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Related papers: Rethinking the N(H2)/I(CO) Conversion Factor

200 papers

We want to characterize the properties of the cold dust clumps in the Carina Nebula Complex (CNC), which shows a very high level of massive star feedback. We derive the Clump Mass Function (ClMF), explore the reliability of different clump…

Astrophysics of Galaxies · Physics 2015-06-12 Stephanie Pekruhl , Thomas Preibisch , Frederic Schuller , Karl Menten

We estimate the conversion factor relating CO emission to H2 mass, alpha_CO, in five Local Group galaxies that span approximately an order of magnitude in metallicity - M31, M 33, the Large Magellanic Cloud (LMC), NGC 6822, and the Small…

Context. Obtaining precise stellar and wind properties and abundance patterns of massive stars is crucial to understanding their nature and interactions with their environments, as well as to constrain their evolutionary paths and…

Solar and Stellar Astrophysics · Physics 2020-11-05 J. Puls , F. Najarro , J. O. Sundqvist , K. Sen

A multifactor parameterization is described to permit the efficient calculation of collision efficiency (E) between electrically charged aerosol particles and neutral cloud droplets in numerical cloud and climate models. The four parameter…

Atmospheric and Oceanic Physics · Physics 2015-10-28 S. N. Tripathi , S. Vishnoi , S. Kumar , R. G. Harrison

We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…

We present a simple, semianalytical approach to compute the line emission of C+, C and CO in Photodissociation Regions of varying metallicity that depends on very few parameters and naturally incorporates the clumpiness of the interstellar…

Astrophysics · Physics 2009-10-31 Alberto D. Bolatto , James M. Jackson , James G. Ingalls

Recent observations with the Submillimeter Wave Astronomy Satellite indicate abundances of gaseous H2O and O2 in dense molecular clouds which are significantly lower than found in standard homogeneous chemistry models. We present here…

Astrophysics · Physics 2009-10-31 Marco Spaans , Ewine van Dishoeck

We have used archival far-ultraviolet spectra from observations made by HST/STIS and FUSE to determine the column densities and rotational excitation temperatures for CO and H2, respectively, along the lines of sight to 23 Galactic O and B…

Astrophysics · Physics 2009-01-19 Eric B. Burgh , Kevin France , Stephan R. McCandliss

We report a Fermi-LAT $\gamma$-ray analysis for the Chamaeleon molecular-cloud complex using a total column density (NH) model based on the dust optical depth at 353 GHz ($\tau_{353}$) with the Planck thermal dust emission model. Gamma rays…

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

Context. Current implementations of mass loss for hot, massive stars in stellar evolution models include a sharp increase in mass loss when blue supergiants become cooler than Teff 20-22kK. This drastic mass-loss jump has been motivated by…

Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical…

Solar and Stellar Astrophysics · Physics 2015-05-27 J. O. Sundqvist , J. Puls , A. Feldmeier , S. P. Owocki

Column density (N) PDFs serve as a powerful tool to characterize the physical processes that influence the structure of molecular clouds. Star-forming clouds can best be characterized by lognormal PDFs for the lower N range and a power-law…

The dissipation of turbulent gas motions is one of the likely mechanisms that has been proposed to heat the intracluster medium (ICM) in the cores of clusters and groups of galaxies. We consider the impact of gas motions on the width of the…

Astrophysics · Physics 2007-11-28 P. Rebusco , E. Churazov , R. A. Sunyaev , H. Boehringer , W. Forman

The softness parameter is based on the relative intensity of several optical emission lines emitted by the gas ionized by young massive star clusters and can be used to derive the equivalent effective temperature (T*) in those objects whose…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-05 Enrique Pérez-Montero , José M. Vílchez , Mónica Relaño , Ana Monreal-Ibero

Using a source selection biased towards high mass star forming regions, we used a Large Velocity Gradient (LVG) code to calculate the H2 densities and CS column densities for a sample of Midcourse Space Experiment (MSX) 8 micron infrared…

Astrophysics of Galaxies · Physics 2015-05-13 David Gibson , Rene Plume , Edwin Bergin , Sarah Ragan , Natalie Evans

X-rays/EUV radiation emitted from wind-embedded shocks in hot, massive stars can affect the ionization balance in their outer atmospheres, and can be the mechanism responsible for the production of highly ionized species. To allow for these…

Solar and Stellar Astrophysics · Physics 2016-05-18 Luiz P. Carneiro , J. Puls , J. O. Sundqvist , T. L. Hoffmann

We have performed three-dimensional, non-LTE radiative transfer calculations for 12CO and 13CO lines, applying them to our high-resolution hydrodynamic models of the `torus' around a SMBH in an active galactic nucleus. The hydrodynamic…

Astrophysics · Physics 2009-11-10 Keiichi Wada , Kohji Tomisaka

In this work, we report a study on the relationship between flux and intensity for molecular clouds. Our analysis is established on high-quality CO images from the Milky Way Imaging Scroll Painting (MWISP) project. The new flux-intensity…

Astrophysics of Galaxies · Physics 2024-06-13 Qing-Zeng Yan , Ji Yang , Yang Su , Yan Sun , Shaobo Zhang , Xin Zhou , Chen Wang , Yiping Ao , Xuepeng Chen , Min Wang

The X-ray emission from a simulated massive stellar cluster is investigated. The emission is calculated from a 3D hydrodynamical model which incorporates the mechanical feedback from the stellar winds of 3 O-stars embedded in a giant…

Solar and Stellar Astrophysics · Physics 2015-06-19 H. Rogers , J. M. Pittard
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