arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.02474astro-ph.COastro-ph.HEgr-qchep-ph
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低和高红移GRB光度关联的比较

Reconciling low and high redshift GRB luminosity correlations

Lu Huang, Zhiqi Huang, Xiaolin Luo, Xinbo He, Yuhong Fang

摘要:

长伽马射线暴(GRB)的峰值谱能量($E_p$)和等效各向同性能量($E_{\rm iso}$)之间的相关关系,即Amati关系,常被用来约束高红移哈勃图。在假设λ冷暗物质($Λ$ CDM)宇宙学的基础上,Wang等人发现了在低红移和高红移伽玛暴样本之间的数据校准的Amati系数中存在$\gtrsim 3σ$张力。为了减少基准宇宙学的影响,我们使用基于宇宙年龄的参数化(PAge),一个几乎与模型无关的框架来追踪宇宙膨胀的历史。我们发现,对于PAge涵盖的广泛模型类别,Amati系数中的低红移和高红移张力几乎保持相同,这表明宇宙学假设并不是GRB光度相关红移演化的主要驱动因素。接下来,我们分析了由于观测通量限制的选择效应。我们发现Amati关系在$E_{\rm iso}$的能量尺度上演化得更为显著。我们通过选择性地丢弃样本来匹配低$z$和高$z$ $E_{\rm iso}$分布来消除GRB数据的偏置。在去偏置之后,低$z$和高$z$数据组之间的Amati系数很好地一致,而Amati关系的$E_{\rm iso}$依赖性的证据仍然很强。因此,伽玛暴光度关联的红移演化完全可以解释为一种选择偏差,并不意味着伽玛暴的宇宙学演化。

英文摘要:

The correlation between the peak spectra energy ($E_p$) and the equivalent isotropic energy ($E_{\rm iso}$) of long gamma-ray bursts (GRBs), the so-called Amati relation, is often used to constrain the high-redshift Hubble diagram. Assuming Lambda cold dark matter ($Λ$CDM) cosmology, Wang et al. found a $\gtrsim 3σ$ tension in the data-calibrated Amati coefficients between low- and high-redshift GRB samples. To reduce the impact of fiducial cosmology, we use the Parameterization based on cosmic Age (PAge), an almost model-independent framework to trace the cosmological expansion history. We find that the low- and high-redshift tension in Amati coefficients stays almost the same for the broad class of models covered by PAge, indicating that the cosmological assumption is not the dominant driver of the redshift evolution of GRB luminosity correlation. Next, we analyze the selection effect due to flux limits in observations. We find Amati relation evolves much more significantly across energy scales of $E_{\rm iso}$. We debias the GRB data by selectively discarding samples to match low-$z$ and high-$z$ $E_{\rm iso}$ distributions. After debiasing, the Amati coefficients agree well between low-$z$ and high-$z$ data groups, whereas the evidence of $E_{\rm iso}$-dependence of Amati relation remains to be strong. Thus, the redshift evolution of GRB luminosity correlation can be fully interpreted as a selection bias, and does not imply cosmological evolution of GRBs.

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