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We mapped five massive star forming regions with the SCUBA-2 camera on the James Clerk Maxwell Telescope (JCMT). Temperature and column density maps are obtained from the SCUBA-2 450 and 850 $\mu$m images. Most of the dense clumps we find…

Seven Class 0 sources mapped with SCUBA at 850 and 450 micron are modeled using a one dimensional radiative transfer code. The modeling takes into account heating from an internal protostar, heating from the ISRF, realistic beam effects,…

Astrophysics · Physics 2009-09-28 Yancy L. Shirley , Neal J. Evans , Jonathan M. C. Rawlings

We present an evaluative study of some current methods utilized in the analysis of infrared (IR) observatinons of star-forming regions. A series of self-consistent radiative transfer models are constructed, with the outputs analysed using…

Astrophysics · Physics 2007-05-23 S. D. Doty , M. L. Palotti

An improved formulation for the X-factor is proposed. The statement that the velocity-integrated radiation temperature of the $\COone$ line, $I(\CO)$, ``counts'' optically thick clumps is quantified using the formalism of \citet{Martin84}…

Astrophysics · Physics 2008-11-26 W. F. Wall

The stellar mass spectrum is an important property of the stellar cluster and a fundamental quantity to understand our Universe. The fragmentation of diffuse molecular cloud into stars is subject to physical processes such as gravity,…

Astrophysics of Galaxies · Physics 2019-02-13 Yueh-Ning Lee , Patrick Hennebelle

We use photometric data, from the optical to the mm for a large sample of optically selected radio-quiet quasars, at low and high redshifts, to test emission models from circum-nuclear dusty torii around them. Model parameters, such as dust…

Astrophysics · Physics 2007-05-23 P. Andreani , A. Franceschini , G. L. Granato

Direct imaging has paved the way for atmospheric characterization of young and self-luminous gas giants. Scattering in a horizontally-inhomogeneous atmosphere causes the disk-integrated polarization of the thermal radiation to be linearly…

Earth and Planetary Astrophysics · Physics 2018-11-09 Tomas Stolker , Michiel Min , Daphne M. Stam , Paul Mollière , Carsten Dominik , Rens Waters

Several galaxies, such as dwarfs and Irregulars as well as outer galactic clouds have low metallicity. At low metallicities a reduction in the amount of dust and heavy elements plays a significant role on the chemistry as well as the…

Astrophysics · Physics 2007-05-23 S. Jeyakumar , J. Stutzki

Tori of Active Galactic Nuclei are made up of a mixture of hot and cold gas, as well as dust. In order to protect the dust grains from destruction by the hot gas as well as by the energetic radiation of the accretion disk, the dust is often…

Astrophysics · Physics 2009-11-13 M. Schartmann , K. Meisenheimer , M. Camenzind , S. Wolf , K. R. W. Tristram , Th. Henning

$\mathit{Context.}$ The thermal conductivity of highly porous dust aggregates is a key parameter for many subjects in planetary science; however, it is not yet fully understood. $\mathit{Aims.}$ In this study, we investigate the thermal…

Earth and Planetary Astrophysics · Physics 2017-12-06 Sota Arakawa , Hidekazu Tanaka , Akimasa Kataoka , Taishi Nakamoto

We have investigated the impact of photoionization and radiation pressure on a dusty star-forming cloud using one-dimensional radiation hydrodynamic simulations, which include absorption and re-emission of photons by dust. We find that, in…

Astrophysics of Galaxies · Physics 2016-12-20 Shohei Ishiki , Takashi Okamoto

Motivated by observational and theoretical work which both suggest very small scale ($\lesssim 1\,$pc) structure in the circum-galactic medium of galaxies and in other environments, we study Lyman-$\alpha$ (Ly$\alpha$) radiative transfer in…

Astrophysics of Galaxies · Physics 2017-11-22 Max Gronke , Mark Dijkstra , Michael McCourt , S. Peng Oh

The dust cannot survive closer to the star from the point where a grain reaches a temperature equal to the sublimation temperature. The boundary between a dust-free and a dusty region defines the sublimation wall. In the literature two…

Solar and Stellar Astrophysics · Physics 2012-10-09 Erick Nagel , Paola D'Alessio , Nuria Calvet , Catherine Espaillat , Miguel Angel Trinidad

We introduce and test a new and highly efficient method for treating the thermal and radiative effects influencing the energy equation in SPH simulations of star formation. The method uses the density, temperature and gravitational…

Astrophysics · Physics 2009-11-13 D. Stamatellos , A. P. Whitworth , T. Bisbas , S. Goodwin

To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the…

Astrophysics · Physics 2011-02-11 Liubin Pan , Paolo Padoan

The formation and evolution of clusters of galaxies are sensitive to the underlying cosmological model. Constraints on cosmological parameters of cold dark matter models have been derived from mass, temperature and luminosity functions of…

Astrophysics · Physics 2007-05-23 S. M. Molnar , K. Jahoda

The accepted explanation of the observed dichotomy of two orders of magnitude between in situ measurements of electron density in HII regions, derived from emission line ratios, and average measurements based on integrated emission measure,…

Astrophysics · Physics 2016-08-16 C. Giammanco , J. E. Beckman , A. Zurita , M. Relaño

OB star clusters originate from parsec-scale massive molecular clumps. We aim to understand the evolution of temperature and density structures on the intermediate-scale ($\lesssim$0.1-1 pc) extended gas of massive clumps. We performed…

We study the thermal evolution of primordial star-forming gas clouds using three-dimensional cosmological simulations. We critically examine how assumptions and approximations made in calculating radiative cooling rates affect the dynamics…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-20 Shingo Hirano , Naoki Yoshida

Our aim is to compare the infrared properties of big, ``classical'' dust grains with visual extinction in the cloud L1642. In particular, we study the differences of grain emissivity between diffuse and dense regions in the cloud. The…

Astrophysics · Physics 2009-11-13 K. Lehtinen , M. Juvela , K. Mattila , D. Lemke , D. Russeil