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The all-sky 408 MHz map of Haslam et al. is one the most important total-power radio surveys. It has been widely used to study diffuse synchrotron radiation from our Galaxy and as a template to remove foregrounds in cosmic microwave…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. Remazeilles , C. Dickinson , A. J. Banday , M. -A. Bigot-Sazy , T. Ghosh

Reverberation chambers (RCs) were recently reported as a low-cost alternative to anechoic chambers (ACs) to perform radar cross-section (RCS) pattern measurements. The method consists of using transmitting and receiving antennas pointing…

As the era of high precision cosmology approaches, the empirically determined power spectrum of the microwave background anisotropy $C_l$ will provide a crucial test for cosmological theories. We present an exact semi-analytic framework for…

Astrophysics · Physics 2015-06-24 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

In this paper, we focus our attention on the following question: How well can we recover the power spectrum of the cosmic microwave background from the maps of a given experiment?. Each experiment is described by a a pixelization scale, a…

Astrophysics · Physics 2016-08-15 D. Sáez , J. V. Arnau

We present a technique to synthesise telluric absorption and emission features both for in-situ wavelength calibration and for their removal from astronomical spectra. While the presented technique is applicable for a wide variety of…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 A. Seifahrt , H. U. Käufl , G. Zängl , J. L. Bean , M. J. Richter , R. Siebenmorgen

CMB mapmaking relies on a data model to solve for the sky map, and this process is vulnerable to bias if the data model cannot capture the full behavior of the signal. We demonstrate that this bias is not just limited to small-scale effects…

Instrumentation and Methods for Astrophysics · Physics 2024-08-30 Sigurd Naess , Thibaut Louis

Refraction by the atmosphere causes the positions of sources to depend on the airmass through which an observation was taken. This shift is dependent on the underlying spectral energy of the source and the filter or bandpass through which…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Matthias Lee , Tamas Budavari , Ian Sullivan , Andrew Connolly

Radio surveys at frequencies of about 1 GHz allow to map the synchrotron emission in a frequency range where (except for very low Galactic latitudes or towards localized regions) it dominates over the other radio components. New all sky…

Astrophysics · Physics 2010-11-11 C. Burigana , L. La Porta , P. Reich , W. Reich

We present a new model of the diffuse Galactic synchrotron radiation, concentrating on its angular anisotropies. While previous studies have focussed on either the variation of the emissivity on large (kpc) scales, or on fluctuations due to…

Astrophysics of Galaxies · Physics 2013-06-26 Philipp Mertsch , Subir Sarkar

We present a method for suppressing contributions from higher-order terms in perturbation theory, greatly increasing the amount of information which may be extracted from the matter power spectrum. In an evolved cosmological density field…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Fergus Simpson , Alan F. Heavens , Catherine Heymans

One of the key-points for the future developments of the multiconjugate adaptive optics for the astronomy is the availability of the correction for a large fraction of the sky. The sky coverage represents one of the limits of the existing…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 Carmelo Arcidiacono , Emiliano Diolaiti , Roberto Ragazzoni , Jacopo Farinato , Elise Vernet

Purpose: This paper proposes a pipeline to acquire a scalar tapering measurement from the carina to the most distal point of an individual airway visible on CT. We show the applicability of using tapering measurements on clinically acquired…

Computer Vision and Pattern Recognition · Computer Science 2019-09-18 Kin Quan , Ryutaro Tanno , Rebecca J. Shipley , Jeremy S. Brown , Joseph Jacob , John R. Hurst , David J. Hawkes

We present a field-based signal extraction of weak lensing from noisy observations on the curved and masked sky. We test the analysis on a simulated Euclid-like survey, using a Euclid-like mask and noise level. To make optimal use of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-09 A. Loureiro , L. Whiteway , E. Sellentin , J. S. Lafaurie , A. H. Jaffe , A. F. Heavens

X-rays and gamma-rays from astronomical sources such as solar flares are mostly absorbed by the Earth's atmosphere. Resulting electron-ion production rate as a function of height depends on the intensity and wavelength of the injected…

Earth and Planetary Astrophysics · Physics 2016-04-27 Sourav Palit , Suman Ray , Sandip K. Chakrabarti

We calculate the angular power spectrum of the galactic synchrotron radiation induced by the small scale fluctuations of the magnetic field and the cosmic ray electron density. Using the observed interstellar magnetic field spectrum, which…

Astrophysics · Physics 2007-05-23 Xuelei Chen

The observed angular power spectrum of the cosmic microwave background temperature anisotropy, $C_l$, is a convolution of a cosmological radiative transport kernel with an assumed primordial power spectrum of inhomogeneities. Exquisite…

Astrophysics · Physics 2009-11-10 Arman Shafieloo , Tarun Souradeep

Foreground removal is a challenge for 21-cm tomography of the high redshift Universe. We use archival GMRT data (obtained for completely different astronomical goals) to estimate the foregrounds at a redshift ~ 1. The statistic we use is…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-12 Abhik Ghosh , Somnath Bharadwaj , Sk. Saiyad Ali , Jayaram N. Chengalur

We demonstrate how the image analysis technique of wavelet decomposition can be applied to the gamma-ray sky to separate emission on different angular scales. New structures on scales that differ from the scales of the conventional…

High Energy Astrophysical Phenomena · Physics 2016-08-03 Samuel D. McDermott , Patrick J. Fox , Ilias Cholis , Samuel K. Lee

Thomson's multitaper method estimates the power spectrum of a signal from $N$ equally spaced samples by averaging $K$ tapered periodograms. Discrete prolate spheroidal sequences (DPSS) are used as tapers since they provide excellent…

Signal Processing · Electrical Eng. & Systems 2021-03-23 Santhosh Karnik , Justin Romberg , Mark A. Davenport

Measurements with widefield radio interferometers often include the near-infinite gradient between the sky and the horizon. This causes aliasing inherent to the measurement itself, and is purely a consequence of the Fourier basis. For this…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-05 N. Barry , J. L. B. Line , C. R. Lynch , M. Kriele , J. Cook