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The mass-loss rates from single massive stars are high enough to form radio photospheres at large distances from the stellar surface where the wind is optically thick to (thermal) free-free opacity. Here we calculate the far-infrared,…

Solar and Stellar Astrophysics · Physics 2022-06-15 Christiana Erba , Richard Ignace

A comparison between the line of sight power spectrum of absorption in the Lyman-alpha forest and the cross power spectrum between the absorption in neighboring lines of sight offers an evolution-free means to constrain the cosmological…

Astrophysics · Physics 2007-05-23 Adam Lidz , Lam Hui , Arlin P. S. Crotts , Matias Zaldarriaga

In 2018 the EDGES experiment claimed the first detection of the global cosmic 21cm signal, which featured an absorption trough centered around $z \sim 17$ with a depth of approximately -500mK. This amplitude is deeper than the standard…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-11 Junsong Cang , Andrei Mesinger , Steven G. Murray , Daniela Breitman , Yuxiang Qin , Roberto Trotta

If dark matter decays or annihilates into electrons and positrons, it can affect radiation and cosmic-ray backgrounds. We review a novel, more general analysis of constraints on decaying dark matter models, by introducing the response…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-13 Le Zhang

We use high angular resolution data, measured from visibility of sources at the longest baseline of 4500 m of the Australia Telescope Compact Array (ATCA), for the Australia Telescope 20 GHz (AT20G) survey to obtain angular size information…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. Chhetri , R. D. Ekers , E. K. Mahony , P. A. Jones , M. Massardi , R. Ricci , E. M. Sadler

The spectrum of gyrosynchrotron emission from solar flares generally peaks in the microwave range. Its optically-thin, high-frequency component, above the spectral peak, is often used for diagnostics of the nonthermal electrons and the…

Solar and Stellar Astrophysics · Physics 2018-11-07 Gregory D. Fleishman , Maria A. Loukitcheva , Varvara Yu. Kopnina , Gelu M. Nita , Dale E. Gary

According to a generally accepted paradigm, small intrinsic sizes of Compact Steep Spectrum (CSS) radio sources are a direct consequence of their youth, but in later stages of their evolution they are believed to become large-scale sources.…

Astrophysics · Physics 2009-11-13 Andrzej Marecki , Magdalena Kunert-Bajraszewska , Ralph E. Spencer

LS 5039 is an X-ray binary that presents non-thermal radio emission. The radiation at $\sim 5$ GHz is quite steady and optically thin, consisting on a dominant core plus an extended jet-like structure. There is a spectral turnover around 1…

Astrophysics · Physics 2009-11-13 V. Bosch-Ramon

The recent HEGRA observations of the blazar Mkn 501 show strong curvature in the very high energy gamma-ray spectrum. Applying the gamma-ray opacity derived from an empirically based model of the intergalactic infrared background radiation…

Curved broad-band spectral distributions of non-thermal sources like blazars are described well by a log-parabolic (LP) law where the second degree term measures the curvature. LP energy spectra can be obtained for relativistic electrons by…

Astrophysics · Physics 2009-11-11 E. Massaro , A. Tramacere , M. Perri , P. Giommi , G. Tosti

The propagation of a surface acoustic wave (SAW) on GaAs/AlGaAs heterostructures is studied in the case where the two-dimensional electron gas (2DEG) is subject to a strong magnetic field and a smooth random potential with correlation…

Mesoscale and Nanoscale Physics · Physics 2009-10-28 Andreas Knaebchen , Yehoshua Levinson , Ora Entin-Wohlman

This paper presents a new grid-based method for investigating the evolution of the steep-spectrum radio luminosity function, with the aim of quantifying the high-redshift cut-off suggested by previous work. To achieve this, the Combined…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 E. E. Rigby , P. N. Best , M. H. Brookes , J. A. Peacock , J. S. Dunlop , H. J. A. Röttgering , J. V. Wall , L. Ker

We reflect on the prospect of exploiting the recoil associated with absorption and emission of photons to perform spectroscopy of a single molecular ion. For this recoil to be detectable, the molecular ion is sympathetically cooled by a…

We study the impact of sky-based calibration errors from source mismodeling on 21\,cm power spectrum measurements with an interferometer and propose a method for suppressing their effects. While emission from faint sources that are not…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Aaron Ewall-Wice , Joshua S. Dillon , Adrian Liu , Jacqueline Hewitt

Soliton self-frequency shifts (SSFS) can be suppressed in optical fibers through spectral recoil, but this process leads to losses through continuous transfer of energy to a dispersive wave. We demonstrate a novel way to alter the strength…

Observations of the extragalactic radio background have uncovered a significant isotropic emission across multiple frequencies spanning from 22 MHz to 10 GHz. The intensity of this non-thermal emission component significantly exceeds the…

High Energy Astrophysical Phenomena · Physics 2016-07-05 Ke Fang , Tim Linden

We present the results of observations of the radio emission from Supernova 2001gd in NGC 5033 from 2002 February 8 through 2006 September 25. The data were obtained using the Very Large Array at wavelengths of 1.3 cm (22.4 GHz), 2 cm (14.9…

We have used the WGA catalog of ROSAT PSPC X-ray sources to study the X-ray spectrum of about 500 quasars in the redshift interval 0.1--4.1, detected with a signal to noise better than 7. We have parameterized the PSPC spectrum in terms of…

Astrophysics · Physics 2009-10-30 Fabrizio Fiore , Martin Elvis , Paolo Giommi , Paolo Padovani

Contemporary high-resolution sonar systems use broadband pulses and long arrays to achieve high resolution. It is important to understand effects that high-resolution sonar systems might have on quantitative measures of the scattered field…

Computational Physics · Physics 2021-06-11 Derek R. Olson , Anthony P. Lyons

In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS)…

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