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We consider the general problem of fitting a parametric density model to discrete observations, taken to follow a non-homogeneous Poisson point process. This class of models is very common, and can be used to describe many astrophysical…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 Marco Lombardi , Charles J. Lada , João Alves

The unprecedented astrometry from Gaia DR2 provides us with an opportunity to study in detail molecular clouds in the solar neighbourhood. Extracting the wealth of information in these data remains a challenge, however. We have further…

Astrophysics of Galaxies · Physics 2020-11-18 Sara Rezaei Kh. , Coryn A. L. Bailer-Jones , Juan D. Soler , Eleonora Zari

A one-dimensional method for reconstructing the structure of prestellar and protostellar clouds is presented. The method is based on radiative transfer computations and a comparison of theoretical and observed intensity distributions at…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 Ya. N. Pavlyuchenkov , D. S. Wiebe , A. M. Fateeva , T. S. Vasyunina

The spatial properties of small star-clusters suggest that they may originate from a fragmentation cascade of the cloud for which there might be traces up to a few dozen of kAU. Our goal is to investigate the multi-scale spatial structure…

Astrophysics of Galaxies · Physics 2022-09-21 B. Thomasson , I. Joncour , E. Moraux , C. Crespelle , F. Motte , Y. Pouteau , T. Nony

Since molecular clouds form stars, at least some parts of them must be in a state of collapse. However, there is a long-standing debate as to whether that collapse is local, involving only a small fraction of the cloud mass, or global, with…

Astrophysics of Galaxies · Physics 2025-07-14 Mark R. Krumholz , Charles J. Lada , Jan Forbrich

We present a new method for estimating the H2 cooling rate in the optically thick regime in simulations of primordial star formation. Our new approach is based on the TreeCol algorithm, which projects matter distributions onto a spherical…

Solar and Stellar Astrophysics · Physics 2015-05-05 Tilman Hartwig , Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen , Mei Sasaki

Recent decades have seen the discovery of numerous complex materials. At the root of the complexity underlying many of these materials lies a large number of possible contending atomic- and larger-scale configurations and the intricate…

Materials Science · Physics 2023-01-30 P. Ronhovde , S. Chakrabarty , M. Sahu , K. K. Sahu , K. F. Kelton , N. Mauro , Z. Nussinov

Understanding the distribution and properties of molecular clouds is crucial for tracing the structure and evolution of the interstellar medium and the large-scale morphology of the Milky Way. Here we present an all-sky catalog of 3,345…

Astrophysics of Galaxies · Physics 2025-09-10 Tao Wang , Haibo Yuan , Bingqiu Chen , Guangxing Li , Bowen Huang , Helong Guo , Ruoyi Zhang

Spectral clustering is a powerful method for finding structure in a dataset through the eigenvectors of a similarity matrix. It often outperforms traditional clustering algorithms such as $k$-means when the structure of the individual…

Numerical Analysis · Mathematics 2019-04-26 Paola Favati , Grazia Lotti , Ornella Menchi , Francesco Romani

A numerical hydrodynamical model for the evolution of spherically symmetric collapsing clouds, designed for the calculation of the thermal structure of these objects in both the prestellar and protostellar stages of their evolution, is…

Astrophysics of Galaxies · Physics 2015-06-23 Ya. N. Pavlyuchenkov , A. G. Zhilkin , E. I. Vorobyov , A. M. Fateeva

Many materials, processes, and structures in science and engineering have important features at multiple scales of time and/or space; examples include biological tissues, active matter, oceans, networks, and images. Explicitly extracting,…

Fluid Dynamics · Physics 2021-01-12 Daniel Floryan , Michael D. Graham

Context. The combination of wideband receivers and spectrometers currently available in (sub-)millimeter observatories deliver wide- field hyperspectral imaging of the interstellar medium. Tens of spectral lines can be observed over degree…

Diffuse emission in the mid-infrared shows a wealth of structure, that lends itself to high-resolution structure analysis of the interstellar gas. A large part of the emission comes from polycyclic aromatic hydrocarbons, excited by nearby…

Astrophysics · Physics 2008-11-26 F. Heitsch , B. Whitney , R. Indebetouw , M. R. Meade , B. L. Babler , E. Churchwell , ;

We use the $\mathit{Gaia}$ DR2 distances of about 700 mid-infrared selected young stellar objects in the benchmark giant molecular cloud Orion A to infer its 3D shape and orientation. We find that Orion A is not the fairly straight…

We assemble a homogeneous database of precise and consistent determinations of effective temperature, surface gravity, projected rotational rate, and macro- and micro-turbulent velocities for over 1800 Galactic stars spanning spectral types…

Solar and Stellar Astrophysics · Physics 2025-10-01 N. Markova , M. Cantiello , L. Grassitelli

We investigate the physical properties of gas structures under feedback in the G333 complex using data of the 13CO (3-2) line in the LAsMA observation. We used the Dendrogram algorithm to identify molecular gas structures based on the…

Astrophysics of Galaxies · Physics 2024-02-14 J. W. Zhou , F. Wyrowski , S. Neupane , I. Barlach Christensen , K. M. Menten , S. H. Li , T. Liu

To understand physical properties of the interstellar medium (ISM) on various scales, we investigate it at parsec resolution on the kiloparsec scale. Here, we report on the sub-kpc scale Gas Density Histogram (GDH) of the Milky Way. The GDH…

Velocity and density structure factors are measured over a hydrodynamic range of scales in a horizontal quasi-2d fluidized granular experiment, with packing fractions $\phi\in[10%,40%]$. The fluidization is realized by vertically vibrating…

Soft Condensed Matter · Physics 2015-06-03 A. Puglisi , A. Gnoli , G. Gradenigo , A. Sarracino , D. Villamaina

We present high resolution simulations of two-fluid (ion-neutral) MHD turbulence with resolutions as large as 512^3. The simulations are supersonic and mildly sub-Alfvenic, in keeping with the conditions present in molecular clouds. Such…

Astrophysics of Galaxies · Physics 2015-06-16 Chad D. Meyer , Dinshaw S. Balsara , Blakesley Burkhart , Alex Lazarian

We introduce a model for the large-scale, global 3D structure of molecular clouds. Motivated by the morphological appearance of clouds in surface density maps, we model clouds as cylinders, with the aim of backing out information about the…

Astrophysics of Galaxies · Physics 2023-09-12 Nia Imara , John C. Forbes