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We use an information-theoretic measure of shape complexity known as configurational entropy (CE) to investigate numerically the remarkably long lifetimes of spherically-symmetric ``resonant oscillons'' in three-dimensional and of…

High Energy Physics - Theory · Physics 2020-05-20 Marcelo Gleiser , Max Krackow

We test the consistency of several independent astrophysical measurements of fundamental dimensionless constants. In particular, we compare direct measurements of the fine-structure constant $\alpha$ and the proton-to-electron mass ratio…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-05 M. C. Ferreira , O. Frigola , C. J. A. P. Martins , A. M. R. V. L. Monteiro , J. Solà

Context. OB stars are important building blocks of the Universe, but we have only a limited sample of them well understood enough from an asteroseismological point of view to provide feedback on the current evolutionary models. Our study…

For light curves sampled on an uneven grid of observation times, the shape of the power density spectrum (PDS) includes severe distortion effects due to the window function, and simulations of light curves are indispensable to recover the…

Astrophysics · Physics 2009-11-10 Martin Mueller , Greg Madejski , Chris Done , Piotr Zycki

We explore the multi-faceted important features of turbulence (e.g., anisotropy, dispersion, diffusion) in the three-dimensional (3D) wavenumber domain ($k_\parallel$, $k_{\perp,1}$, $k_{\perp,2}$), by employing the k-filtering technique to…

Plasma Physics · Physics 2022-11-30 Rong Lin , Jiansen He , Xingyu Zhu , Lei Zhang , Die Duan , Fouad Sahraoui , Daniel Verscharen

Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was…

Unified recombination cross sections and rates are computed for (e + Fe XVIII) --> Fe XVII including non-resonant and resonant (radiative and di-electronic recombination, RR and DR) processes in an ab initio manner with relativistic fine…

Astrophysics · Physics 2009-10-31 Anil K. Pradhan , Sultana N. Nahar , Hong Lin Zhang

When it comes to searches for extensions to general relativity, large efforts are being dedicated to accurate predictions for the power spectrum of density perturbations. While this observable is known to be sensitive to the gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-08 Claudio Llinares , Nuala McCullagh

We present measurements of the weak gravitational lensing shear power spectrum based on $450$ sq. deg. of imaging data from the Kilo Degree Survey. We employ a quadratic estimator in two and three redshift bins and extract band powers of…

Stellar limb-darkening impacts a wide range of astronomical measurements. The accuracy to which it is modelled limits the accuracy in any covariant parameters of interest, such as the radius of a transiting planet. With the ever growing…

Solar and Stellar Astrophysics · Physics 2015-12-16 David M. Kipping

Gravitational flexion, caused by derivatives of the gravitational tidal field, is potentially important for the analysis of the dark-matter distribution in gravitational lenses, such as galaxy clusters or the dark-matter haloes of galaxies.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Massimo Viola , Peter Melchior , Matthias Bartelmann

The nature of dark energy and the complete theory of gravity are two central questions currently facing cosmology. A vital tool for addressing them is the 3-point correlation function (3PCF), which probes deviations from a spatially random…

Elemental abundances can be determined from stellar spectra, making it possible to study galactic formation and evolution. Accurate atomic data is essential for the reliable interpretation and modeling of astrophysical spectra. In this…

Solar and Stellar Astrophysics · Physics 2023-09-13 Madeleine Burheim , Henrik Hartman , Hampus Nilsson

Kinetic jet power estimates based exclusively on observed monochromatic radio luminosities are highly uncertain due to confounding variables and a lack of knowledge about some aspects of the physics of active galactic nuclei (AGNs). We…

Astrophysics of Galaxies · Physics 2017-12-27 Ross J. Turner , Stanislav S. Shabala , Martin G. H. Krause

Core-level spectra of 1s electrons of elements heavier than Ne show significant relativistic effects. We combine advances in orbital optimized DFT (OO-DFT) with the spin-free exact two-component (X2C) model for scalar relativistic effects,…

Chemical Physics · Physics 2022-04-19 Leonardo A. Cunha , Diptarka Hait , Richard Kang , Yuezhi Mao , Martin Head-Gordon

Leveraging the large sample size of low-resolution spectroscopic surveys to constrain white dwarf stellar structure requires an accurate understanding of the shapes of hydrogen absorption lines, which are pressure broadened by the Stark…

Recent measurements of gamma rays from the powerful quasar 3C273 by the Compton Gamma Ray Observatory show that a powerful cosmic accelerator must be operating. In this paper the evidence for proton acceleration is collected with the result…

Astrophysics · Physics 2009-10-22 Karl Mannheim

In this letter we report a Chandra X-ray detection of the double northern hot spot of the radio quasar 3C 351. The hot spot has also been observed in the optical with the Hubble Space Telescope (R-band) and with the 3.5m. Telescopio…

Astrophysics · Physics 2009-11-07 G. Brunetti , M. Bondi , A. Comastri , M. Pedani , S. Varano , G. Setti , M. J. Hardcastle

We present a measure of the power spectrum on scales from 15 to 800 Mpc/h using the ROSAT-ESO Flux-Limited X-Ray(REFLEX) galaxy cluster catalogue. The REFLEX survey provides a sample of the 452 X-ray brightest southern clusters of galaxies…

The aim of the Swedish-Japanese EISCAT campaign in February 1999 was to measure the ionospheric parameters inside and outside the auroral arcs. The ion line radar experiment was optimised to probe the E-region and lower F-region with as…

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