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The thermal emission of dust is one of the most important tracers of the interstellar medium: multi-wavelength photometry in the far-infrared (FIR) and submillimeter (submm) can be fitted with a model, providing estimates of the dust mass.…

Astrophysics of Galaxies · Physics 2020-10-07 Lapo Fanciullo , Francisca Kemper , Peter Scicluna , Thavisha E. Dharmawardena , Sundar Srinivasan

Efforts are being made to observe the 21-cm signal from the 'cosmic dawn' using sky-averaged observations with individual radio dipoles. In this paper, we develop a model of the observations accounting for the 21-cm signal, foregrounds, and…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-26 Geraint J. A. Harker , Jonathan R. Pritchard , Jack O. Burns , Judd D. Bowman

We present radio observations of the Moon between $35$ and $80$ MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In…

Synchrotron diffuse radiation (SDR) emission is one of the major Galactic components, in the 100 MHz up to 100 GHz frequency range. Its spectrum and sky map provide valuable measure of the galactic cosmic ray electrons (GCRE) in the…

High Energy Astrophysical Phenomena · Physics 2018-11-08 Giuseppe Di Bernardo , Dario Grasso , Carmelo Evoli , Daniele Gaggero

The measurement of the $21$ cm signal from the Cosmic Dawn is a major goal for several existing and upcoming radio interferometers such as NenuFAR and the SKA. During this era before the beginning of the Epoch of Reionization, the signal is…

From the earth's crust to the human brain, remitted waves are used for sensing and imaging in a diverse range of diffusive media. Separating the source and detector increases the penetration depth of remitted light, yet rapidly decreases…

We evaluate the effect that radome transparency has on atmospheric opacity measurements performed by the skydip technique. We show that, except at rather high opacities, it is not sufficient to ignore losses in the radome (or "window")…

Astrophysics · Physics 2007-05-23 Paolo G. Calisse

We present a new method of DEEM, the direct energy encircling method, for characterising the performance of fibres in most astronomical spectroscopic applications. It's a versatile platform to measure focal ratio degradation (FRD),…

Instrumentation and Methods for Astrophysics · Physics 2019-12-25 Yunxiang Yan , Qi Yan , Gang Wang , Weimin Sun , A-Li Luo , Zhenyu Ma , Qiong Zhang , Jian Li , Shuqing Wang

We demonstrate the capability of AKARI for mapping diffuse far-infrared emission and achieved reliability of all-sky diffuse map. We have conducted an all-sky survey for more than 94 % of the whole sky during cold phase of AKARI observation…

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

A cosmic ray observatory with full-sky coverage can exploit standard anisotropy analysis methods that do not work if part of the celestial sphere is never seen. In particular, the distribution of arrival directions can be fully…

Astrophysics · Physics 2009-10-31 Paul Sommers

Radio Frequency Interference (RFI) is emitted from various sources, terrestrial or orbital, and create a nuisance for ground-based 21cm experiments. In particular, single-dish 21cm intensity mapping experiments will be highly susceptible to…

Unintended radiated emissions arise during the use of electronic devices. Identifying and mitigating the effects of these emissions is a key element of modern power engineering and associated control systems. Signal processing of the…

Computer Vision and Pattern Recognition · Computer Science 2020-09-09 Tom Grimes , Eric Church , William Pitts , Lynn Wood

Radio interferometric (RI) data are noisy under-sampled spatial Fourier components of the unknown radio sky affected by direction-dependent antenna gains. Failure to model these antenna gains accurately results in a radio sky estimate with…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 Arwa Dabbech , Audrey Repetti , Rick A. Perley , Oleg M. Smirnov , Yves Wiaux

The dispersion measure -- redshift relation of Fast Radio Bursts, $\mathrm{DM}(z)$, has been proposed as a potential new probe of the cosmos, complementary to existing techniques. In practice, however, the effectiveness of this approach…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-20 Anthony Walters , Yin-Zhe Ma , Jonathan Sievers , Amanda Weltman

Radio-frequency interference (RFI) is a major systematic limitation in radio astronomy, particularly for science cases requiring high sensitivity, such as 21 cm cosmology. Traditionally, RFI is dealt with by identifying its signature in the…

To achieve the sensitivity required to detect signals from neutral hydrogen from the Cosmic Dawn and Epoch of Reionisation it is critical to have a well-calibrated instrument which has a stable calibration over the course of the…

Instrumentation and Methods for Astrophysics · Physics 2026-03-04 Christian J. Kirkham , Dominic J. Anstey , Eloy de Lera Acedo

The cosmological principle, asserting large-scale homogeneity and isotropy, underpins the standard model of cosmology. Testing its validity using independent astronomical probes remains crucial for understanding the global structure of the…

High Energy Astrophysical Phenomena · Physics 2026-02-13 Debosi Mondal , Biswajit Pandey , Amit Mondal

X-ray emission spectroscopy is a well-established technique used to study continuum lowering in dense plasmas. It relies on accurate atomic physics models to robustly reproduce high-resolution emission spectra, and depends on our ability to…

Plasma Physics · Physics 2020-01-22 M. F. Kasim , J. S. Wark , S. M. Vinko

Optimal measurement scheme with an efficient data processing is important in quantum-enhanced interferometry. Here we prove that for a general binary outcome measurement, the simplest data processing based on inverting the average signal…

Quantum Physics · Physics 2014-07-11 X. M. Feng , G. R. Jin , W. Yang
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