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Related papers: Influence of synchrotron self-absorption on the 21…

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Recent theoretical developments for observing the Epoch of Reionization (EOR) have concentrated on the power spectrum signature of redshifted 21 cm emission. These studies have demonstrated the great potential of statistical EOR…

Astrophysics · Physics 2009-11-10 Miguel F. Morales

This study revisits the electroabsorption (EA) spectrum of polyacetylene, as functions of the electric field strength, isomerization degree, and light polarization states. The EA spectrum of $cis$-$(CH)_x$ reveals an oscillatory feature…

Other Condensed Matter · Physics 2024-05-07 Jaspal Singh Bola , Ryan M. Stolley , Prashanna Poudel , Joel S. Miller , Christoph Boheme , Z. Valy Vardeny

Understanding the impact of spectral coverage on parameter recovery is critical for accurate interpretation of blazar spectra. In this study, we examine how the data coverage influences the reliability of parameter estimation within the…

High Energy Astrophysical Phenomena · Physics 2025-11-26 N. Sahakyan , D. Bégué , P. Giommi , H. Dereli-Bégué , Asaf Pe'er

Spectral variability of radio sources encodes information about the conditions of intervening media, source structure, and emission processes. With new low-frequency radio interferometers observing over wide fractional bandwidths, studies…

Astrophysics of Galaxies · Physics 2020-12-23 K. Ross , J. R. Callingham , N. Hurley-Walker , N. Seymour , P. Hancock , T. M. O. Franzen , J. Morgan , S. V. White , M. E. Bell , P. Patil

We present Karl G. Jansky Very Large Array (VLA) S- (2--4 GHz), C- (4--8 GHz), and X-band (8--12 GHz) continuum observations toward seven radio-loud quasars at $z>5$. This sample has previously been found to exhibit spectral peaks at…

We investigate the connection between the turnover frequency in the radio spectrum, $\nu_{\rm TO}$, and the rate of ionising ultra-violet photons, $Q_{\rm HI}$, in extragalactic sources. From a large, optically selected, sample we find…

Astrophysics of Galaxies · Physics 2024-05-02 S. J. Curran

Observations of the HI 21cm transition line promises to be an important probe into the cosmic dark ages and epoch of reionization. One of the challenges for the detection of this signal is the accuracy of the foreground source removal. This…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 A. Datta , S. Bhatnagar , C. L. Carilli

Context. The repeating FRB121102 is so far the only extra-galactic Fast Radio Burst found to be associated with a counterpart, a steady radio source with a nearly flat spectral energy distribution (SED) in centimeter wavelengths. Aims.…

High Energy Astrophysical Phenomena · Physics 2021-12-01 L Resmi , J Vink , C H Ishwara-Chandra

Anomalous x-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are x-ray sources with unusual properties distinguishing them from both rotation-powered and most accretion-powered pulsars. Using archival ASCA data over the energy range…

Astrophysics · Physics 2009-11-06 D. Marsden , N. E. White

We present here an extension of our search for EISERS (Extremely Inverted Spectrum Extragalactic Radio Sources) to the northern hemisphere. With an inverted radio spectrum of slope $\alpha$ $>$ + 2.5, these rare sources would either require…

Astrophysics of Galaxies · Physics 2018-07-17 Mukul Mhaskey , Gopal-Krishna , Surajit Paul

We report the discovery and monitoring of radio emission from the Type Ic SN 2002ap ranging in frequency from 1.43 to 22.5 GHz, and in time from 4 to 50 days after the SN explosion. As in most other radio SNe, the radio spectrum of SN…

Astrophysics · Physics 2015-06-24 E. Berger , S. R. Kulkarni , R. A. Chevalier

Angular broadening observations of compact radio sources provide a powerful method for probing the solar corona and solar wind. Such observations enable studies of the phase structure function, turbulence amplitude, intermediate-scale…

Analyses of measurements of the distribution of absolute brightness temperature over the radio sky have led recently to suggestions that there exists a substantial unexplained extragalactic radio background. Consequently, there have been…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Ravi Subrahmanyan , Ramanath Cowsik

We present analytic approximations to the optically thin synchrotron and synchrotron self-Compton (SSC) spectra when Klein-Nishina (KN) effects are important and pair production and external radiation fields can be neglected. This theory is…

High Energy Astrophysical Phenomena · Physics 2009-10-02 Ehud Nakar , Shin'ichiro Ando , Re'em Sari

Low frequency observations at 330 and 74 MHz can provide new insights into supernova remnants (SNR). We can test theoretical predictions for spectral index variations. Nonlinear models of shock acceleration predict that the spectra from…

Astrophysics · Physics 2007-05-23 Kristy K. Dyer , Stephen P. Reynolds , Kazik J. Borkowski

Several experimental efforts are underway to measure the power spectrum of 21cm fluctuations from the Epoch of Reionization (EoR) using low-frequency radio interferometers. Experiments like the Hydrogen Epoch of Reionization Array (HERA)…

Instrumentation and Methods for Astrophysics · Physics 2019-06-19 Adam E. Lanman , Jonathan C. Pober

We present archival radio observations of SN1996cr from ATCA and MOST, and model its radio lightcurves using X-ray constrained hydrodynamical simulations of the interaction between the SN ejecta and the CSM. The early radio data show signs…

High Energy Astrophysical Phenomena · Physics 2015-06-15 C. Meunier , F. E. Bauer , V. V. Dwarkadas , B. Koribalski , B. Emonts , R. W. Hunstead , D. Campbell-Wilson , C. Stockdale , S. J. Tingay

We investigate different scenarios for the origin of the extragalactic radio background. The surface brightness of the background, as reported by the ARCADE 2 collaboration, is several times higher than that which would result from…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 J. Singal , L. Stawarz , A. Lawrence , V. Petrosian