并合驱动的长伽玛射线暴中心引擎的约束
Constraints on the central engine of merger-driven long gamma-ray bursts
浏览论文内容
中文总结 AI 辅助
通过射电观测和光变曲线建模，约束并合驱动长GRB的磁星中心引擎参数，发现射电未探测与低密度环境兼容，并限制其参数空间。
中文摘要 AI 辅助
最近的观测发现了一类新的长时标伽玛射线暴（GRB），它们很可能由致密双星并合产生。利用射电观测和光变曲线建模，我们研究了磁星残骸能否为这类并合驱动的GRB样本中观测到的长时标瞬时辐射提供能量。我们推导了对磁星转动能和磁场强度的约束，并评估了磁星中心引擎模型对观测事件是否可行。我们使用澳大利亚望远镜致密阵列（ATCA）对七个邻近的并合驱动GRB（$z<0.25$）进行了2.1 GHz射电观测，获得了爆发后520-6900天晚期射电辐射的灵敏上限。我们对磁星供能的抛射物与周介介质相互作用所产生的预期射电光变曲线进行了建模，并将其与我们的观测进行比较。我们另外使用回落吸积磁星模型，针对延展伽玛射线辐射单独检验了磁星假说。在所有观测的GRB中均未探测到射电对应体，2.1 GHz处的3$\sigma$流量密度上限为33-72 $\mu$Jy。对磁星供能的抛射物与周介介质相互作用所产生的预期同步辐射进行建模，我们发现射电未探测结果与低密度环境中的高能外流仍然兼容。对瞬时伽玛射线辐射的分析为磁星引擎的自转周期和磁场提供了补充约束。一旦考虑回落吸积和喷流重子负载，参数空间被严格限制。
英文摘要
Recent observations have identified a new class of long-duration gamma-ray bursts (GRBs) likely produced by compact binary mergers. Using radio observations and lightcurve modelling, we investigate whether a magnetar remnant can power the long-lasting prompt emission observed in this merger-driven GRB sample. We derive constraints on the magnetars' rotational energy and magnetic-field strength, and assess whether the magnetar central-engine model is viable for the observed events. We conducted 2.1 GHz radio observations of seven nearby merger-driven GRBs ($z<0.25$) using the Australia Telescope Compact Array (ATCA), obtaining sensitive upper limits on late-time radio emission 520-6900 days post-burst. We modelled the expected radio light curves from magnetar-energized ejecta interacting with the circumburst medium and compared them to our observations. We separately tested the magnetar hypothesis against the extended gamma-ray emission using a fallback-accreting magnetar model. No radio counterpart is detected in any of the observed GRBs, with 3$σ$ flux density upper limits of 33-72 $μ$Jy at 2.1 GHz. Modelling the expected synchrotron emission from magnetar-energized ejecta interacting with the circumburst medium, we find that the radio non-detections remain compatible with energetic outflows in low-density environments. The analysis of the prompt gamma-ray emission provides complementary constraints on the spin period and magnetic field of the magnetar engine. Once fallback accretion and jet baryon-loading are considered, the parameter space is narrowly confined.
发表机构
- Università di Tor Vergata（托尔维加塔大学）
- INAF–Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）
- The Open University of Israel（以色列开放大学）
- The University of Tokyo（东京大学）
- The Pennsylvania State University（宾夕法尼亚州立大学）
机构由 AI 辅助整理，请以论文原文为准。
