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Pillars and globules are present in many high-mass star-forming regions, such as the Eagle nebula (M16) and the Rosette molecular cloud, and understanding their origin will help characterize triggered star formation. The formation…

We present new observations of a 2' field in the north-eastern spiral arm of M31. In the 0.8 x 3.6 kpc mosaicked region, we have detected six distinct, large complexes of molecular gas, most of which lie along the spiral arm dust lane or in…

Astrophysics · Physics 2007-05-23 Kartik Sheth , Stuart N. Vogel , Christine D. Wilson , T. M. Dame

The skeleton formalism aims at extracting and quantifying the filamentary structure of the universe is generalized to 3D density fields; a numerical method for computating a local approximation of the skeleton is presented and validated…

Astrophysics · Physics 2009-11-13 T. Sousbie , C. Pichon , S. Colombi , D. Novikov , D. Pogosyan

An important aspect of astrophysical MHD turbulence research is developing diagnostics to connect simulations with the observable universe. Turbulent systems are by definition structurally complex in all fluid variables (density, velocity,…

Astrophysics · Physics 2007-05-23 Eve C. Ostriker

The formation of stars is inextricably linked to the structure of their parental molecular clouds. Here we take a number of nearby giant molecular clouds (GMCs) and analyse their column density and mass distributions. This investigation is…

Astrophysics of Galaxies · Physics 2015-05-18 D. Froebrich , J. Rowles

We have developed a code that models the formation, destruction, radiative transfer, and vibrational/rotational excitation of H_2 in a detailed fashion. We discuss how such codes, together with FUSE observations of H_2 in diffuse and…

Astrophysics · Physics 2009-11-07 Matthew K. Browning , Jason Tumlinson , J. Michael Shull

To complement the optical absorption-line survey of diffuse molecular gas in Paper I, we obtained and analyzed far ultraviolet H$_2$ and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column…

Astrophysics · Physics 2009-11-13 K. Pan , S. R. Federman , Y. Sheffer , B. -G. Andersson

We develop an analysis pipeline for characterizing the topology of large scale structure and extracting cosmological constraints based on persistent homology. Persistent homology is a technique from topological data analysis that quantifies…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-14 Matteo Biagetti , Alex Cole , Gary Shiu

The kinematics of molecular gas are crucial for setting the stage for star formation. One key question related to the kinematic properties of gas is how they depend on the spatial scale. We aim to describe the CO spectra, velocity…

Astrophysics of Galaxies · Physics 2022-11-16 Andri Spilker , Jouni Kainulainen , Jan Orkisz

In this work we introduce the curvature of a galaxy brightness profile to identify its structural subcomponents in a non-parametrically fashion. Bulges, bars, disks, lens, rings and spiral arms are key to understand the formation and…

Astrophysics of Galaxies · Physics 2019-08-06 Geferson Lucatelli , Fabricio Ferrari

In order to understand how molecular clouds form in the Galactic interstellar medium, we would like to be able to map the structure and kinematics of the gas flows responsible for forming them. However, doing so is observationally…

Astrophysics of Galaxies · Physics 2016-06-01 Simon C. O. Glover , Paul C. Clark

We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well defined spatial properties, we calibrate the method and test its limitations to ultimately apply…

Solar and Stellar Astrophysics · Physics 2016-01-13 T. G. Arshakian , V. Ossenkopf

The mass of molecular gas in an interstellar cloud is often measured using line emission from low rotational levels of CO, which are sensitive to the CO mass, and then scaling to the assumed molecular hydrogen H_2 mass. However, a…

Astrophysics of Galaxies · Physics 2015-05-18 Mark G. Wolfire , David Hollenbach , Christopher F. McKee

We use detailed numerical simulations of the coupled chemical, thermal and dynamical evolution of the gas in a turbulent molecular cloud to study the usefulness of the [CI] 609 micron and 370 micron fine structure emission lines as tracers…

Astrophysics of Galaxies · Physics 2015-06-19 Simon C. O. Glover , Paul C. Clark , Milica Micic , Faviola Molina

We present a method for finding high density, low-dimensional structures in noisy point clouds. These structures are sets with zero Lebesgue measure with respect to the $D$-dimensional ambient space and belong to a $d<D$ dimensional space.…

We propose and investigate a new algorithm for quantifying the topological properties of cosmological density fluctuations. We first motivate this algorithm by drawing a formal distinction between two definitions of relevant topological…

Astrophysics · Physics 2015-06-24 Peter Coles , Andrew G. Davies , Russell C. Pearson

It is proposed to search for scintillation of extragalactic sources through the last unknown baryonic structures. Appropriate observation of the scintillation process described here should allow one to detect column density stochastic…

Astrophysics · Physics 2007-05-23 Marc Moniez

We model the temperature and chemical structure of molecular clouds as a function of depth into the cloud, assuming a cloud of constant density n illuminated by an external FUV (6 eV < E < 13.6 eV) flux G_0 (scaling factor in multiples of…

Astrophysics · Physics 2011-02-11 David Hollenbach , Michael J. Kaufman , Edwin A. Bergin , Gary J. Melnick

We use the COMPLETE Survey's observations of the Perseus star-forming region to assess and intercompare three methods for measuring column density in molecular clouds: extinction mapping (NIR); thermal emission mapping (FIR); and mapping…

Astrophysics · Physics 2011-02-11 Alyssa A. Goodman , Jaime E. Pineda , Scott L. Schnee

It is of great interest to measure the properties of substructures in dark matter halos at galactic and cluster scales. Here we suggest a method to constrain substructure properties using the variance of weak gravitational flexion in a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 D. J. Bacon , A. Amara , J. I. Read