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Related papers: Molecular Hydrogen Optical Depth Templates for FUS…

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We provide new post-COSTAR data on one sightline (Mrk 421) and updated data from another (I Zw 1) from our Hubble Space Telescope (HST) survey of intergalactic Lyman-alpha clouds located along sightlines to four bright quasars passing…

Astrophysics · Physics 2007-05-23 J. Michael Shull , John T. Stocke , Steve Penton

We measure the effect of high column density absorbing systems of neutral hydrogen (HI) on the one-dimensional (1D) Lyman-alpha forest flux power spectrum using cosmological hydrodynamical simulations from the Illustris project. High column…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-10 Keir K. Rogers , Simeon Bird , Hiranya V. Peiris , Andrew Pontzen , Andreu Font-Ribera , Boris Leistedt

A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…

Astrophysics · Physics 2007-05-23 Tommy Wiklind , Francoise Combes

Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous…

At visible wavelengths, Venus appears serene and pale-yellow, but since the 1920s, observers have noted high-contrast features in the ultraviolet. These features track the about 4-day superrotation of the upper cloud deck and vary widely…

Earth and Planetary Astrophysics · Physics 2026-01-14 Jan Spacek , Yeon J. Lee , Paul B. Rimmer , Janusz J. Petkowski

We report the detection of OH+ and H2O+ in the z=0.89 absorber toward the lensed quasar PKS1830-211. The abundance ratio of OH+ and H2O+ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic…

We report a lambda > 1cm search for rotational molecular absorption towards quasars, now possible with the upgraded Australia Telescope Compact Array (ATCA). The targets were PKS 0201+113, PKS 0336-017 and Q 0537-286, where known damped…

Astrophysics · Physics 2009-11-07 S. J. Curran , M. T. Murphy , J. K. Webb , Y. M. Pihlstroem

We have performed high-resolution hydrodynamic simulations of the Lyman-alpha forest in a variety of popular cold dark matter dominated cosmologies, including a low density and a vacuum-dominated model. The fluctuation amplitude of these…

Astrophysics · Physics 2009-10-31 Tom Theuns , Anthony Leonard , Joop Schaye , George Efstathiou

We derive total (atomic + molecular) hydrogen densities in giant molecular clouds (GMCs) in the nearby spiral galaxy M33 using a method that views the atomic hydrogen near regions of recent star formation as the product of…

Astrophysics of Galaxies · Physics 2015-05-27 J. S. Heiner , R. J. Allen , P. C. van der Kruit

We present a first-principles-based multiscale simulation framework for quantitative predictions of the high-energy part of the Ultraviolet Photoelectron Spectroscopy (UPS) spectra of amorphous molecular solids. The approach combines a…

We show in this paper why molecular millimeter absorption line searches in DLAs have been unsuccessful. We use CO emission line maps of local galaxies to derive the H2 column density distribution function f(N_H2) at z=0. We show that it…

Astrophysics · Physics 2009-11-11 M. A. Zwaan , J. X. Prochaska

We present the discovery of molecular hydrogen (H_2), including the presence of vibrationally-excited H_2^* in the optical spectrum of the afterglow of GRB 120815A at z=2.36 obtained with X-shooter at the VLT. Simultaneous photometric…

We present a new measurement of the deuterium-to-hydrogen ratio (D/H) in the Lyman limit absorption system at $z = 3.572$ towards Q1937--1009. We use an improved method to measure D/H in QSO absorption systems, which includes extra…

Astrophysics · Physics 2009-10-30 Scott Burles , David Tytler

One of the readily accessible observables in trapped cold-atom experiments is the column density, which is determined from optical depth (OD) obtained from absorption imaging and the absorption cross-section ($\sigma_{\rm abs}$). Here we…

Recent experimental results about the formation of molecular hydrogen on astrophysically relevant surfaces under conditions close to those encountered in the interstellar medium are analyzed using rate equations. The parameters of the rate…

Astrophysics · Physics 2009-10-31 N. Katz , I. Furman , O. Biham , V. Pirronello , G. Vidali

A mathematical model is developed to describe column adsorption when the contaminant constitutes a significant amount of the fluid. This requires modelling the variation of pressure and velocity, in addition to the usual…

Fluid Dynamics · Physics 2025-02-10 Timothy G. Myers , Marc Calvo-Schwarzwalder , Francesc Font , Abel Valverde

Context. Neutral atomic hydrogen (HI) absorption lines can be used to probe the cold neutral medium (CNM) at high Galactic latitudes. Cold HI with a significant optical depth from the GASKAP-HI survey is found to be located predominantly if…

Astrophysics of Galaxies · Physics 2025-11-26 P. M. W. Kalberla

We present new theoretical calculations of the line profile of Lyman gamma that include transitions in which a photon is absorbed by a neutral hydrogen atom while it interacts with a proton. Models show that two absorption features located…

Astrophysics · Physics 2011-05-23 G. Hébrard , N. F. Allard , J. F. Kielkopf , P. Chayer , J. Dupuis , J. W. Kruk , I. Hubeny

A small survey of the UV-absorbing gas in 12 low-$z$ galaxy groups has been conducted using the Cosmic Origins Spectrograph (COS) on-board the Hubble Space Telescope (HST). Targets were selected from a large, homogeneously-selected sample…

Molecular hydrogen absorption in the damped Lyman-alpha system at z = 2.34 towards quasar Q1232+082 is analyzed in order to derive a constraint on a possible temporal variation of the proton-to-electron mass ratio, mu, over cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-11 M. Daprà , M. van der Laan , M. T. Murphy , W. Ubachs