We present a simple analytic model for the structure of non-relativistic and relativistic radiation mediated shocks. At shock velocities β_s\equiv v_s/c\gtrsim 0.1, the shock transition region is far from thermal equilibrium, since the transition crossing time is too short for the production of a black-body photon density (by Bremsstrahlung emission). In this region, electrons and photons (and positrons) are in Compton (pair) equilibrium at temperatures T_s significantly exceeding the far downstream temperature, T_s\gg T_d\approx 2(\varepsilon n_u \hbar^3c^3)^{1/4}. T_s\gtrsim 10 keV is reached at shock velocities β_s\approx 0.2. At higher velocities, β_s\gtrsim0.6, the plasma is dominated in the transition region by e^\pm pairs and 60 keV\lesssim T_s \lesssim 200 keV. We argue that the spectrum emitted during the breaking out of supernova shocks from the stellar envelopes (or the surrounding winds) of Blue Super Giants and Wolf-Rayet stars, which reach β_s>0.1 for reasonable stellar parameters, may include a hard component with photon energies reaching tens or even hundreds of keV. This may account for the X-ray outburst associated with SN2008D, and possibly for other SN-associated outbursts with spectra not extending beyond few 100 keV (e.g. XRF060218/SN2006aj).
Shock breakout is the earliest, readily-observable emission from a core-collapse supernova explosion. Observing supernova shock breakout may yield information about the nature of the supernova shock prior to exiting the progenitor and, in turn, about the core-collapse supernova mechanism itself. X-ray Outburst 080109, later associated with SN 2008D, is a very well-observed example of shock breakout from a core-collapse supernova. Despite excellent observational coverage and detailed modeling, fundamental information about the shock breakout, such as the radius of breakout and driver of the lig…
Observable Signatures of Supernova Shock Breakout in Confined Circumstellar Medium
National Taiwan University(台湾大学);Academia Sinica, Institute of Astronomy and Astrophysics(中央研究院天文及天文物理研究所);Heidelberger Institut für Theoretische Studien(海德堡理论研究所);Kyoto University(京都大学);Zentrum für Astronomie der Universität Heidelberg(海德堡大学天文学计算中心)
We present three-dimensional simulations of core-collapse supernovae using the FLASH code that follow the progression of the explosion to the stellar surface, starting from neutrino-radiation hydrodynamic simulations of the neutrino-driven phase performed with the CHIMERA code. We consider a 9.6-$M_{\odot}$ zero-metallicity progenitor starting from both 2D and 3D CHIMERA models, and a 10-$M_{\odot}$ solar-metallicity progenitor starting from a 2D CHIMERA model, all simulated until shock breakout in 3D while tracking 160 nuclear species. The relative velocity difference between the supernova sh…
The discovery of early bumps in some type-I superluminous supernovae (SLSNe-I) before the main peaks offers an important clue to their energy source mechanisms. In this paper, we updated an analytic magnetar-powered model for fitting the multi-band light curves of double-peaked SLSNe-I: the early bump is powered by magnetar-driven shock breakout thermal emission, and the main peak is powered by a radiative diffusion through the SN ejecta as in the standard magnetar-powered model. Generally, the diffusive luminosity is greater than the shock breakout luminosity at the early time, which makes th…
High-Energy Neutrinos from Supernova Shock Breakouts in Circumstellar Media: Light Curves, Spectra, and Contribution to the Extragalactic Neutrino Background
Weizmann Institute of Science(魏茨曼科学研究所);The Pennsylvania State University(宾夕法尼亚州立大学);Kyoto University(京都大学)
A dozen X-ray supernova shock breakout (SN SBO) candidates were reported recently based on XMM-Newton archival data, which increased the X-ray selected SN SBO sample by an order of magnitude. Assuming they are genuine SN SBOs, we study the luminosity function (LF) by improving upon the method used in our previous work. The light curves and the spectra of the candidates were used to derive the maximum volume within which these objects could be detected with XMM-Newton by simulation. The results show that the SN SBO LF can be described by either a broken power law (BPL) with indices (at the 68$\…
High-Energy Shock Breakout from Supernovae and Gamma-ray Bursts
Center for Nonlinear Studies, Los Alamos National Laboratory(洛斯阿拉莫斯国家实验室非线性研究中心);Department of Physics & Astronomy, Louisiana State University(路易斯安那州立大学物理与天文学系);X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center(NASA戈达德太空飞行中心X射线天体物理学实验室);McWilliams Center for Cosmology and Astrophysics, Department of Physics, Carnegie Mellon University(卡内基梅隆大学物理学院麦克威廉斯宇宙学与天体物理学中心)
There are currently many large-field surveys operational and planned including the powerful Vera C. Rubin Observatory Legacy Survey of Space and Time. These surveys will increase the number and diversity of transients dramatically. However, for some transients, like supernovae (SNe), we can gain more understanding by directed observations (e.g. shock breakout, $γ$-ray detections) than by simply increasing the sample size. For example, the initial emission from these transients can be a powerful probe of these explosions. Upcoming ground-based detectors are not ideally suited to observe the ini…
Multi-wavelength Signatures of Supernova Shock Breakout from Red Supergiants in Two Dimensions
National Taiwan University(台湾大学);Academia Sinica, Institute of Astronomy and Astrophysics(中央研究院天文及天文物理研究所);Heidelberger Institut für Theoretische Studien(海德堡理论研究所);RIKEN Pioneering Research Institute (PRI)(理化学研究所前沿研究 institutes);Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechenzentrum(海德堡大学天文学中心天文计算中心)
Multicolor light curves simulations of Population III core-collapse supernovae: from shock breakout to $^{56}$Co decay
由于缺乏实际观测,第一代恒星及其超新星(SN)爆炸的性质仍然未知。最近进行了许多瞬态调查和探测超新星(SNe)的Pop III星的可行性正在增长。本文研究了一些无金属核坍缩超新星模型(25-100 M $_{\odot}$)的光变曲线,为寻找和鉴别第一代超新星提供了指示。我们使用混合回落超新星爆炸模型,解释所观察到的丰富的贫金属恒星的模式。用多群辐射流体动力学程序STELLA对双光子光变曲线进行了数值计算。计算的光变曲线的非零金属丰度模型和几个观察到的SNe进行了比较。我们发现,冲击波爆发特征、光球速度演化、亮度、坪期和坪色演化等SN相都有助于估算SN祖星的质量、半径、爆炸能量和金属丰度等参数。我们的结论是,在当前(斯巴鲁/HSC)和未来的瞬态调查(LSST,JWST)的第一代SNe的潜在的光曲线可以被用来识别。它们也适用于识别附近宇宙中的低金属丰度SNe(PTF,Pan-STARRS,Gaia)。
The shock breakout emission is the first light that emerges from a supernova. In the spherical case it is characterized by a brief UV flash. In an axisymmetric, non-spherical prolate explosion, the shock first breaches the surface along the symmetry axis, then peels around to larger angles, producing a breakout light curve which may differ substantially from the spherically symmetric case. We study the emergence of a non-relativistic, bipolar shock from a spherical star, and estimate the basic properties of the associated bolometric shock breakout signal. We identify four possible classes of b…