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We study the statistics of the Lyman-$\alpha$ forest in a flat LCDM cosmology with the N-body + Eulerian hydrodynamics code Nyx. We produce a suite of simulations, covering the observationally relevant redshift range $2 \leq z \leq 4$. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-24 Zarija Lukić , Casey Stark , Peter Nugent , Martin White , Avery Meiksin , Ann Almgren

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…

In this work, we present a planar laser-induced fluorescence (PLIF) system for two-dimensional (2D) spatial and phase-resolved ion velocity distribution function (IVDF) measurements. A continuous-wave tunable diode laser produces a laser…

Plasma Physics · Physics 2025-04-04 Sung Hyun Son , Ivan Romadanov , Nirbhav Singh Chopra , Yevgeny Raitses

Context: Brown dwarfs exhibit complex atmospheric signatures, and their properties depend sensitively on effective temperature, surface gravity, and metallicity. Several physical properties of brown dwarfs in binary systems can be well…

Astrophysics · Physics 2009-11-13 K. Geißler , G. Chauvin , M. F. Sterzik

We provide a large image parameter dataset extracted from the Solar Dynamics Observatory (SDO) mission's AIA instrument, for the period of January 2011 through the current date, with the cadence of six minutes, for nine wavelength channels.…

Solar and Stellar Astrophysics · Physics 2019-07-31 Azim Ahmadzadeh , Dustin J. Kempton , Rafal A. Angryk

We examine the statistics of the low-redshift Ly-alpha forest in an adaptive mesh refinement hydrodynamic cosmological simulation of sufficient volume to include distinct large-scale environments. We compare our HI column density…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Stephanie Tonnesen , Britton D. Smith , Juna Kollmeier , Renyue Cen

We study the process of cosmic reionization and estimate the ionizing background in the IGM using the Lyman series absorption in the spectra of the four quasars at 5.7<z<6.3 discovered by the SDSS. We derive the evolution of the ionizing…

CHROMIS, a new imaging spectrometer at the Swedish 1-m Solar Telescope (SST), can observe the chromosphere in the H and K lines of Ca II at high spatial and spectral resolution. Accurate modeling as well as an understanding of the formation…

To overcome the challenges associated with poor temporal stability of perovskite solar cells, methods are required that allow for fast iteration of fabrication and characterisation, such that optimal device performance and stability may be…

Recent suggestions of a "photon underproduction crisis" (Kollmeier \etal\ 2014) have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (UVB). The balance of hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-23 J. Michael Shull , Joshua Moloney , Charles W. Danforth , Evan M. Tilton

We have developed a modular semi-numerical code that computes the time and spatially dependent ionization of neutral hydrogen (HI), neutral (HeI) and singly ionized helium (HeII) in the intergalactic medium (IGM). The model accounts for…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-02 Anne Hutter

We present a survey of O VI line widths obtained from hydrodynamic simulations that model the mixing between High Velocity Clouds and the circumgalactic medium and track the non-equilibrium ionization populations of the ions. We run 10…

Astrophysics of Galaxies · Physics 2025-09-16 Chen Wang , Eric Goetz , Robin Shelton

The ionizing photon production efficiency, $\xi_{ion}$, is a critical parameter that provides a number of physical constraints to the nature of the early Universe, including the contribution of galaxies to the timely completion of the…

We gather infrared (IR) photometric data from 8 to 500 microns (Spitzer, WISE, IRAS and Herschel) for all of the HRS galaxies. Draine & Li (2007) models are fit to the data from which the stellar contribution has been carefully removed. We…

We compare three methods to measure the count-in-cell probability density function of galaxies in a spectroscopic redshift survey. From this comparison we found that when the sampling is low (the average number of object per cell is around…

Despite being one of the weakest dimers in nature, low-spectral-resolution Voyager/IRIS observations revealed the presence of (H$_2$)$_2$ dimers on Jupiter and Saturn in the 1980s. However, the collision-induced H$_2$-H$_2$ opacity…

Earth and Planetary Astrophysics · Physics 2018-03-28 L. N. Fletcher , M. Gustafsson , G. S. Orton

We use optical integral field spectroscopy and 8 and 24 micron mid-IR observations of the giant HII region NGC 588 in the disc of M33 as input and constraints for two-dimensional tailor-made photoionisation models. Two different geometrical…

We calculate theoretical population ratios of the ground fine-structure levels of some atoms/ions which typically exhibit UV lines in the spectra of QSO absorbers redward the Ly-alpha forest: C0, C+, O0, Si+ and Fe+. The most reliable…

Astrophysics · Physics 2009-10-31 A. I. Silva , S. M. Viegas

We present a new training set for estimating empirical photometric redshifts of galaxies, which was created as part of the 2dFLenS project. This training set is located in a 700 sq deg area of the KiDS South field and is randomly selected…

Infrared Imaging Video Bolometer (IRVB) measures total radiation power loss from plasma in 2 dimensions through a pinhole camera geometry. Where a free-standing thin metal foil act as a broad band absorber from Soft X-Rays to IR radiation.…

Plasma Physics · Physics 2026-05-19 Vinit Pandya , Santosh P. Pandya , Ansh Patel , Kumudni Tahiliani , Kumar Ajay
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