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arXiv 2404.03055astro-ph.GA
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模拟星系目录的发射线预测:一种来自DESI的新的可微且经验映射

Emission Line Predictions for Mock Galaxy Catalogues: a New Differentiable and Empirical Mapping from DESI

Ashod Khederlarian, Jeffrey A. Newman, Brett H. Andrews, Biprateep Dey, John Moustakas, Andrew Hearin, Stéphanie Juneau, Luca Tortorelli, Daniel Gruen, ChangHoo… 展开作者

Ashod Khederlarian, Jeffrey A. Newman, Brett H. Andrews, Biprateep Dey, John Moustakas, Andrew Hearin, Stéphanie Juneau, Luca Tortorelli, Daniel Gruen, ChangHoon Hahn, Rebecca E. A. Canning, Jessica Nicole Aguilar, Steven Ahlen, David Brooks, Todd Claybaugh, Axel de la Macorra, Peter Doel, Kevin Fanning, Simone Ferraro, Jaime Forero-Romero, Enrique Gaztañaga, Satya Gontcho A Gontcho, Robert Kehoe, Theodore Kisner, Anthony Kremin, Andrew Lambert, Martin Landriau, Marc Manera, Aaron Meisner, Ramon Miquel, Eva-Maria Mueller, Andrea Muñoz-Gutiérrez, Adam Myers, Jundan Nie, Claire Poppett, Francisco Prada, Mehdi Rezaie, Graziano Rossi, Eusebio Sanchez, Michael Schubnell, Joseph Harry Silber, David Sprayberry, Gregory Tarlé, Benjamin Alan Weaver, Zhimin Zhou, Hu Zou

AI总结:

提出一种基于JAX的可微神经网络,利用DESI数据从星系光学连续谱预测发射线等值宽度,能整合至恒星合成流水线以改进LSST等巡天的系统误差建模。

摘要:

我们提出了一种简单、可微的方法,使用经验确定的映射从静止系光学连续谱预测发射线强度。在开发包含稳健星系测光预测的模拟星系目录方面已经进行了大量工作,但可靠地预测发射线强度仍然具有挑战性。我们的新映射是一个使用JAX Python自动微分库实现的简单神经网络。它在Dark Energy Spectroscopic Instrument Early Release数据上进行训练,以从星系的静止系光学连续谱预测八条最亮光学发射线(包括H$α$、H$β$、[O II]和[O III])的等值宽度(EWs)。当考虑噪声时,预测的EW分布与观测到的分布一致,我们发现大多数谱线的预测与观测之间的Spearman秩相关系数$ρ_s > 0.87$。使用非线性降维技术(UMAP),我们表明这对于具有全范围观测光谱能量分布的星系都是成立的。此外,我们发现,将测量不确定性添加到预测的谱线强度中,对于在BPT图中再现观测到的谱线比率分布至关重要。我们训练的网络可以轻松地合并到可微恒星种群合成流水线中,而不会阻碍GPU的可微性或可扩展性。使用这种流水线生成的合成目录可用于表征和解决用于训练和校准photo-$z$的光谱训练集中的偏差,从而改进Rubin Observatory LSST和其他巡天的系统不完整性建模。

英文摘要:

We present a simple, differentiable method for predicting emission line strengths from rest-frame optical continua using an empirically-determined mapping. Extensive work has been done to develop mock galaxy catalogues that include robust predictions for galaxy photometry, but reliably predicting the strengths of emission lines has remained challenging. Our new mapping is a simple neural network implemented using the JAX Python automatic differentiation library. It is trained on Dark Energy Spectroscopic Instrument Early Release data to predict the equivalent widths (EWs) of the eight brightest optical emission lines (including H$α$, H$β$, [O II], and [O III]) from a galaxy's rest-frame optical continuum. The predicted EW distributions are consistent with the observed ones when noise is accounted for, and we find Spearman's rank correlation coefficient $ρ_s > 0.87$ between predictions and observations for most lines. Using a non-linear dimensionality reduction technique (UMAP), we show that this is true for galaxies across the full range of observed spectral energy distributions. In addition, we find that adding measurement uncertainties to the predicted line strengths is essential for reproducing the distribution of observed line-ratios in the BPT diagram. Our trained network can easily be incorporated into a differentiable stellar population synthesis pipeline without hindering differentiability or scalability with GPUs. A synthetic catalogue generated with such a pipeline can be used to characterise and account for biases in the spectroscopic training sets used for training and calibration of photo-$z$'s, improving the modelling of systematic incompleteness for the Rubin Observatory LSST and other surveys.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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