论文标题
GRB 220426a：热辐射主导的伽马射线爆发
GRB 220426A: A Thermal Radiation-Dominated Gamma-Ray Burst
论文作者
论文摘要
伽马射线爆发（GRB）射出的物理组成仍然是一个悬而未决的问题。及时伽马射线的辐射机制也在争论中。可以解决托有不同热辐射的爆发问题。但是，具有主要的热光谱成分的事件仍然很少见。在这项工作中，我们专注于GRB 220426a，这是Fermi-GBM最近检测到的事件。时间分辨和时间整合的数据分析产生非常硬的低能光谱指数和相当柔软的高能光谱指数。这意味着GRB 220426A的光谱被狭窄分布。贝叶斯推论结果有利于多色黑体（MBB）模型。计算相对论流出的物理特性。假设有红移$ z = 1.4 $，则发现大量的lorentz因子$γ$在$ 274 _ { - 18}^{+24} $和$ 827 _ { - 71}^{+100} $之间$ 1.83 _ { - 0.50}^{+0.52} \ times 10^{11} $和$ 2.97 _ { - 0.15}^{+0.14} \ times 10^{12} $ cm。类似于GRB 090902B，GRB 220426A的时间分辨属性满足观察到的$γ-L $和$ e_p-l $相关性，其中$ l $是及时发射的发光度，而$ e_ {p} $是光谱峰值能量。
The physical composition of the ejecta of gamma-ray bursts (GRBs) remains an open question. The radiation mechanism of the prompt gamma rays is also in debate. This problem can be solved for the bursts hosting distinct thermal radiation. However, the events with dominant thermal spectral components are still rare. In this work, we focus on GRB 220426A, a recent event detected by Fermi-GBM. The time-resolved and time-integrated data analyses yield very hard low-energy spectral indices and rather soft high-energy spectral indices. This means that the spectra of GRB 220426A are narrowly distributed. And the Bayesian inference results are in favor of the multicolor blackbody (mBB) model. The physical properties of the relativistic outflow are calculated. Assuming a redshift $z= 1.4$, the bulk Lorentz factors $Γ$ of the shells are found to be between $274_{-18}^{+24}$ and $827_{-71}^{+100}$, and the corresponding photosphere radii $R_{\rm ph}$ are in the range of $1.83_{-0.50}^{+0.52} \times 10^{11}$ and $2.97_{-0.15}^{+0.14} \times 10^{12}$ cm. Similar to GRB 090902B, the time-resolved properties of GRB 220426A satisfy the observed $Γ-L$ and $E_p-L$ correlations, where $L$ is the luminosity of the prompt emission and $E_{p}$ is the spectral peak energy.
