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Related papers: Optically Thick Clumps - Not the Solution to the W…

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We investigate the mass function of cold, dusty clumps in 11 low- and high-mass star-forming regions. Using a homogeneous fitting technique, we analyze the shape of each region's clump mass function and examine the commonalities among them.…

Astrophysics · Physics 2008-11-26 Michael A. Reid , Christine D. Wilson

High brightness temperature radio transients such as pulsars and fast radio bursts require the coherent radiation of particles. The antenna class of coherent radiation models require a large number of charged particles radiating in phase,…

High Energy Astrophysical Phenomena · Physics 2021-08-25 A. J. Cooper , R. A. M. J. Wijers

We present a generalised formalism for treating the porosity-associated reduction in continuum opacity that occurs when individual clumps in a stochastic medium become optically thick. We consider geometries resulting in either isotropic or…

Solar and Stellar Astrophysics · Physics 2015-06-03 Jon O. Sundqvist , Stanley P. Owocki , David H. Cohen , Maurice A. Leutenegger , Richard H. D. Townsend

Infrared imaging of the colliding-wind binary Apep has revealed a spectacular dust plume with complicated internal dynamics that challenges standard colliding-wind binary physics. Such challenges can be potentially resolved if a…

Solar and Stellar Astrophysics · Physics 2020-05-13 J. R. Callingham , P. A. Crowther , P. M. Williams , P. G. Tuthill , Y. Han , B. J. S. Pope , B. Marcote

We investigate the effects of stellar limb-darkening and photospheric perturbations for the onset of wind structure arising from the strong, intrinsic line-deshadowing instability (LDI) of a line-driven stellar wind. A linear perturbation…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jon O. Sundqvist , Stanley P. Owocki

We compare the angular momentum extracted by a wind from a pre-main-sequence star to the torques arising from the interaction between the star and its Keplerian accretion disk. We find that the wind alone can counteract the spin-up torque…

Astrophysics · Physics 2016-08-30 Sean Matt , Ralph E. Pudritz

Observations of radio loud active galaxies in the XMM-Newton archive by Mehdipour & Costantini show a strong anti-correlation between the column density of the ionized wind and the radio loudness parameter, providing evidence that jets may…

High Energy Astrophysical Phenomena · Physics 2019-05-15 David Garofalo

Wolf-Rayet stars embody the final stable phase of the most massive stars immediately before their evolution is terminated in a supernova explosion. They are responsible for some of the most extreme and energetic phenomena in stellar…

Solar and Stellar Astrophysics · Physics 2024-12-18 Ryan M. T. White , Peter Tuthill

We present the first non-LTE atmosphere models for WR stars that incorporate a self-consistent solution of the hydrodynamic equations. The models account for iron-group line-blanketing and clumping, and compute the hydrodynamic structure of…

Astrophysics · Physics 2009-11-10 G. Gräfener , W. -R. Hamann

Supersonic turbulence plays a dual role in molecular clouds: On one hand, it contributes to the global support of the clouds, while on the other it promotes the formation of small-scale density fluctuations, identifiable with clumps and…

Astrophysics · Physics 2015-11-11 Enrique Vazquez-Semadeni

Pulsar winds have longstanding problems in energy conversion and pair cascade processes which determine the magnetization $\sigma$, the pair multiplicity $\kappa$ and the bulk Lorentz factor $\gamma$ of the wind. We study induced Compton…

High Energy Astrophysical Phenomena · Physics 2013-11-22 Shuta J. Tanaka , Fumio Takahara

Wind-blown bubbles, from those around massive O and Wolf-Rayet stars, to superbubbles around OB associations and galactic winds in starburst galaxies, have a dominant role in determining the structure of the Interstellar Medium. X-ray…

Astrophysics · Physics 2009-10-30 David K. Strickland , Ian R. Stevens

The high luminosity of Very Massive Stars (VMS) means that radiative forces play an important, dynamical role both in the structure and stability of their stellar envelope, and in driving strong stellar-wind mass loss. Focusing on the…

Solar and Stellar Astrophysics · Physics 2015-06-19 Stanley P. Owocki

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

Mass-loss from massive stars is fundamental to stellar and galactic evolution and enrichment of the interstellar medium. Reliable determination of mass-loss rate is dependent upon unravelling details of massive star outflows, including…

Solar and Stellar Astrophysics · Physics 2025-12-18 Timothy N. Parsons , Raman K. Prinja , Derck L. Massa , Alex W. Fullerton

Understanding the interaction of dense, cold ejecta clumps with a fast reverse shock, an instance of the "cloud-crushing" problem, is essential to assess whether core-collapse supernovae act as net dust factories or net dust destroyers.…

Astrophysics of Galaxies · Physics 2025-10-08 Sergio Martínez-González

With Planck and Herschel, we now have the spectral coverage and angular resolution required to observe dense and cold molecular clouds. As these clouds are optically thick at short wavelength but optically thin at long wavelength, it is…

The dynamics of colliding wind binary systems and conditions for efficient particle acceleration therein have attracted multiple numerical studies in the recent years. These numerical models seek an explanation of the thermal and…

Solar and Stellar Astrophysics · Physics 2016-11-09 R. Kissmann , K. Reitberger , O. Reimer , A. Reimer , E. Grimaldo

We study the properties of luminous stellar clumps identified in deep, high resolution HST/NIC2 F160W imaging at 1.6um of six z~2 star-forming galaxies with existing near-IR integral field spectroscopy from SINFONI at the VLT. Individual…

We fit every emission line in the high-resolution Chandra grating spectrum of zeta Pup with an empirical line profile model that accounts for the effects of Doppler broadening and attenuation by the bulk wind. For each of sixteen lines or…

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