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The interstellar medium (ISM) exhibits complex, multi-scale structures that are challenging to study due to their projection into two-dimensional (2D) column density maps. We present the Volume Density Mapper, a novel algorithm based on…

Instrumentation and Methods for Astrophysics · Physics 2025-09-23 Guang-Xing Li , Mengke Zhao

We introduce the state-of-the-art deep learning Denoising Diffusion Probabilistic Model (DDPM) as a method to infer the volume or number density of giant molecular clouds (GMCs) from projected mass surface density maps. We adopt…

Astrophysics of Galaxies · Physics 2023-06-28 Duo Xu , Jonathan C. Tan , Chia-Jung Hsu , Ye Zhu

Volume density is a key physical quantity controlling the evolution of the interstellar medium (ISM) and star formation, but it cannot be accessed directly by observations of molecular clouds. We aim at estimating the volume density…

Astrophysics of Galaxies · Physics 2025-05-15 Jan H. Orkisz , Jouni Kainulainen

Modern observations of the interstellar medium (ISM) in galaxies detect a variety of atomic and molecular species. The goal is to connect these observations to the astrochemical properties of the ISM. 3D hydro-chemical simulations attempt…

Astrophysics of Galaxies · Physics 2019-02-20 Thomas G. Bisbas , Andreas Schruba , Ewine F. van Dishoeck

We present a method for modelling star-forming clouds that combines two different models of the thermal evolution of the interstellar medium (ISM). In the combined model, where the densities are low enough that at least some part of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 Matthew R. Bate , Eric R. Keto

In this paper, we outline the use of Mixture Models in density estimation of large astronomical databases. This method of density estimation has been known in Statistics for some time but has not been implemented because of the large…

Astrophysics · Physics 2007-05-23 A. J. Connolly , C. Genovese , A. W. Moore , R. C. Nichol , J. Schneider , L. Wasserman

We have developed a technique to map the three-dimensional structure of the local interstellar medium using a maximum entropy reconstruction technique. A set of column densities N to stars of known distance can in principle be used to…

Astrophysics · Physics 2009-10-31 John S. Arabadjis , Joel N. Bregman

Deconvolution of astronomical images is a key aspect of recovering the intrinsic properties of celestial objects, especially when considering ground-based observations. This paper explores the use of diffusion models (DMs) and the Diffusion…

Instrumentation and Methods for Astrophysics · Physics 2025-01-22 Alessio Spagnoletti , Alexandre Boucaud , Marc Huertas-Company , Wassim Kabalan , Biswajit Biswas

We present initial results on the use of Mixture Models for density estimation in large astronomical databases. We provide herein both the theoretical and experimental background for using a mixture model of Gaussians based on the…

Astrophysics · Physics 2007-05-23 R. C. Nichol , A. J. Connolly , A. W. Moore , J. Schneider , C. Genovese , L. Wasserman

The interstellar medium (ISM) is a turbulent, highly structured multi-phase medium. State-of-the-art cosmological simulations of the formation of galactic discs usually lack the resolution to accurately resolve those multi-phase structures.…

Astrophysics of Galaxies · Physics 2022-04-13 Tobias Buck , Christoph Pfrommer , Philipp Girichidis , Bogdan Corobean

We present a geometry-independent method for determining the shapes of radial volume density profiles of astronomical objects whose geometries are unknown, based on a single column density map. Such profiles are often critical to understand…

Astrophysics of Galaxies · Physics 2016-05-04 Marko Krčo , Paul F. Goldsmith

Accurately quantifying the impact of radiation feedback in star formation is challenging. To address this complex problem, we employ deep learning techniques, denoising diffusion probabilistic models (DDPMs), to predict the interstellar…

Astrophysics of Galaxies · Physics 2023-09-13 Duo Xu , Stella Offner , Robert Gutermuth , Michael Grudic , David Guszejnov , Philip Hopkins

AI fairness seeks to improve the transparency and explainability of AI systems by ensuring that their outcomes genuinely reflect the best interests of users. Data augmentation, which involves generating synthetic data from existing…

Machine Learning · Computer Science 2024-10-22 Christina Hastings Blow , Lijun Qian , Camille Gibson , Pamela Obiomon , Xishuang Dong

Sub-millimetre dust emission is often used to derive the column density N of dense interstellar clouds. The observations consist of data at several wavelengths but of variable resolution. We examine two procedures that been proposed for the…

Astrophysics of Galaxies · Physics 2015-06-15 M. Juvela , J. Malinen , T. Lunttila

This paper addresses the problem of generating dense point clouds from given sparse point clouds to model the underlying geometric structures of objects/scenes. To tackle this challenging issue, we propose a novel end-to-end learning-based…

Computer Vision and Pattern Recognition · Computer Science 2022-03-30 Yue Qian , Junhui Hou , Sam Kwong , Ying He

An analytical expression is presented that allows gas-to-dust elemental depletions to be estimated in interstellar environments of different types, including Damped Ly alpha systems, by scaling an arbitrary depletion pattern chosen as a…

Astrophysics · Physics 2009-11-07 Giovanni Vladilo

Star formation has long been known to be an inefficient process, in the sense that only a small fraction $\epsilon_{\rm ff}$ of the mass of any given gas cloud is converted to stars per cloud free-fall time. However, developing a successful…

Astrophysics of Galaxies · Physics 2021-02-17 Zipeng Hu , Mark R. Krumholz , Christoph Federrath , Riwaj Pokhrel , Robert A. Gutermuth

Despite low elemental abundance of atomic deuterium in interstellar medium (ISM), observational evidences suggest that several species in gas-phase and in ices could be heavily fractionated. We explore various aspects of deuterium…

Astrophysics of Galaxies · Physics 2019-02-05 Ankan Das , Liton Majumdar , Sandip K. Chakrabarti , Dipen Sahu

We leverage the 1 pc spatial resolution of the Leike et al. 2020 3D dust map to characterize the three-dimensional structure of nearby molecular clouds ($d \lesssim 400$ pc). We start by "skeletonizing" the clouds in 3D volume density space…

Constraining the physical and chemical evolution of molecular clouds is essential to our understanding of star formation. These investigations often necessitate knowledge of some local representative number density of the gas along the line…

Astrophysics of Galaxies · Physics 2025-04-02 Brandt A. L. Gaches , Michael Y. Grudić
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