Type-I X-ray bursts are recurring thermonuclear explosions on the surface of accreting neutron stars. Matching observed bursts to computational models can help to constrain system properties, such as the neutron star mass and radius, crustal heating rates, and the accreted fuel composition, but systematic parameter studies to date have been limited. We apply Markov chain Monte Carlo methods to 1D burst models for the first time, and obtain system parameter estimations for the `Clocked Burster', GS 1826$-$238, by fitting multiple observed epochs simultaneously. We explore multiple parameters which are often held constant, including the neutron star mass, crustal heating rate, and hydrogen composition. To improve the computational efficiency, we precompute a grid of 3840 KEPLER models - the largest set of 1D burst simulations to date - and by interpolating over the model grid, we can rapidly sample burst predictions. We obtain estimates for a CNO metallicity of $Z_\mathrm{CNO} = 0.010^{+0.005}_{-0.004}$, a hydrogen fraction of $X_0 = 0.74^{+0.02}_{-0.03}$, a distance of $d \sqrt{ξ_\mathrm{b}} = 6.5^{+0.4}_{-0.6}\, \mathrm{kpc}$, and a system inclination of $i = {69^{+2}_{-3}}^{\circ}$.
Diverse Properties of Interstellar Medium Embedding Gamma-Ray Bursts at the Epoch of Reionization
分析超高分辨率大尺度宇宙辐射流体动力学模拟,首次量化的物理环境的长持续时间伽马射线暴(GRB)在再电离的时代。我们发现,在秒差距尺度上,13%的伽玛暴保持在高密度($\ge 10^4$ cm $^{-3}$)的低温恒星形成区域,而87%的伽玛暴发生在低密度($\sim 10^{-2.5}$ cm $^{-3}$)的高温区域超新星加热。更重要的是,伽玛射线暴余辉的光谱特性,如中性氢柱密度,总氢柱密度,尘埃柱密度,气体温度和金属含量的干预吸收剂,从视线到视线变化很大。虽然我们的模型解释了现存的有限的观测推断值环暴密度,金属丰度,柱密度和灰尘的属性,一个大得多的样本高Z伽玛暴余辉将需要促进模型的统计坚实的测试。我们的研究结果表明,任何试图推断的物理性质(如金属丰度)的星际介质的主机星系的基础上非常少量的(通常是一个)视线将是不稳定的。利用高Z伽玛暴探测星际介质和星系际介质时,应考虑到星际介质的物理性质。
A Search for Rotation Measure Flare Candidates in Repeating Fast Radio Bursts
Purple Mountain Observatory, Chinese Academy of Sciences(中国科学院紫金山天文台);State Key Laboratory of Radio Astronomy and Technology, Purple Mountain Observatory, Chinese Academy of Sciences(中国科学院紫金山天文台射电天文与技术重点实验室)
Second-scale periodicity in FRB 20201124A: coincident with critical RM evolution epochs and its possible implications
Qufu Normal University(曲阜师范大学);Institute of High Energy Physics, Chinese Academy of Sciences(中国科学院高能物理研究所);Purple Mountain Observatory, Chinese Academy of Sciences(中国科学院紫金山天文台);University of Science and Technology of China(中国科学技术大学);Nanjing University(南京大学);University of Chinese Academy of Sciences(中国科学院大学);Central China Normal University(华中师范大学)
A MeerKAT search for persistent radio sources towards twenty-five localised Fast Radio Bursts
North-West University(西北大学);University of South Africa(南非大学);University of Nigeria(尼日利亚大学);National Institute for Theoretical and Computational Sciences (NITheCS)(国家理论与计算科学研究所);South African Radio Astronomy Observatory(南非射电天文台);Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester(曼彻斯特大学物理与天文学系乔德雷克天体物理学中心)
Synchrotron Self-Compton Model of TeV Afterglows in Gamma-Ray Bursts
Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México(墨西哥国立自治大学射电天文学与天体物理研究所);Department of Natural Sciences, The Open University of Israel(以色列开放大学自然科学系);Astrophysics Research Center of the Open university (ARCO), The Open University of Israel(以色列开放大学天体物理学研究中心);Department of Physics, The George Washington University(乔治华盛顿大学物理系)
Constraining neutron-star properties with ensembles of thermonuclear bursts: application to SRGA J144459.2-604207
Monash University(莫纳什大学);Institute for Globally-Distributed Research and Education (IGDORE)(全球分布式研究与教育学院);International Centre for Radio Astronomy Research, Curtin University(科廷大学国际射电天文研究中心);Xiangtan University(湘潭大学);Qingdao University of Technology(青岛理工大学)
Gamma ray bursts may be blueshifted bundles of the relic radiation
提出了一个假说,即伽马射线暴(GRB)可能是由最后一个散射时期产生的氢和氦的发射辐射发生蓝移而产生的。蓝移机制由这样的Lemaittre-Tolman(L-T)模型提供,其中爆炸时间函数$t_B(r)$不是处处恒定。蓝移发生在\textit{radial}射线上,该射线在$\dril{t_B} r \neq 0$的区域上发射。本文提出了一个适用于此目的的L-T模型,并说明了它是如何解释伽玛暴的观测性质的,有些性质只是定性地解释。
Variation of Microphysical Parameters in Reverse-shock Scenario
Instituto de Astronomía, Universidad Nacional Autónoma de México(墨西哥国立自治大学天文学研究所);Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS)(基础科学研究院宇宙理论物理中心);Instituto de Física, Universidad Nacional Autónoma de México(墨西哥国立自治大学物理研究所);Division of Science, National Astronomical Observatory of Japan(日本国立天文台科学部);The Graduate University for Advanced Studies (SOKENDAI)(综合研究大学院大学)
Hierarchical Bayesian Inference on the intrinsic event rate of Type I gamma-ray bursts from the {\it Fermi}/GBM catalogue
Institute of High Energy Physics, Chinese Academy of Sciences(中国科学院高能物理研究所);University of Chinese Academy of Sciences(中国科学院大学);Beijing Academy Science and Technology Branch(北京科学院技术分院)
The Origin of Cross-Energy-Similar FRED Profiles in Gamma-Ray Bursts Pulses
State Key Laboratory of Particle Astrophysics, 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国家重点实验室);University of Chinese Academy of Sciences(中国科学院大学);Department of Physics and Earth Sciences, University of Ferrara(费拉拉大学地球科学系);INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna(意大利国家天体物理研究所博洛尼亚天文与空间科学观测站);School of Physics and Electronic Science, Guizhou Normal University(贵州师范大学物理与电子科学学院)
Descalarization bursts from Galactic supramassive neutron stars: a kHz continuous-wave target
Eberhard Karls University of Tübingen(蒂宾根大学);Universitat de València(瓦伦西亚大学);Observatorio Astronómico, Universitat de València(瓦伦西亚大学天文台);Sofia University(索非亚大学);Institute of Mathematics and Informatics, Bulgarian Academy of Sciences(保加利亚科学院数学与计算机科学研究所)
GRB 080913的光谱红移为z=6.7,是最近发现的伽马射线暴GRB 090423(红移约为8.2)之前最遥远恒星天体的记录保持者。逐渐积累的高红移伽玛暴样品为宇宙再电离期伽玛暴的起源和物理提供了新的线索。本文对GRB 080913光学余辉的多波长数据进行了详细的数值拟合,并对它的环爆环境和其他模型参数进行了约束。我们的结论是,晚光学/X射线平台约一天,因为爆发是由于坡印廷通量占主导地位的注入从中央引擎,这很可能是一个巨大的旋转黑洞与超强磁场。