伽马射线暴多波段余辉中能量注入平台期的统计关系
A statistical relation of energy injection plateaus in multi-band afterglows of gamma-ray bursts
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中文总结 AI 辅助
本研究通过47个双波段平台期伽马射线暴样本，证实其平台期X射线与光学光度呈中等正相关、正常衰减期斜率相近，支持能量注入模型，为检验该模型提供了有效诊断方法。
中文摘要 AI 辅助
伽马射线暴（GRB）余辉中平台期的起源仍存在争议，能量注入模型是最具竞争力的解释之一。若平台期确实由能量注入驱动，那么平台期的平均X射线光度$L_{\rm X, plat, ave}$和光学光度$L_{\rm opt, plat, ave}$应存在关联；此外，由于平台期和正常衰减期的光度均源于外激波的同步辐射，二者的标度关系应一致，因此多波段同时观测对验证该机制至关重要。本研究选取了47个具备双波段平台期的GRB样本，计算了它们平台期及后续正常衰减期的时间平均各向同性光度，发现平台期存在中等强度的正相关关系$\boldsymbol{\rm log} L_{\rm X, plat, ave}=m\boldsymbol{\rm log} L_{\rm opt, plat, ave}+c$，其斜率$m=0.86\boldsymbol{\rm ±}0.11$，该相关性支持能量注入起源，并提供了检验该模型的有效诊断方法；此外，正常衰减期的斜率$m=1.05\boldsymbol{\rm ±}0.05$与平台期相近，进一步证实两个阶段具有相同的物理起源。值得注意的是，平台期后的光度存在系统性下移，这可能预示中心引擎的停止。
英文摘要
The origin of the plateau phase in gamma-ray burst (GRB) afterglows remains under debate, with the energy injection model being one of the most competitive explanations. If the plateau is truly driven by energy injection, the average X-ray and optical luminosities during the plateau phase, $L_{\rm X, plat, ave}$ and $L_{\rm opt, plat, ave}$, should naturally be correlated. Moreover, under this scenario, the scaling relations between the luminosities during the plateau and the normal decay phase are expected to be consistent since they share the same origin, i.e., synchrotron radiation from the external forward shock. Therefore, simultaneous multi-band observations are essential to verify this mechanism. In this work, we select a sample of 47 GRBs with simultaneous plateaus in both bands. We calculate their time-averaged isotropic luminosities for the plateau and the subsequent normal decay phases. We find a moderate positive correlation $\log L_{\rm X, plat, ave}=m\log L_{\rm opt, plat, ave}+c$ with a slope $m = 0.86 \pm 0.11$ for the plateau phase. This correlation supports the energy injection origin and offers a promising diagnostic approach to test the model. Furthermore, we obtain a similar slope $m = 1.05 \pm 0.05$ for the normal decay phase, which reinforces the idea that both phases share the same physical origin. Notably, the post-plateau data exhibit a systematic downward shift in luminosity, which may indicate the cessation of the central engine.
