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Related papers: Multi log-normal density structure in Cygnus-X mol…

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We present the detection analysis of a diffuse molecular cloud at z$_{abs}$=2.4636 towards the quasar SDSS J1513+0352(z$_{em}\,\simeq$ 2.68) observed with the X-shooter spectrograph(VLT). We measure very high column densities of atomic and…

High-angular resolution observations of dense molecular cores show that these cores can be clumpier at smaller scales, and that some of these clumps can also be unbound or transient. The use of chemical models of the evolution of the…

Astrophysics of Galaxies · Physics 2015-06-05 Oscar Morata , Josep Miquel Girart , Robert Estalella , Robin T. Garrod

To understand the impact of low metallicities on giant molecular cloud (GMC) structure, we compare far infrared dust emission, CO emission, and dynamics in the star-forming complex N83 in the Wing of the Small Magellanic Cloud. Dust…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-12 A. K. Leroy , A. Bolatto , C. Bot , C. W. Engelbracht , K. Gordon , F. P. Israel , M. Rubio , K. Sandstrom , S. Stanimirović

Using a suite of self-similar cosmological simulations, we measure the probability distribution functions (PDFs) of real-space density, redshift-space density, and their geometric mean. We find that the real-space density PDF is…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-27 Huanqing Chen , Nickolay Y. Gnedin , Philip Mansfield

We compute the one-point PDF of an initially Gaussian dark matter density field using spherical collapse (SC). We compare the results to other forms available in the literature and also compare the PDFs in the $\Lambda$CDM model with an…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-08 Ankush Mandal , Sharvari Nadkarni-Ghosh

We introduce the concept of a class of equivalence of molecular clouds represented by an abstract spherically symmetric, isotropic object. This object is described by use of abstract scales in respect to a given mass density distribution.…

Astrophysics of Galaxies · Physics 2017-01-18 Sava Donkov , Todor V. Veltchev , Ralf S. Klessen

The Cygnus-X complex is a massive, nearby (1.4 kpc) star-forming region with several OB associations. As part of the Cygnus Allscale Survey of Chemistry and Dynamical Environments (CASCADE) program, we carried out 3.6 millimeter (mm)…

To investigate whether disk-mediated accretion is the primary mechanism in high-mass star formation, we have established a survey of a large sample of massive dense cores within a giant molecular cloud. We used high angular resolution…

Astrophysics of Galaxies · Physics 2024-01-01 Xing Pan , Keping Qiu , Kai Yang , Yue Cao , Xu Zhang

Recent observations of column densities in molecular clouds find lognormal distributions with power-law high-density tails. These results are often interpreted as indications that supersonic turbulence dominates the dynamics of the observed…

Astrophysics of Galaxies · Physics 2015-05-19 K. Tassis , D. A. Christie , A. Urban , J. L. Pineda , T. Ch. Mouschovias , H. W. Yorke , H. Martel

We have analyzed HCN(1-0) and CS(2-1) line profiles obtained with high signal-to-noise ratios toward distinct positions in three selected objects in order to search for small-scale structure in molecular cloud cores associated with regions…

Astrophysics of Galaxies · Physics 2011-08-31 L. E. Pirogov , I. I. Zinchenko

We present the detection of the average H$_2$ absorption signal in the overall population of neutral gas absorption systems at $z\sim 3$ using composite absorption spectra built from the Sloan Digital Sky Survey-III damped Lyman-$\alpha$…

Astrophysics of Galaxies · Physics 2018-05-02 Sergei Balashev , Pasquier Noterdaeme

Using the Plateau de Bure interferometer, we observed the 3mm absorption lines of CN, HCN and HNC from some of the diffuse clouds which lie toward our well-studied sample of compact extragalactic mm-wave continuum sources. The column…

Astrophysics · Physics 2009-11-06 H. Liszt , R. Lucas

We examine several different simplified approaches for modelling the chemistry of CO in three-dimensional numerical simulations of turbulent molecular clouds. We compare the different models both by looking at the behaviour of integrated…

Astrophysics of Galaxies · Physics 2015-05-27 S. C. O. Glover , P. C. Clark

After the morphological classification of the 18,190 $^{12}$CO molecular clouds, we further investigate the properties of their internal molecular gas structures traced by the $^{13}$CO($J=$ 1$-$0) line emissions. Using three different…

Astrophysics of Galaxies · Physics 2022-08-17 Lixia Yuan , Ji Yang , Fujun Du , Yang Su , Xunchuan Liu , Shaobo Zhang , Yan Sun , Xin Zhou , Qing-Zeng Yan , Yuehui Ma

We investigate how the X factor, the ratio of H_2 column density (NH2) to velocity-integrated CO intensity (W), is determined by the physical properties of gas in model molecular clouds (MCs). We perform radiative transfer calculations on…

Astrophysics of Galaxies · Physics 2015-05-27 Rahul Shetty , Simon C. Glover , Cornelis P. Dullemond , Eve C. Ostriker , Andrew I. Harris , Ralf S. Klessen

Based on the analysis of available published data and archival data along 24 sightlines (5 of which are new) we derive more accurate estimates of the column densities of OH and CH towards diffuse/translucent clouds and revisit the typically…

Astrophysics of Galaxies · Physics 2016-04-20 Bhaswati Mookerjea

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…

We use techniques from nonparametric function estimation theory to extract the density profiles, and their derivatives, from a set of N-body dark matter halos. We consider halos generated from LCDM simulations of gravitational clustering,…

Astrophysics · Physics 2012-04-26 David Merritt , Alister W. Graham , Ben Moore , Juerg Diemand , Balsa Terzic