Fast Blue Optical Transients (FBOTs) are luminous transients with fast evolving (typically $t_{\rm rise}<12\ \rm days$) light curve and blue color (usually $\rm {-0.2\ >\ g-r\ >\ -0.3}$) that cannot be explained by a supernova-like explosion. We propose a radiative diffusion in a time-dependent outflow model to interpret such special transients. In this model, we assume a central engine ejects continuous outflow during a few days. We consider the ejection of the outflow to be time-dependent. The outflow is optically thick initially and photons are frozen in it. As the outflow expands over time, photons gradually escape, and our work is to model such an evolution. Numerical and analytical calculations are considered separately, and the results are consistent. We apply the model to three typical FBOTs: PS1-10bjp, ZTF18abukavn, and ATLAS19dqr. The modeling finds the total mass of the outflow ($\sim 1-5 {M_{\odot}}$), and the total time of the ejection ($\sim$ a few days) for them, leading us to speculate that they may be the result of the collapse of massive stars.
Outflow from unmagnetized shocked radiative transonic accretion disk around a black hole
Indian Institute of Science Education and Research Kolkata(印度科学教育研究所加尔各答分校);Center of Excellence in Space Sciences India, Indian Institute of Science Education and Research Kolkata(印度太空科学卓越中心,印度科学教育研究所加尔各答分校)
Outflowing photoionized plasma in Circinus X-1 using the high-resolution X-ray spectrometer Resolve onboard XRISM and the radiative transfer code cloudy
The spectra of a radiative reprocessing outflow model for fast blue optical transients
School of Physics and Astronomy, Sun Yat-sen University(中山大学物理学院);CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area, Sun Yat-sen University(中山大学粤港澳大湾区子午线科学中心)
AGN radiative feedback as the main regulator of [O III] outflow activity and obscuration in X-ray AGN
Max-Planck-Institut für Extraterrestrische Physik(马克斯·普朗克地外物理研究所);Excellence Cluster ORIGINS(ORIGINS卓越集群);School of Physics and Astronomy, Tel Aviv University(特拉维夫大学物理与天文学学院);INAF-Osservatorio Astronomico di Capodimonte(意大利国家天体物理研究所卡波迪蒙特天文台);Centre for Extragalactic Astronomy, Department of Physics, Durham University(达勒姆大学物理系河外天文中心)
SIROCCO: A Publicly Available Monte Carlo Ionization and Radiative Transfer Code for Astrophysical Outflows
外流是许多天体物理系统的重要组成部分,包括吸积致密双星和活动星系核(AGN)。这些外流可以显著影响系统的演化,并通过对中央引擎产生的辐射进行再处理来改变其观测外观。Sirocco(Simulating Ionization and Radiation in Outflows Created by Compact Objects -或“以前称为Python的代码”)是一个基于Sobolev的蒙特卡罗电离和辐射转移代码。它的目的是模拟任何系统产生的光谱与方位角对称流出,从球形恒星风旋转,双锥吸积盘风。风模型可以参数化或导入,例如从流体动力学模拟。辐射源包括光学厚吸积盘和各种具有灵活光谱和几何形状的中心源。该代码跟踪在任何给定模拟中由源产生的“光子包”,因为它们穿过风并与风相互作用。该代码假设辐射接近平衡,所以热和电离状态可以从这些相互作用迭代确定。一旦风中的物理特性收敛,Sirocco可以用于在一系列观察者视线处生成合成光谱。在这里,我们描述的物理假设,操作,性能和代码的限制。我们验证它对tardis,cmfgen和多云,找到良好的协议,并提出说明性的合成光谱盘风在灾难性的变量,潮汐破坏事件,活动星系核和X射线双星。Sirocco可在GitHub上公开获取,其相关数据,文档和样本输入文件涵盖了广泛的天体物理应用。
Resolving the soft X-ray ultra fast outflow in PDS 456
过去对附近发光类星体PDS 456(在$z=0.184$)的X射线观测揭示了广角吸积盘风(Nardini et al. 2015),流出速度为$\sim-0.25c$,通过观测其蓝移的铁K壳层吸收线轮廓观察到。在这里,我们提出了PDS 456的三个新的XMM-牛顿观测;一个在2018年9月,类星体明亮且无特征,两个在2019年9月,相隔22天,发生在类星体昏暗五倍的时候,并且存在强烈的风蓝移线。在2019年9月的第二次观测中,在高分辨率RGS光谱中分辨出了三条宽吸收线($σ=3000$ km s $^{-1}$),它们被确定为蓝移的OVIII Ly $α$,NeIX He $α$和NeX Ly $α$。发现这种软X射线吸收体的流出速度为$v/c=-0.258\pm0.003$,与具有$v/c=-0.261\pm0.007$的铁K吸收体完全一致。与铁K处的高电离风($\logξ=5$、$N_{\rm H}=7\times10^{23}$ cm $^{-2}$)相比,软X射线成分($\logξ=3.4$、$N_{\rm H}=2\times10^{21}$ cm $^{-2}$)流出的电离参数和柱密度低约两个数量级。在2019年的观察结果之间,在软X射线吸收体中观察到了显著的变化,在20天内从$N_{\rm H}=10^{23}$ cm $^{-2}$下降到$N_{\rm H}=10^…