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Current results from the Lyman alpha forest assume that the primordial power spectrum of density perturbations follows a simple power law form, with running. We present the first analysis of Lyman alpha data to study the effect of relaxing…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-16 Simeon Bird , Hiranya V. Peiris , Matteo Viel , Licia Verde

Real-time estimation of ocean wave heights using high-frequency (HF) radar has attracted great attention. This method offers the benefit of easy maintenance by virtue of its ground-based installation. However, it is adversely affected by…

Numerical Analysis · Mathematics 2025-05-20 Kaede Watanabe , Toshiaki Yachimura , Tsubasa Terada , Hiroshi Kameda , Ryuhei Takahashi , Hiroshi Suito

When modelling the ionisation of gas in the intergalactic medium after reionisation, it is standard practice to assume a uniform radiation background. This assumption is not always appropriate; models with radiative transfer show that…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-02 Teresita Suarez , Andrew Pontzen

Spectral energy distributions for models of arbitrarily rotating stars are computed using two dimensional rotating stellar models, NLTE plane parallel model atmospheres, and a code to integrate the appropriately weighted intensities over…

Astrophysics · Physics 2008-05-09 A. Gillich , R. Deupree , C. Lovekin , I. Short , N. Toque

We estimate the lensing convergence power spectrum from supernovae magnification data using real space correlation function technique. For our analysis we have utilized 296 supernovae from 5-year Supernovae Legacy Survey in the weak lensing…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-07 Ayan Mitra , Barun Kumar Pal , Supratik Pal

The observational data of the near infrared bands (H and K) have been used for the modeling mean light curves. Also the visual observational data have been fitted the same. The infrared and visual mean light curves were compared. All…

Solar and Stellar Astrophysics · Physics 2016-07-14 L. S. Kudashkina

A method is proposed for deriving the dispersion measure (related to the line-of-sight integrated free electron density) to high-redshift, powerful synchrotron radio sources by analysis of the temporal/spectral properties of the recorded…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 R. V. E. Lovelace , D. W. Richards

An important application of next-generation wide-field radio interferometers is making high dynamic range maps of radio emission. Traditional deconvolution methods like CLEAN can give poor recovery of diffuse structure, prompting the…

Instrumentation and Methods for Astrophysics · Physics 2024-10-23 Katrine A. Glasscock , Philip Bull , Jacob Burba , Hugh Garsden , Michael J. Wilensky

We introduce a method for analyzing radio interferometry data which produces maps which are optimal in the Bayesian sense of maximum posterior probability density, given certain prior assumptions. It is similar to maximum entropy…

Astrophysics · Physics 2009-11-11 Edmund C. Sutton , Benjamin D. Wandelt

In a recent paper we have calculated the power density spectrum of Gamma-Ray Bursts arising from multiple shocks in a relativistic wind. The wind optical thickness is one of the factors to which the power spectrum is most sensitive,…

Astrophysics · Physics 2009-10-31 M. Spada , A. Panaitescu , P. Meszaros

Light spectra are a very important source of information for diverse classification problems, e.g., for discrimination of materials. To lower the cost for acquiring this information, multispectral cameras are used. Several techniques exist…

Image and Video Processing · Electrical Eng. & Systems 2022-09-19 Frank Sippel , Jürgen Seiler , Nils Genser , André Kaup

Radio astronomy has changed. For years it studied relatively rare sources, which emit mostly non-thermal radiation across the entire electromagnetic spectrum, i.e. radio quasars and radio galaxies. Now it is reaching such faint flux…

Astrophysics of Galaxies · Physics 2016-10-19 Paolo Padovani

I present the results of a new approach to the intensity and photon density spectrum of the intergalactic background light as a function of redshift using observational data obtained in many different wavelength bands from local to deep…

High Energy Astrophysical Phenomena · Physics 2013-02-11 Floyd W. Stecker

We study the impact of the spread spectrum effect in radio interferometry on the quality of image reconstruction. This spread spectrum effect will be induced by the wide field-of-view of forthcoming radio interferometric telescopes. The…

Instrumentation and Methods for Astrophysics · Physics 2013-01-31 Laura Wolz , Filipe B. Abdalla , Rafael E. Carrillo , Yves Wiaux , Jason D. McEwen

We show that mid-infrared data from the all-sky WISE survey can be used as a robust photometric redshift indicator for powerful radio AGN, in the absence of other spectroscopic or multi-band photometric information. Our work is motivated by…

Instrumentation and Methods for Astrophysics · Physics 2017-09-27 M. Glowacki , J. R. Allison , E. M. Sadler , V. A. Moss , T. H. Jarrett

Context. Arrays of radio antennas have proven to be successful in astroparticle physics with the observation of extensive air showers initiated by high-energy cosmic rays in the Earth's atmosphere. Accurate determination of the energy scale…

Instrumentation and Methods for Astrophysics · Physics 2023-11-08 M. Büsken , T. Fodran , T. Huege

We present the improved visibility based Tapered Gridded Estimator (TGE) for the power spectrum of the diffuse sky signal. The visibilities are gridded to reduce the computation, and tapered through a convolution to suppress the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-25 Samir Choudhuri , Somnath Bharadwaj , Suman Chatterjee , Sk. Saiyad Ali , Nirupam Roy , Abhik Ghosh

An updated model for the synchrotron and inverse Compton emission from a population of high energy electrons of the Crab Nebula is used to reproduce the measured spectral energy distribution from radio to high energy gamma-rays. By…

Instrumentation and Methods for Astrophysics · Physics 2010-08-27 M. Meyer , D. Horns , H. -S. Zechlin

Incorporating wide-field considerations in interferometric imaging is of increasing importance for next-generation radio telescopes. Compressed sensing techniques for interferometric imaging have been extended to wide fields recently,…

Instrumentation and Methods for Astrophysics · Physics 2011-08-29 J. D. McEwen , Y. Wiaux

We carried out numerical experiments on the evaluation of the possibilities of obtaining the information about brightness distributions for the components of eclipsing variables from the data of high-precision photometry expected for…

Astrophysics · Physics 2009-11-11 M. B. Bogdanov , A. M. Cherepashchuk