论文标题
来自特殊的长期GRB 211211a的热和非热发射
Thermal and nonthermal emission from a peculiar long-duration GRB 211211A
论文作者
论文摘要
在如此低的红移$ z = 0.076 $的情况下，缺乏超新星发射的长期GRB 211211a甚至降至非常严格的限制，并且与Kilonova发射有关，这表明其物理起源来自二进制紧凑型星星合并。通过在费米任务上使用伽马射线爆发显示器观察到的数据，我们发现可以通过使用2SBPL加上黑体（2SBPL+bb）模型在及时发射中对时间整合和时间分辨的光谱进行拟合。可以通过调用纯火球模型中Photosphere Radius处观察到的热排放来推断出流出的大量Lorentz因子（$γ_ {\ rm pH} $），我们发现$γ_ {\ rm ph} $的时间进化似乎是与光率的跟踪。 $γ_ {\ rm pH} $的派生值也与$γ_ {\ rm ph} $ - $ l_ {γ，\ rm iso} $/$ e_ {γ，\ rm iso iso} $相关性。此外，我们还计算了中央引擎中的磁化因子$σ_{0} $，在Hybrid Jet模型的框架内的Photosphere Radius处的$σ_{\ rm ph} $计算了$σ_{\ rm ph} $，并发现两个$ 1+σ_ {\ rm 0} $和$ 1+1+σ_} $ ph的值，$ 1+σ_ {\ rm 0} $} $ ph。这表明至少在流出中确实存在Poynting-Flux组件。如果是这种情况，则GRB 211211a中热和非热分排放的一种可能的物理解释来自$ν\barν$ nihihihitation和相对论喷气机中的Blandford-Znajek机制，当时中央发动机中的Stellar Mass Black Hole位于中央发动机中。
Long-duration GRB 211211A that lacks a supernova emission even down to very stringent limits at such a low redshift $z=0.076$ and is associated with kilonova emission, suggests that its physical origin is from a binary compact star merger. By reanalyzing its data observed with the Gamma-Ray Burst Monitor on board the Fermi mission, we find that both time-integrated and time-resolved spectra can be fitted well by using a 2SBPL plus blackbody (2SBPL+BB) model in the prompt emission. The bulk Lorentz factors ($Γ_{\rm ph}$) of the outflow can be inferred by invoking the observed thermal emission at the photosphere radius within a pure fireball model, and we find out that the temporal evolution of $Γ_{\rm ph}$ seems to be tracking with the light curve. The derived values of $Γ_{\rm ph}$ are also consistent with the $Γ_{\rm ph}$-$L_{γ, \rm iso}$/$E_{γ, \rm iso}$ correlations that had been found in other bursts. Moreover, we also calculate the magnetization factor $σ_{0}$ in the central engine and $σ_{\rm ph}$ at the photosphere radius within the framework of a hybrid jet model, and find that the values of both $1+σ_{\rm 0}$ and $1+σ_{\rm ph}$ are larger than 1 for different time slices. It suggests that at least the Poynting-flux component is indeed existent in the outflow. If this is the case, one possible physical interpretation of thermal and nonthermal emissions in GRB 211211A is from the contributions of both $ν\barν$ annihilation and the Blandford-Znajek mechanisms in the relativistic jet when a stellar mass black hole resides in the central engine.
