A Decade of SN1993J: Discovery of Wavelength Effects in the Expansion Rate
J. M. Marcaide, I. Marti-Vidal, A. Alberdi, M. A. Perez-Torres, E. Ros, P. J. Diamond, J. C. Guirado, L. Lara, I. I. Shapiro, C. J. Stockdale, K. W. Weiler, F. … 展开作者
J. M. Marcaide, I. Marti-Vidal, A. Alberdi, M. A. Perez-Torres, E. Ros, P. J. Diamond, J. C. Guirado, L. Lara, I. I. Shapiro, C. J. Stockdale, K. W. Weiler, F. Mantovani, R. A. Preston, R. T. Schilizzi, R. A. Sramek, C. Trigilio, S. D. Van Dyk, A. R. Whitney
We have studied the growth of the shell-like radio structure of supernova SN1993J in M81 from September 1993 through October 2003 with very-long-baseline interferometry (VLBI) observations at the wavelengths of 3.6, 6, and 18cm. For this purpose, we have developed a method to accurately determine the outer radius (R) of any circularly symmetric compact radio structure like SN1993J.
The source structure of SN1993J remains circularly symmetric (with deviations from circularity under 2%) over almost 4000 days. We characterize the decelerated expansion of SN 1993J through approximately day 1500 after explosion with an expansion parameter $m= 0.845\pm0.005$ ($R \propto t^{m}$). However, from that day onwards the expansion is different when observed at 6 and 18cm. Indeed, at 18cm, the expansion can be well characterized by the same $m$ as before day 1500, while at 6cm the expansion appears more decelerated, and is characterized by another expansion parameter, $m_{6}= 0.788\pm0.015$. Therefore, since about day 1500 on, the radio source size has been progressively smaller at 6cm than at 18cm. These findings are in stark contrast to previous reports by other authors on the details of the expansion. In our interpretation the supernova expands with a single expansion parameter, $m= 0.845\pm0.005$, and the 6cm results beyond day 1500 are due to physical effects, perhaps also coupled to instrumental limitations. Two physical effects may be involved: (a) a changing opacity of the ejecta to the 6cm radiation, and (b) a radial decrease of the magnetic field in the emitting region.
(Long abstract cut. Please, read full abstract in manuscript).
A decade of multi-wavelength observations of the TeV blazar 1ES 1215+303: Extreme shift of the synchrotron peak frequency and long-term optical-gamma-ray flux increase
耀变体以其在所有波长的宽时间尺度上的可变性而闻名。大多数TeV伽玛射线耀变体的研究集中在短时间尺度上，特别是在耀斑期间。利用Fermi-LAT和VERITAS的十年观测，我们对blazar 1 ES 1215+303（z=0.130）的长期多波长射电到伽马射线通量密度变化进行了广泛的研究，并增加了几个短期射电结构和光学偏振观测，重点关注其伽马射线发射从100 MeV到30 TeV。在十年期间观测到多个强GeV伽马射线耀斑，伽马射线和光通量基线的长期增加以及这两个波段之间的线性相关。在源的射电形态和宽带频谱中识别出典型的HBL行为。VLBA在43.1，22.2和15.3 GHz的最里面的射流解决了三个固定的功能。我们采用了两个组件的同步自康普顿模型来描述不同的通量状态的源，包括在此期间，观察到的能量的同步峰值频率从红外到软X射线的极端移位的时代。
SVOM discovery of a strong X-ray outburst of the blazar 1ES~1959+650 and multi-wavelength follow-up with the Neil Gehrels Swift observatory
Université Paris Cité, CNRS, Astroparticule et Cosmologie（巴黎西岱大学）；Max-Planck-Institut für Radiostronomie（马克斯·普朗克射电天文研究所）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Northern Kentucky University（北肯塔基大学）；Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS（斯特拉斯堡天文台，斯特拉斯堡大学）；University of Science and Technology of China（中国科学技术大学）
New galaxy cluster in the Zone of Avoidance SRGe CL0512.7+3712. Discovery and multi-wavelength characterization
Max Planck Institute for Astrophysics（马克斯·普朗克天体物理研究所）；Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford（牛津大学理论物理学鲁道夫·皮尔斯中心）；Space Research Institute (IKI)（空间科学研究院）；Kazan Federal University（喀山联邦大学）；Tatarstan Academy of Sciences（鞑靼斯坦科学院）；Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森尼天体物理中心）
VLASS Discovery of a Luminous Galactic Radio Transient Evolving on Decade Timescales
California Institute of Technology（加州理工学院）；National Radio Astronomy Observatory（美国国家射电天文台）；Center for Astrophysics – Harvard & Smithsonian（哈佛-史密森尼天体物理中心）；University of California, Berkeley（加州大学伯克利分校）；University of California Santa Cruz（加州大学圣克鲁兹分校）；University of Toronto（多伦多大学）
Discovery of minute-scale polarization angle rotation in a supermassive black hole jet
University of Crete（克里特大学）；Foundation for Research and Technology-Hellas（希腊研究与技术基金会）；The Pennsylvania State University（宾夕法尼亚州立大学）；Institute of Astrobiology, University of Crete（克里特大学天体生物学研究所）；Chalmers University of Technology（查尔姆斯理工大学）；Friedrich-Alexander Universität Erlangen-Nürnberg（埃尔朗根-纽伦堡弗里德里希·亚历山大大学）
