论文标题
sgr a $^*$的事件地平线望远镜结果的循环量子重力测试
Tests of Loop Quantum Gravity from the Event Horizon Telescope Results of Sgr A$^*$
论文作者
论文摘要
事件范围望远镜（EHT）协作在银河中心的紧凑对象的图像是超级质量黑洞（BH）sgr a $^*$的第一个直接证据。 sgr a $^*$的阴影具有角直径$ d_ {sh} = 48.7 \ pm 7 \，μ$，与schwarzschild bh阴影直径$δ= -0.08^{+0.09} （对于VLTI和KECK质量到距离比）。 SGR A $^*$的阴影尺寸在Kerr预测的$ 〜10 \％$之内，为我们提供了另一个分析强场状态重力的工具，包括测试环路量子重力（LQG）。我们使用sgr a $^*$的阴影来限制两个动机良好的LQG旋转BH（LIRBH）模型的指标，其特征在于附加偏差参数$ L_Q $，它们在没有量子效应的情况下恢复了Kerr Spacetime（$ L_Q \ 0 $）。当通过$ l_q $增加量子效应时，阴影大小会单调增加，而形状会更加扭曲，从而使我们能够约束基本参数$ l_q $。我们使用天体物理可观察的阴影区域$ a $ a $ and Ornates $ d $来估计BH参数。它在提取有关LIRBHS的其他信息时可能很有用。尽管EHT观察结果完全排除了LIRBH-2中的虫洞区域，但两种模型中通用BHS的实质参数区域与EHT结果一致。我们发现，从SGR A $^*$ - $ L_Q \ Lessim 0.0423 $和$ L_Q \ Lessim 0.0821 $的上限$ L_Q $上的上限分别比从M87 $^*$的EHT图像中获得的那些更为严格。
The Event Horizon Telescope (EHT) collaboration's image of the compact object at the galactic center is the first direct evidence of the supermassive black hole (BH) Sgr A$^*$. The shadow of Sgr A$^*$ has an angular diameter $d_{sh}= 48.7 \pm 7\,μ$as with fractional deviation from the Schwarzschild BH shadow diameter $δ= -0.08^{+0.09}_{-0.09}\,,-0.04^{+0.09}_{-0.10}$ (for the VLTI and Keck mass-to-distance ratios). Sgr A$^*$'s shadow size is within $~10\%$ of Kerr predictions, equipping us with yet another tool to analyze gravity in the strong-field regime, including testing loop quantum gravity (LQG). We use Sgr A$^*$'s shadow to constrain the metrics of two well-motivated LQG-inspired rotating BH (LIRBH) models characterized by an additional deviation parameter $L_q$, which recover the Kerr spacetime in the absence of quantum effects ($L_q \to 0$). When increasing the quantum effects through $L_q$, the shadow size increases monotonically, while the shape gets more distorted, allowing us to constrain the fundamental parameter $L_q$. We use the astrophysical observables shadow area $A$ and oblateness $D$ to estimate the BH parameters. It may be useful in extracting additional information about LIRBHs. While the EHT observational results completely rule out the wormhole region in the LIRBH-2, a substantial parameter region of the generic BHs in both models agrees with the EHT results. We find that the upper bounds on $L_q$ obtained from the shadow of Sgr A$^*$ -- $L_q \lesssim 0.0423$ and $L_q \lesssim 0.0821$ for the two LIRBHs, respectively -- are more stringent than those obtained from the EHT image of M87$^*$.
