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标题：Morphology-assisted galaxy mass-to-light predictions using deep learning
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作者：Wouter Dobbels ; Serge Krier ; Stephan Pirson 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：624
DOI：10.1051/0004-6361/201834575
语种：English
出版社：EDP Sciences
摘要：Context. One of the most important properties of a galaxy is the total stellar mass, or equivalently the stellar mass-to-light ratio (M/L). It is not directly observable, but can be estimated from stellar population synthesis. Currently, a galaxy’sM/Lis typically estimated from global fluxes. For example, a single globalg − icolour correlates well with the stellarM/L. Spectral energy distribution (SED) fitting can make use of all available fluxes and their errors to make a Bayesian estimate of theM/L.Aims. We want to investigate the possibility of using morphology information to assist predictions ofM/L. Our first goal is to develop and train a method that only requires ag-band image and redshift as input. This will allows us to study the correlation betweenM/Land morphology. Next, we can also include thei-band flux, and determine if morphology provides additional constraints compared to a method that only usesg- andi-band fluxes.Methods. We used a machine learning pipeline that can be split in two steps. First, we detected morphology features with a convolutional neural network. These are then combined with redshift, pixel size andg-band luminosity features in a gradient boosting machine. Our training target was theM/Lacquired from the GALEX-SDSS-WISE Legacy Catalog, which uses global SED fitting and contains galaxies withz ∼ 0.1.Results. Morphology is a useful attribute when no colour information is available, but can not outperform colour methods on its own. When we combine the morphology features with globalg- andi-band luminosities, we find an improved estimate compared to a model which does not make use of morphology.Conclusions. While our method was trained to reproduce global SED fittedM/L, galaxy morphology gives us an important additional constraint when using one or two bands. Our framework can be extended to other problems to make use of morphological information.
关键词：engalaxies: fundamental parametersgalaxies: stellar content