鲁斯粒子物理研究所);University of California, Santa Cruz(加州大学圣克鲁兹分校);Pennsylvania State University(宾夕法尼亚州立大学)
The flat-spectrum radio quasar 3C~454.3 throughout the years has presented very high activity phases (flares) in which the different wavebands increase their flux dramatically. In this work, we perform multiwavelength analysis from radio to gamma-rays and study the Mg~II~$λ2798$Å emission line and the UV~Fe~II band from 2008-2018. We found that an increase in the 43 GHz flux density of the quasi-stationary component C, coincides with the estimated time at which a superluminal blob ejected from the radio core (which caused the brightest flare of 2010) collides with the quasi-stationary componen…
Gamma-ray flare activity from PSR B1259-63 during 2014 periastron passage and comparison to its 2010 passage
PSR B1259-63/LS 2883是一个伽玛射线双星系统,其中包含一颗射电脉冲星,它围绕Be星运行在一个高椭圆轨道上,周期约3.4年。在其2010年的近星点通道中,观测到了从射电到TeV的多波长辐射,以及费米大面积望远镜(LAT)测量到的一个意想不到的GeV耀斑。在这里,我们报告了PSR B1259-63在其最近的2014年近星通过期间的LAT监测结果。我们比较了2010年和这次近星点的伽马射线行为,发现PSR B1259-63显示了一个周期性的GeV耀斑。这两个近星点通道的现象学的异同进行了讨论。
Active Galactic Nuclei in general, and the supermassive black hole in M87 in particular, show bright and rapid gamma-ray flares up to energies of 100 GeV and above. For M87, the flares show multiwavelength components, and the variability timescale is comparable to the dynamical time of the event horizon, suggesting that the emission may come from a compact region nearby the nucleus. However, the emission mechanism for these flares is not well understood. Recent high-resolution general-relativistic magnetohydrodynamic simulations show the occurrence of episodic magnetic reconnection events that…
Central Engine and Host Galaxy of RXJ 1301.9+2747: A Multiwavelength View of a Low-mass Black Hole Active Galactic Nuclei with Ultra-soft X-ray Emission
Reprocessed X-ray emission in Active Galactic Nuclei (AGN) can provide fundamental information about the circumnuclear environments of supermassive black holes. Recent mid-infrared studies have shown evidence of an extended dusty structure perpendicular to the torus plane. In this work, we build a self-consistent X-ray model for the Circinus Galaxy including the different physical components observed at different wavelengths and needed to reproduce both the morphological and spectral properties of this object in the mid-infrared. The model consists of four components: the accretion disk, the b…
Stellar sources of gamma rays are one of the front lines in modern astrophysics whose understanding can benefit from observational tools not originally designed for their study. We take advantage of the high precision photometric capabilities of present-day space facilities to obtain a new perspective on the optical behavior of the X-ray and gamma-ray binary LS I +61 303. Previously unknown phenomena whose effects manifest with amplitudes below 0.01 magnitude can now be clearly observed and studied. Our work is mainly based on the analysis of optical and gamma-ray archival data and uses the to…