2018/08/16 by Kenji Bekki · 7 citations
Physics and Astronomy · #Artificial intelligence #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Brightest cluster galaxy #Cluster (spacecraft) #Computer science #Convolutional neural network #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy formation and evolution #Galaxy group #Hydrostatic equilibrium #Physics #Ram pressure #Star formation #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.IM
paper · pdf · open access · doi:10.1093/mnras/sty2203
published in Monthly Notices of the Royal Astronomical Society 485(2), 1924-1937 (Oxford University Press) · 15 pages, 13 figures, published in MNRAS (tmp)
openalex publication_date 2018/08/16 · arxiv created 2018/11/12 · arxiv updated 2018/11/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Ram pressure stripping (RPS) of gas from disc galaxies has long been considered to play vital roles in galaxy evolution within groups and clusters. For a given density of intracluster medium (ICM) and a given velocity of a disc galaxy, RPS can be controlled by two angles (θ and ϕ) that define the angular relationship between the direction vector of the galaxy’s three-dimensional (3D) motion within its host cluster and the galaxy’s spin vector. We here propose a new method in which convolutional neutral networks (CNNs) are used to constrain θ and ϕ of disc galaxies under RPS. We first train a CNN by using ∼105 synthesized images of gaseous distributions of the galaxies from numerous RPS models with different θ and ϕ. We then apply the trained CNN to a new test RPS model to predict θ and ϕ. The similarity between the correct and predicted θ and ϕ is measured by cosine similarity (cos Θ) with cos Θ = 1 being perfectly accurate prediction. We show that the average cos Θ among test models is ≈0.95 (≈18° deviation), which means that θ and ϕ can be constrained by applying the CNN to the gaseous distributions. This result suggests that if the ICM is in hydrostatic equilibrium (thus not moving), the 3D orbit of a disc galaxy within its host cluster can be constrained by the spatial distribution of the gas being stripped by RPS. We discuss how this new method can be applied to H i studies of galaxies by ongoing and future large H i surveys such as the WALLABY and the SKA projects.