We present archival radio observations of SN1996cr from ATCA and MOST, and model its radio lightcurves using X-ray constrained hydrodynamical simulations of the interaction between the SN ejecta and the CSM. The early radio data show signs of free-free absorption (FFA), which decreases gradually and is minimal above 1.4 GHz after day ~3000. FFA optical depth constraints provide estimates of the CSM free electron density, which allows insight into the ionisation of SN1996cr's CSM and offers a test on the density distribution adopted by the hydrodynamical simulation. The intrinsic spectral index of the radiation shows evidence for spectral flattening, which is characterised by alpha = 0.852 +/- 0.002 at day 3000 and a decay rate of d_alpha = -0.014 +/- 0.001 yr^-1. The similarity in the spectral flattening of SN1987A, SN1993J, and SN1996cr suggests this may be a relatively common feature of SNe/CSM shocks. We adopt this spectral index variation to model the synchrotron radio emission of the shock, and consider several scalings that relate the parameters of the hydrodynamical simulation to the magnetic field and electron distribution. The simulated light curves match the large-scale features of the observed light curves, but fail to match certain tightly constraining sections. This suggests that simple energy density scalings may not be able to account for the complexities of the true physical processes at work, or alternatively, that the parameters of the simulation require modification in order to accurately represent SN1996cr's CSM.
The structure of TeV-bright shell-type supernova remnants
目标。二维MHD模拟用于模拟TeV亮壳型超新星遗迹(SNRs)的发射特性,并探索其性质。方法.在TeV辐射的轻子假设中,$γ$射线辐射是由SNR冲击加速的高能电子通过背景软光子的逆康普顿散射产生的。TeV辐射率与磁场能量密度成正比,MHD模拟可直接模拟此类残留物的TeV结构。二维MHD模拟信噪比进行的假设下,周围的星际介质是湍流的磁场和密度波动遵循Kolmogorov类幂律谱。结果(1)正如预期的那样,这些模拟证实了这些源的早期一维和二维模型,即冲击波的流体动力学演化和瑞利-泰勒对流和在湍流介质中传播的冲击对磁场的放大;(2)我们再现了$γ$射线的相当复杂的形态结构,表明源形态的内在变化与祖细胞和环境的结构无关;(3)在$0.1-1$ cm $^{-3}$的环境介质密度下,观测到的几个残留物的径向剖面得到了很好的再现。甚至更低的环境密度导致TeV亮度随半径的急剧下降,而不是在这些残余物的外缘附近观察到的。结论.在湍流背景介质中,我们可以重现几个壳型TeV SNR的合理的参数,除了一个更高的环境密度比从X射线观测推断的观察到的特性。
Constraints on magnetic field strength in the remnant SN1006 from its nonthermal images
SN 1006的图像具有许多重要特性。例如,明亮的边缘在空间上在不同的波段重合,它们有不同的亮度,亮度的对比度从无线电到伽马射线都不同。讨论了产生这种特性的原因和磁场强度的作用。简单的,几乎模型无关的方法和解析近似推导出的磁场的强度从比较无线电,X射线和TeV图像的SNR。这些方法要求TeV图像具有良好的分辨率和准确性,至少达到射电和X射线图的水平,以便对磁场施加合理的约束。如果我们将其应用于目前的HESS数据,他们将SN 1006四肢的磁场强度限制在低于几百微高斯的值。如果应用到费米-LAT波段,该模型预测相同的位置和相同的比例的表面亮度为GeV的光子为无线电波段。我们的结论是,TeV和GeV的未来高分辨率数据可能是非常翔实的MF的SN 1006。
Radio Continuum Study of One of the Brightest Large Magellanic Cloud Supernova Remnants N 132D
Western Sydney University(西悉尼大学);Gifu University(岐阜大学);Dominion Radio Astrophysical Observatory, Herzberg Astronomy & Astrophysics, National Research Council Canada(加拿大国家研究委员会赫茨伯格天文学与天体物理学部 Dominion 射电天文台);Center for Space Research and Utilization Promotion (c-SRUP), Gifu University(岐阜大学空间研究与利用促进中心(c-SRUP));Department of Astronomy and Space, College of Science, University of Baghdad(巴格达大学理学院天文学与空间系);Department of Astronomy, Faculty of Mathematics, University of Belgrade(贝尔格莱德大学数学学院天文学系);Isaac Newton Institute of Chile, Yugoslavia Branch(智利艾萨克·牛顿研究所南斯拉夫分部);Australia Telescope National Facility, CSIRO, Space and Astronomy(CSIRO太空与天文澳大利亚望远镜国家设施);Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia(塞尔维亚贝尔格莱德Volgina路7号天文台)
Observations of ionized carbon towards the $γ$-ray-bright supernova remnant RX J1713.7-3946
Adelaide University(阿德莱德大学);University of Cologne(科隆大学);Armagh Observatory and Planetarium(阿尔马天文台和天文馆);University of New South Wales(新南威尔士大学);Nagoya University(名古屋大学);Gifu University(岐阜大学);Western Sydney University(西悉尼大学)
CosmoDRAGoN III: Shaping the Afterlife -- How Progenitors and Environments Sculpt Radio Galaxy Remnants
University of Tasmania(塔斯马尼亚大学);ASTRON, the Netherlands Institute for Radio Astronomy(荷兰射电天文研究所);University of Hertfordshire(赫特福德大学);CSIRO Space and Astronomy(澳大利亚联邦科学与工业研究组织空间与天文部门);International Centre for Radio Astronomy Research, University of Western Australia(西澳大利亚大学国际射电天文研究中心)