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Unveiling the thermal history of the intergalactic medium (IGM) at $4 \leq z \leq 5$ holds the potential to reveal early onset HeII reionization or lingering thermal fluctuations from HI reionization. We set out to reconstruct the IGM gas…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-10 Fahad Nasir , Prakash Gaikwad , Frederick B. Davies , James S. Bolton , Ewald Puchwein , Sarah E. I. Bosman

Numerical simulations indicate that the smooth, photoionized intergalactic medium (IGM) responsible for the low column density Lyman-alpha forest follows a well defined temperature-density relation. We show that such an equation of state…

Astrophysics · Physics 2007-05-23 Joop Schaye , Tom Theuns , Anthony Leonard , George Efstathiou

In weakly magnetized, dilute plasmas in which thermal conduction along magnetic field lines is important, the usual convective stability criterion is modified. Instead of depending on entropy gradients, instability occurs for small…

Astrophysics · Physics 2009-11-13 Ian J. Parrish , James M. Stone

Linear analysis of the stability of diffuse clouds in the cold neutral medium with uniform magnetic field is performed. We consider that gas in equilibrium state is heated by cosmic rays, X-rays and electronic photoeffect on the surface of…

Solar and Stellar Astrophysics · Physics 2019-05-22 Alexander E. Dudorov , Constantine E. Stepanov , Sergey O. Fomin , Sergey A. Khaibrakhmanov

Thermal instability (TI) plays a crucial role in the formation of multiphase structures and their dynamics in the Interstellar Medium (ISM) and is a leading theory for cold cloud creation in various astrophysical environments. In this paper…

Astrophysics of Galaxies · Physics 2021-08-24 R. Michael Jennings , Yuan Li

A finite-element method dependant adjoint-based procedure to determine the temperature field of structures based on measured displacements or strains and a set of standard loads is developed and tested. Given a series of force and…

We propose an adaptive mesh refinement strategy for immersed isogeometric analysis, with application to steady heat conduction and viscous flow problems. The proposed strategy is based on residual-based error estimation, which has been…

The thermal state of the intergalactic medium (IGM) at z < 6 constrains the nature and timing of cosmic reionization events, but its inference from the Ly-alpha forest is degenerate with the 3-D structure of the IGM on ~100 kpc scales,…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-14 Girish Kulkarni , Joseph F. Hennawi , Jose Oñorbe , Alberto Rorai , Volker Springel

The temperature of the diffuse, photo-heated intergalactic medium (IGM) depends on its reionization history because the thermal time scales are long. The widths of the hydrogen Lyman-alpha absorption lines seen in the spectra of distant…

In many magnetized, dilute astrophysical plasmas, thermal conduction occurs almost exclusively parallel to magnetic field lines. In this case, the usual stability criterion for convective stability, the Schwarzschild criterion, which…

Astrophysics · Physics 2008-11-26 Ian J. Parrish , James M. Stone

Observations have suggested substantial departures from pressure equilibrium in the interstellar medium (ISM) in the plane of the Galaxy, even on scales under 50 pc. Nevertheless, multi-phase models of the ISM assume at least locally…

Astrophysics · Physics 2007-05-23 Mordecai-Mark Mac Low , Dinshaw Balsara , Miguel A. Avillez , Jongsoo Kim

Galactic dynamo models have generally relied on input parameters that are very challenging to constrain. We address this problem by developing a model that uses observable quantities as input: the galaxy rotation curve, the surface…

Astrophysics of Galaxies · Physics 2024-04-04 Luke Chamandy , Rion Glenn Nazareth , Gayathri Santhosh

An adaptive mesh refinement and error estimation method for numerically solving optimal control problems is developed using Legendre-Gauss-Radau direct collocation. In regions of the solution where the desired accuracy tolerance has not…

Optimization and Control · Mathematics 2024-10-11 George V. Haman , Anil V. Rao

Substructure in the interstellar medium (ISM) is crucial for establishing the correlation between star formation and feedback and has the capacity to significantly perturb stellar orbits, thus playing a central role in galaxy dynamics and…

Astrophysics of Galaxies · Physics 2026-02-06 Shaunak Modak , Eve C. Ostriker , Chris Hamilton , Scott Tremaine

Far-infrared (FIR) and mid-infrared (MIR) fine-structure lines (FSLs) provide key diagnostics of physical conditions in the interstellar medium (ISM). Building on empirical relations established in our previous work, we use photoionization…

Astrophysics of Galaxies · Physics 2025-07-17 Bo Peng , Amit Vishwas , Cody Lamarche , Gordon Stacey , Catie Ball , Christopher Rooney , Thomas Nikola , Carl Ferkinhoff

A two-dimensional Ising model with short-range interactions and mobile defects describing the formation and thermal destruction of defect stripes is studied. In particular, the effect of a local pinning of the defects at the sites of…

Condensed Matter · Physics 2007-05-23 M. Holtschneider , W. Selke

Phase-field models of fracture introduce smeared cracks of width commensurate with a regularisation length parameter $\epsilon$ and obeying a minimum energy principle. Mesh adaptivity naturally suggests itself as a means of supplying…

Computational Engineering, Finance, and Science · Computer Science 2022-06-01 Dhananjay Phansalkar , Kerstin Weinberg , Michael Ortiz , Sigrid Leyendecker

We present new measurements of the thermal state of the intergalactic medium (IGM) at $z\sim2.4$ derived from absorption line profiles in the Ly$\alpha$ forest. We use a large set of high-resolution hydrodynamical simulations to calibrate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 James S. Bolton , George D. Becker , Martin G. Haehnelt , Matteo Viel

Line intensity mapping (LIM) is a promising approach to study star formation and the interstellar medium (ISM) in galaxies by measuring the aggregate line emission from the entire galaxy population. In this work, we develop a simple yet…

Astrophysics of Galaxies · Physics 2020-01-08 Guochao Sun , Brandon S. Hensley , Tzu-Ching Chang , Olivier Doré , Paolo Serra

Context: The thermal instability is one of the dynamical agents for turbulence in the diffuse interstellar medium, where both, turbulence and thermal instability interact in a highly non-linear manner. Aims: We study basic properties of…

Astrophysics of Galaxies · Physics 2015-05-19 D. Seifried , W. Schmidt , J. C. Niemeyer