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

200 papers

We present a new large-scale survey of J=3-2 12CO emission covering 4.8 square degrees around the Rosette Nebula. Approximately 2000 compact clumps are identified, with a spatially-invariant power law mass distribution index of -1.8. Most…

A novel, to the best of our knowledge, ultralow-temperature luminescence thermometry strategy is proposed, based on a measurement of relative intensities of hyperfine components in the spectra of Ho$^{3+}$ ions doped into a crystal. A…

Optics · Physics 2025-11-25 Marina N. Popova , Mosab Diab , Boris Z. Malkin

Our ability to trace the star-forming molecular gas is important to our understanding of the Universe. We can trace this gas using CO emission, converting the observed CO intensity into the H$_2$ gas mass of the region using the CO-to-H$_2$…

Using the HEAO1 A2 full sky, 2-10 keV X-ray map evidence is found for the presence of diffuse X-ray emission in the plane of the local supercluster. Fitting this diffuse component with a simple ``pillbox'' model implies a volume X-ray…

Astrophysics · Physics 2007-05-23 Stephen P. Boughn

We present an analysis of three Chandra High Energy Transmission Gratings observations of the black hole binary Cyg X-1/HDE 226868 at different orbital phases. The stellar wind that is powering the accretion in this system is characterized…

Gravitational accretion accumulates the original mass, and this process is crucial for us to understand the initial phases of star formation. Using the specific infall profiles in optically thick and thin lines, we searched the clumps with…

Astrophysics of Galaxies · Physics 2020-09-02 Yang Yang , Zhibo Jiang , Zhiwei Chen , Shaobo Zhang , Shuling Yu , Yiping Ao

We present new or improved methods for calculating NLTE, line-blanketed model atmospheres for hot stars with winds (spectral types A to O), with particular emphasis on a fast performance. These methods have been implemented into a previous,…

Astrophysics · Physics 2009-11-10 J. Puls , M. A. Urbaneja , R. Venero , T. Repolust , U. Springmann , A. Jokuthy , M. R. Mokiem

The optical conductivity along and perpendicular to the planes is calculated assuming strong k-dependence of the scattering rate and the c-axis hopping parameter. Closed analytical expressions for the optical conductivy along these…

Superconductivity · Physics 2009-10-31 D. van der Marel

Equilibrium finite temperature observables of a CFT can be described by a local effective action for background fields -- a "thermal effective action." This effective action determines the asymptotic density of states of a CFT as a detailed…

High Energy Physics - Theory · Physics 2024-05-16 Nathan Benjamin , Jaeha Lee , Hirosi Ooguri , David Simmons-Duffin

We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high resolution parameter study with the iVINE code. The temperature is taken to be…

Solar and Stellar Astrophysics · Physics 2015-05-19 Matthias Gritschneder , Andreas Burkert , Thorsten Naab , Stefanie Walch

Infrared Dark Clouds (IRDCs) are cold, dense structures representative of the initial conditions of star formation. Many studies of IRDCs employ CO to investigate cloud dynamics. However, CO can be highly depleted from the gas phase in…

Constraining the physical and chemical evolution of molecular clouds is essential to our understanding of star formation. These investigations often necessitate knowledge of some local representative number density of the gas along the line…

Astrophysics of Galaxies · Physics 2025-04-02 Brandt A. L. Gaches , Michael Y. Grudić

\mu\ Columbae is a prototypical weak-wind O-star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS-S instrument and a low resolution spectrum with Suzaku. This allows us, for the first time, to…

Solar and Stellar Astrophysics · Physics 2015-06-11 David P. Huenemoerder , Lidia M. Oskinova , Richard Ignace , Wayne L. Waldron , Helge Todt , Kenji Hamaguchi , Shunji Kitamoto

In the subclass of high-mass X-ray binaries known as "microquasars", relativistic hadrons in the jets launched by the compact object can interact with cold protons from the star's radiatively driven wind, producing pions that then quickly…

High Energy Astrophysical Phenomena · Physics 2014-11-18 S. P. Owocki , G. E. Romero , R. H. D. Townsend , A. T. Araudo

We study how different opacity-temperature scalings affect the dynamical evolution of irradiated gas clouds using time-dependent, radiation-hydrodynamics (rad-HD) simulations. When clouds are optically thick, the bright side heats up and…

High Energy Astrophysical Phenomena · Physics 2020-02-12 Sergei Dyda , Daniel Proga , Christopher S Reynolds

For the last decade numerous researchers have been trying to develop experimental techniques to use X-ray Thomson scattering as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such…

Plasma Physics · Physics 2012-10-02 J. Nilsen , W. R. Johnson , K. T. Cheng

Deuterium fractionation in molecular ions, in particular HCO+, has been extensively used to estimate the degree of ionization in molecular clouds. This paper reviews recent work on ionization degree in homogeneous clouds. We will show that…

Astrophysics · Physics 2009-11-07 Paola Caselli

Fluorescein is perhaps the most commonly used substance to visualize tear film thickness and dynamics; better understanding of this process aids understanding of dry eye syndrome which afflicts millions of people. We study a mathematical…

Quantitative Methods · Quantitative Biology 2016-11-01 Longfei Li , R. J. Braun , W. D. Henshaw , P. E. King-Smith

Radiative transfer in a clumped winds is used to describe X-ray emission line profiles observed in the XMM-Newton RGS spectrum of the OI star Zeta Puppis. It is shown that this X-ray spectrum can be explained as originating from a…

Astrophysics · Physics 2007-05-23 L. M. Oskinova , W. -R. Hamann , A. Feldmeier

This paper investigates a case study on measuring and controlling the first-order degree of spatial coherence under different coupling adjustments in the storage ring. The experimental findings are consistent with the predicted inverse…

Accelerator Physics · Physics 2026-04-30 Y. Y. Sigari , N. A. Simonson , N. Appathurai , R. Castle , B. D. Moreno , S. Saadat , J. Wang , J. M. Vogt , M. J. Boland