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Turbulence dissipation is an important process affecting the energy balance in molecular clouds, the birth place of stars. Previously, the rate of turbulence dissipation is often estimated with semi-analytic formulae from simulation.…

Instrumentation and Methods for Astrophysics · Physics 2018-10-10 Lei Qian , Di Li , Yang Gao , Haitao Xu , Zhichen Pan

[Abridged] Do some environments favor efficient conversion of molecular gas into stars? To answer this, we need to be able to estimate the H2 mass. Traditionally, this is done using CO and a few assumptions but the Herschel observations in…

We have created synthetic neutral hydrogen (HI) Galactic Plane Survey data cubes covering 90 degrees < l < 180 degrees, using a model spiral galaxy from SPH simulations and the radiative transfer code TORUS. The density, temperature and…

Astrophysics of Galaxies · Physics 2011-03-18 Kevin A. Douglas , David M. Acreman , Clare L. Dobbs , Christopher M. Brunt

Planets form in protoplanetary disks and inherit their chemical composition. It is therefore crucial to understand the disks molecular content. We aim to characterize the distribution and abundance of molecules in the disk of DG Tau. In the…

Astrophysics of Galaxies · Physics 2021-01-04 L. Podio , A. Garufi , C. Codella , D. Fedele , K. Rygl , C. Favre , F. Bacciotti , E. Bianchi , C. Ceccarelli , S. Mercimek , R. Teague , L. Testi

We develop a new method to constrain the physical conditions in the cool (~10^4 K) circumgalactic medium (CGM) from measurements of ionic column densities, by assuming that the cool CGM spans a large range of gas densities and that small…

Astrophysics of Galaxies · Physics 2016-10-26 Jonathan Stern , Joseph F. Hennawi , J. Xavier Prochaska , Jessica K. Werk

We have conducted a large-field simultaneous survey of $^{12}$CO, $^{13}$CO, and C$^{18}$O $J=1-0$ emission toward the Orion A giant molecular cloud (GMC) with a sky coverage of $\sim$ 4.4 deg$^2$ using the PMO-13.7 m millimeter-wavelength…

Astrophysics of Galaxies · Physics 2020-05-06 Yuehui Ma , Hongchi Wang , Chong Li , Ji Yang

We present a comprehensive study of the rho Ophiuchi molecular cloud that addresses aspects of the physical structure and condition of the molecular cloud and its photodissociation region (PDR) by combining far-infrared and…

We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…

Astrophysics of Galaxies · Physics 2021-01-20 Thomas G. Bisbas , Jonathan C. Tan , Kei E. I. Tanaka

We have observed 12CO J = 2-1 and J = 1-0, and 13CO J = 1-0 emission in two regions of HI Self-Absorption (HISA) in Perseus: a small, isolated HISA feature called the globule and a more extended HISA cloud called the complex. Using both…

Astrophysics · Physics 2009-11-13 P. D. Klaassen , R. Plume , S. J. Gibson , A. R. Taylor , C. M. Brunt

The relative abundances of atomic and molecular species in planet-forming disks around young stars provide important constraints on photochemical disk models and provide a baseline for calculating disk masses from measurements of trace…

Solar and Stellar Astrophysics · Physics 2015-06-22 Kevin France , Gregory J. Herczeg , Matthew McJunkin , Steven V. Penton

Normal field stars located behind dense clouds are a valuable resource in interstellar astrophysics, as they provide continua in which to study phenomena such as gas-phase and solid-state absorption features, interstellar extinction and…

Astrophysics · Physics 2009-06-23 S. S. Shenoy , D. C. B. Whittet , J. A. Ives , D. M. Watson

We performed single point [C I] $^3$P$_1$-$^3$P$_0$ and CO J=4-3 observations toward three T Tauri stars, DM Tau, LkCa 15, and TW Hya, using the Atacama Large Millimeter/submillimeter Array (ALMA) Band 8 qualification model receiver…

Solar and Stellar Astrophysics · Physics 2015-06-24 Takashi Tsukagoshi , Munetake Momose , Masao Saito , Yoshimi Kitamura , Yoshito Shimajiri , Ryohei Kawabe

Using observed GALEX far-ultraviolet (FUV) fluxes and VLA images of the 21-cm HI column densities, along with estimates of the local dust abundances, we measure the volume densities of a sample of actively star-forming giant molecular…

Astrophysics · Physics 2009-11-13 Jonathan S. Heiner , Ronald J. Allen , O. Ivy Wong , Pieter C. van der Kruit

We investigate the physical structure of the gas component of the disk around the pre-main-sequence star HD169142. The 13CO and C18O J=2-1 line emission is observed from the disk with 1.4'' resolution using the Submillimeter Array. We adopt…

Astrophysics · Physics 2008-06-12 Olja Panić , Michiel R. Hogerheijde , David Wilner , Chunhua Qi

Recent submillimeter and far-infrared wavelength observations of absorption in the rotational ground-state lines of various simple molecules against distant Galactic continuum sources have opened the possibility of studying the chemistry of…

Astrophysics of Galaxies · Physics 2017-02-21 B. Winkel , H. Wiesemeyer , K. M. Menten , M. Sato , A. Brunthaler , F. Wyrowski , D. Neufeld , M. Gerin , N. Indriolo

We have observed five sulphur-bearing molecules in foreground diffuse molecular clouds lying along the sight-lines to five bright continuum sources. We have used the GREAT instrument on SOFIA to observe the 1383 GHz $^2\Pi_{3/2} J=5/2-3/2$…

We present a survey of the Perseus molecular cloud in the J $=$ 1$\rightarrow$0 transition of HCN, a widely used tracer of dense molecular gas. The survey was conducted with the CfA 1.2 m telescope, which at 89 GHz has a beam width of 11'…

Astrophysics of Galaxies · Physics 2023-03-08 T. M. Dame , Charles J. Lada

The Delta-variance analysis is an efficient tool for measuring the structural scaling behaviour of interstellar turbulence in astronomical maps. In paper I we proposed essential improvements to the Delta-variance analysis. In this paper we…

Astrophysics · Physics 2009-11-13 V. Ossenkopf , M. Krips , J. Stutzki

The nature of the gaseous and dusty cloud G2 in the Galactic Centre is still under debate. We present three-dimensional hydrodynamical adaptive mesh refinement (AMR) simulations of G2, modeled as an outflow from a "compact source" moving on…

Astrophysics of Galaxies · Physics 2018-06-13 A. Ballone , M. Schartmann , A. Burkert , S. Gillessen , P. M. Plewa , R. Genzel , O. Pfuhl , F. Eisenhauer , M. Habibi , T. Ott , E. M. George

We present a study of the chemistry of a dense photon-dominated region (PDR) using a time-dependent chemical model. Our major interest is to study the spatial distribution of complex molecules such as hydrocarbons and cyanopolyynes in the…

Astrophysics · Physics 2009-11-13 O. Morata , E. Herbst