GRB 131014 A：伽马射线暴热辐射和非热辐射研究实验室及新的L-PDMATHAAB-E $_\mathrm{peak,i}^\mathrm{nTh,rest}$关系
GRB 131014A: a Laboratory to Study the Thermal-Like and Non-Thermal Emissions in Gamma-Ray Bursts, and the new L$_\mathrm{i}^\mathrm{nTh}$-E$_\mathrm{peak,i}^\mathrm{nTh,rest}$ relation
S. Guiriec, R. Mochkovitch, T. Piran, F. Daigne, C. Kouveliotou, J. Racusin, N. Gehrels, J. McEnery
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13 pages of article including 9 figures + 13 pages of Appendix (1 figure and 1 table), Submitted to ApJ (Received July 23, 2015)
Evidence has been accumulated on the existence of a thermal-like component during the prompt phase of GRBs. This component, often associated with the GRB jet's photosphere, is usually subdominant compared to a much stronger non-thermal one. The prompt emission of Fermi GRB 131014A provides a unique opportunity to study this thermal-like component. Indeed, the thermal emission in GRB 131014A is much more intense than in other GRBs and a pure thermal episode is observed during the initial 0.16 s. The thermal-like component cools monotonically during the first second while the non-thermal emission kicks off. The intensity of the non-thermal component progressively increases until being energetically dominant at late time. This is a perfect scenario to disentangle the thermal component from the non-thermal one. A low-energy spectral index of +0.6 better fit the thermal component than the typical index value +1 corresponding to a pure Planck function. The non-thermal component is adequately fitted with a Band function whose low and high energy power law indices are ~-0.7 and <~-3, respectively; this is also statistically equivalent to a cutoff power law with a ~-0.7 index. This is in agreement with our previous results. Finally, a strong correlation is observed between the time-resolved luminosity of the non-thermal component, L$_i^{nTh}$, and its corresponding rest frame spectral peak energy, E$_{peak,i}^{rest,nTh}$, with a slope similar to the one reported in our previous articles. Assuming this relation to be universal for all GRBs we estimate a redshift of ~1.55 for GRB 131014A that is a typical value for long GRBs. These observational results are consistent with the models in which the non-thermal emission is produced well above the GRB jet photosphere but they may also be compatible with other scenarios (e.g., dissipative photosphere) that are not discussed in this article.
Maximum Energy of Particles Accelerated in Gamma-Ray Burst Afterglow Shocks
Purdue University（普渡大学）；Universidad Nacional de Colombia（哥伦比亚国立大学）；The Open University of Israel（以色列开放大学）；Astrophysics Research Center of the Open University (ARCO), The Open University of Israel（以色列开放大学天体物理研究中心）；The George Washington University（乔治华盛顿大学）；KU Leuven（荷语鲁汶大学）；Columbia University（哥伦比亚大学）；Center for Computational Astrophysics, Flatiron Institute（纽约联邦研究院计算天体物理学中心）
Search for Gamma Ray Bursts with the ARGO-YBJ Detector in Shower Mode
ARGO-YBJ探测器位于羊八井宇宙线实验室（4300 m a. S. L.，中国西藏）是一个全覆盖的空气簇射阵列，专门用于伽马射线天文学和宇宙射线研究。宽视场（~ 2 sr）和高占空比（> 86%）使ARGO-YBJ适合于搜索短暂和意外的伽马射线发射，如伽马射线暴（GRB）。在2007年11月6日至2013年2月7日期间，ARGO-YBJ的视野内发生了156个卫星触发的伽玛暴（其中24个具有已知的红移）。在10-100 GeV和10-1000 GeV两个能量范围内对这些伽玛暴可能的辐射进行了研究。在与卫星探测的时间重合方面，也没有在爆发后一小时的时间窗内发现明显的过量。考虑到EBL吸收，在99%的置信水平的能量注量的上限进行了评估，从~ 10-5 erg cm-2到~10-1 erg cm-2的值。
