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arXiv 1601.01692astro-ph.HEastro-ph.CO
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通过两个Macronova候选者的晚期射电观测检验磁星模型

Testing the Magnetar Model via Late Time Radio Observations of Two Macronova Candidates

Assaf Horesh, Kenta Hotokezaka, Tsvi Piran, Ehud Nakar, Paul Hancock

摘要:

紧凑的双星合并可能已经被观察到,因为它们是短伽马射线暴(sGRB)的主要模型。这些合并产生的喷射物中的放射性衰变预计会产生一个红外线耀斑,被称为macronova(或kilonova),时间尺度为一周。最近,在对sGRB的后续观察中发现了两个这样的macronova候选者,这加强了它们确实来自合并的可能性。由于与周围ISM的相互作用,同一喷出物也会产生长期(数月至数年)的无线电发射。为了寻找这种发射,我们用Jansky甚大阵列(VLA)和澳大利亚望远镜紧凑阵列(ATCA)观测了两个macronova候选者GRB 130603B和GRB 060614。我们的观测结果是零检测,对喷出物的动能和质量施加了很大的上限。合并的一个可能结果是一个高度磁化的中子星(磁星),它被认为是伽马射线暴的中心引擎。这样的磁星会将其能量的很大一部分沉积到喷出物中,导致更明亮的射电耀斑。因此,我们的结果排除了这两个事件中的磁星。

英文摘要:

Compact binary mergers may have already been observed as they are the leading model for short gamma-ray bursts (sGRBs). Radioactive decay within the ejecta from these mergers is expected to produce an infra-red flare, dubbed macronova (or kilonova), on a time scale of a week. Recently two such macronova candidates were identified in followup observations of sGRBs, strengthening the possibility that those indeed arise from mergers. The same ejecta will also produce a long term (months to years) radio emission due to its interaction with the surrounding ISM. In search for this emission, we observed the two macronova candidates, GRB 130603B and GRB 060614 with the Jansky very large array (VLA) and the Australia Telescope Compact Array (ATCA). Our observations resulted in null-detections, putting strong upper limits on the kinetic energy and mass of the ejecta. A possible outcome of a merger is a highly magnetized neutron star (a magnetar), which has been suggested as the central engine for GRBs. Such a magnetar will deposit a significant fraction of its energy into the ejecta leading to a brighter radio flare. Our results, therefore, rule out magnetars in these two events.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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