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arXiv 2501.02577astro-ph.COastro-ph.GA
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通过模型无关的距离比研究透镜星系密度斜率的红移演化

Investigating the Redshift Evolution of Lensing Galaxy Density Slopes via Model-Independent Distance Ratios

Shuaibo Geng, Margherita Grespan, Hareesh Thuruthipilly, Sreekanth Harikumar, Agnieszka Pollo, Marek Biesiada

AI总结:

本研究提出一种独立于暗能量模型的新方法,利用扩展幂律模型和ANN重建强透镜距离比,揭示透镜星系质量密度斜率随红移的负演化趋势,并通过模拟证明未来巡天光谱观测能大幅提升该趋势的测量精度。

摘要:

下一代巡天有望大量发现强透镜系统,为研究宇宙学和星系演化提供有力工具。星系结构与宇宙学通过距离比的联系凸显了研究透镜星系质量密度轮廓演化的必要性。我们提出一种新颖的、独立于暗能量模型的方法,使用扩展幂律(EPL)模型研究透镜星系的质量密度斜率及其红移演化。我们采用基于人工神经网络(ANNs)的非参数方法,利用Ia型超新星(SNIa)数据训练ANNs,以重建强透镜系统的距离比。将这些比率与理论预测进行比较,以估计EPL模型参数的演化。通过合并样本、单个透镜和分箱组三个层面的分析,确保了估计的稳健性和可靠性。观测到质量密度斜率随红移呈负趋势,在各向异性三角先验下量化为$\partialγ/\partial z = -0.20 \pm 0.12$。本研究表明,透镜星系密度斜率的红移演化可独立于暗能量模型确定。基于LSST Rubin天文台预测的模拟(预计发现100,000个强透镜)显示,仅对其中10%的系统进行光谱后续观测,就能将红移演化系数的不确定性($\Delta\partialγ/\partial z$)限制在0.021。这种精度可区分演化和非演化的密度斜率,为星系演化和宇宙学提供新见解。

英文摘要:

Strong lensing systems, expected to be abundantly discovered by next-generation surveys, offer a powerful tool for studying cosmology and galaxy evolution. The connection between galaxy structure and cosmology through distance ratios highlights the need to examine the evolution of lensing galaxy mass density profiles. We propose a novel, dark energy-model-independent method to investigate the mass density slopes of lensing galaxies and their redshift evolution using an extended power-law (EPL) model. We employ a non-parametric approach based on Artificial Neural Networks (ANNs) trained on Type Ia Supernovae (SNIa) data to reconstruct distance ratios of strong lensing systems. These ratios are compared with theoretical predictions to estimate the evolution of EPL model parameters. Analyses conducted at three levels, including the combined sample, individual lenses, and binned groups, ensure robust and reliable estimates. A negative trend in the mass density slope with redshift is observed, quantified as $\partialγ/\partial z = -0.20 \pm 0.12$ under a triangular prior for anisotropy. This study demonstrates that the redshift evolution of density slopes in lensing galaxies can be determined independently of dark energy models. Simulations based on LSST Rubin Observatory forecasts, which anticipate 100,000 strong lenses, show that spectroscopic follow-up of just 10 percent of these systems can constrain the redshift evolution coefficient with uncertainty ($Δ\partialγ/\partial z$) to 0.021. This precision distinguishes evolving and non-evolving density slopes, providing new insights into galaxy evolution and cosmology.

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