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Related papers: Demystifying Strange O VI Line Widths with Hydrody…

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Large-scale bulk motions and hydrodynamic turbulence in the intergalactic gas inside clusters of galaxies significantly broaden X-ray emission lines. For lines of heavy ions (primarily helium-like and hydrogen-like iron ions), the…

Astrophysics · Physics 2009-11-10 N. A. Inogamov , R. A. Sunyaev

We aim to constrain the temperature and velocity structures, and H2O abundances in the winds of a sample of M-type AGB stars. We further aim to determine the effect of H2O line cooling on the energy balance in the inner circumstellar…

Solar and Stellar Astrophysics · Physics 2016-06-15 M. Maercker , T. Danilovich , H. Olofsson , E. De Beck , K. Justtanont , R. Lombaert , P. Royer

We present synthetic observations of star-forming interstellar medium structures obtained by hydrodynamic calculations of a turbulent box under the influence of an ionising radiation field. The morphological appearance of the pillar-like…

Astrophysics of Galaxies · Physics 2015-05-30 Barbara Ercolano , James E. Dale , Matthias Gritschneder , Mark Westmoquette

We analyse the distribution and origin of OVI in the Circumgalactic Medium (CGM) of dark-matter haloes of $\sim 10^{12}$ M$_\odot$ at $z\sim1$ in the VELA cosmological zoom-in simulations. We find that the OVI in the inflowing cold streams…

Far-ultraviolet spectra of 11 AGNs observed by FUSE are analyzed to obtain measures of O VI 1031.93 A absorption occurring over very long paths through Milky Way halo gas. Strong O VI absorption is detected along 10 of 11 sight lines.…

Hydrogen recombination lines provide key diagnostics of ionized gas in galaxies, yet most hydrodynamical simulations estimate hydrogen level populations using interpolated emissivity tables rather than computing them directly from local…

Astrophysics of Galaxies · Physics 2026-04-08 Yuankang Liu , Tom Theuns , Tsang Keung Chan , Alexander J. Richings , Anna F. McLeod

We report the discovery of an O VI absorption system at z(abs) = 0.14232 in a high resolution FUV spectrum of PG0953+415 obtained with the Space Telescope Imaging Spectrograph (STIS). Both lines of the O VI 1032, 1038 doublet and…

Astrophysics · Physics 2009-10-31 Todd M. Tripp , Blair D. Savage

Column densities for H I, Al III, Si IV, C IV, and O VI toward 109 stars and 30 extragalactic objects have been assembled to study the extensions of these species away from the Galactic plane into the Galactic halo. H I and Al III mostly…

Astrophysics of Galaxies · Physics 2015-05-13 Blair D. Savage , Bart Wakker

We present two sets of grid-based hydrodynamical simulations of high-velocity clouds (HVCs) traveling through the diffuse, hot Galactic halo. These HI clouds have been suggested to provide fuel for ongoing star formation in the Galactic…

Astrophysics of Galaxies · Physics 2011-02-11 Fabian Heitsch , Mary E. Putman

Transits in the H I 1216 A (Lyman alpha), O I 1334 A, C II 1335 A, and Si III 1206.5 A lines constrain the properties of the upper atmosphere of HD209458b. In addition to probing the temperature and density profiles in the thermosphere,…

Earth and Planetary Astrophysics · Physics 2015-06-11 T. T. Koskinen , R. V. Yelle , M. J. Harris , P. Lavvas

The atmospheres of massive O-type stars (O stars) are dynamic, turbulent environments resulting from radiatively driven instabilities over the iron bump, located slightly beneath the stellar surface. Here, complex radiation hydrodynamic…

We use the three-dimensional hydrodynamic code of Stein and Nordlund to realistically simulate the upper layers of the solar convection zone in order to study physical characteristics of solar oscillations. Our first result is that the…

Astrophysics · Physics 2009-10-31 D. Georgobiani , A. G. Kosovichev , R. Nigam , A. Nordlund , R. F. Stein

We present a theoretical study of intergalactic metal absorption lines imprinted in the spectra of distant quasars during and after the Epoch of Reionization (EoR). We use high resolution hydrodynamical simulations at high redshift ($4…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-06 L. A. Garcia , E. Tescari , E. V. Ryan-Weber , J. S. B. Wyithe

We present an analysis combining the simultaneous measurement of intergalactic absorption by hydrogen (H I), helium (He II) and oxygen (O VI) in UV and optical quasar spectra. The combination of the H I and He II Lyman-alpha forests through…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-04 Sean Morrison , Matthew M. Pieri , David Syphers , Tae-Sun Kim

Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical…

Solar and Stellar Astrophysics · Physics 2018-03-14 A. Chiavassa , L. Casagrande , R. Collet , Z. Magic , L. Bigot , F. Thevenin , M. Asplund

We conduct a detailed comparison of broad-band spectral energy distributions of six z >= 5.5 galaxies against galaxies drawn from cosmological hydrodynamic simulations. We employ a new tool called SPOC, which constrains the physical…

Astrophysics · Physics 2008-11-26 K. Finlator , R. Dave' , B. Oppenheimer

We study the circumgalactic medium (CGM) of a z=0.54 simulated dwarf galaxy using hydroART simulations. We present our analysis methods, which emulate observations, including objective absorption line detection, apparent optical depth (AOD)…

Neutral hydrogen 21 cm transition is a useful tracer of the neutral interstellar medium. However, inferring physical condition from the observed 21 cm absorption and/or emission spectra is often not straightforward. One complication in…

Astrophysics of Galaxies · Physics 2021-01-13 Atanu Koley , Nirupam Roy

The spatial structure of the emission lines and continuum over the 50 arcsecond extent of the nearby, O-rich, planetary nebula NGC 7009 (Saturn Nebula) have been observed with the MUSE integral field spectrograph on the ESO Very Large…

We investigate the role of non-thermal electrons in the formation regions of Halpha, Hbeta, and Hgamma lines in order to unfold their influence on the formation of these lines. We concentrate on pulse-beam heating varying on a subsecond…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. Kasparova , M. Varady , P. Heinzel , M. Karlicky , Z. Moravec