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Radio pulsars exhibit an enormous diversity of single pulse behaviour that involves sudden changes in pulsation mode and nulling occurring on timescales of tens or hundreds of spin periods. The pulsations appear both chaotic and…

High Energy Astrophysical Phenomena · Physics 2021-10-22 J. Dyks

We present 10 micron, ISO-SWS and Australia Telescope Compact Array observations of the region in the cluster Wd1 in Ara centred on the B[e] star Ara C. An ISO-SWS spectrum reveals emission from highly ionised species in the vicinity of the…

In the last three decades, about 50 radio supernovae have been detected as a result of targeted searches of optically discovered supernovae in the local universe. Despite this relatively small number some diversity among them has already…

High Energy Astrophysical Phenomena · Physics 2014-01-08 Atish Kamble , Alicia Soderberg , Edo Berger , Ashley Zauderer , Sayan Chakraborti , Peter Williams

We observed four nearby spiral galaxies (NGC 3627, NGC 4254, NGC 4736 and NGC 5055) in the K band with the 64-m Sardinia Radio Telescope, with the aim of detecting the Anomalous Microwave Emission (AME), a radiation component presumably due…

Extreme Scattering Events are radio-wave lensing events caused by AU-sized concentrations of ionised gas. Although they were discovered more than a decade ago we still have no clear picture of the physical nature of the lenses. To…

Astrophysics · Physics 2007-05-23 Mark A. Walker

We present a catalogue of a large sample of extended radio sources in the SCORPIO field, observed and resolved by the Australia Telescope Compact Array. SCORPIO, a pathfinder project for addressing the early operations of the Australia SKA…

Analysis of Giant Metrewave Radio Telescope low frequency data for an X-shaped source, 3C 223.1 has revealed an unusual result as discussed earlier by Lal & Rao (2004, MNRAS in press). The radio morphologies of it at 240 and 610 MHz show a…

Astrophysics · Physics 2007-05-23 Dharam Vir Lal , A. Pramesh Rao

Important informations on the origin and the propagation mechanisms of cosmic rays may be provided by the measurement of the anisotropies of their arrival direction. In this paper the observation of anisotropy regions at different angular…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Roberto Iuppa

Fast radio bursts (FRBs) are millisecond-timescale bursts of coherent radio emission that are luminous enough to be detectable at cosmological distances. In this review I describe the discovery of FRBs, subsequent advances in our…

High Energy Astrophysical Phenomena · Physics 2022-11-14 Matthew Bailes

We study the geometric effects of our galaxy's peculiar motion on the circles-in-the-sky. We show that the shape of these circles-in-the-sky remains circular, as detected by a local observer with arbitrary peculiar velocity. Explicit…

Astrophysics · Physics 2009-11-10 M. O. Calvao , G. I. Gomero , B. Mota , M. J. Reboucas

We present new sensitive, high angular resolution 1.3, 2, and 6 cm observations of the continuum emission from the peculiar emission-line star MWC 349A, made with the Very Large Array. This radio emission is believed to originate in an…

Astrophysics · Physics 2011-02-11 Luis F. Rodriguez , Y. Gomez , D. Tafoya

It is currently accepted that intrinsically compact and bright radio sources characterized by a convex spectrum peaking at frequencies ranging from 100 MHz to a few GHz are young objects. Following the evolutionary models, these objects…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-02 M. Orienti , D. Dallacasa

The Evolutionary Map of the Universe (EMU) large-area radio continuum survey will detect tens of millions of radio galaxies, giving an opportunity for the detection of previously unknown classes of objects. To maximise the scientific value…

From an on-going survey of the Galactic bulge, we have discovered a number of compact, steep spectrum radio sources. In this present study we have carried out more detailed observations for two of these sources, located 43 arcmin and 12.7…

High Energy Astrophysical Phenomena · Physics 2021-07-21 S. D. Hyman , D. A. Frail , J. S. Deneva , N. E. Kassim , S. Giacintucci , J. E. Kooi , T. J. W. Lazio , I. Joyner , W. M. Peters , V. Gajjar , A. P. V. Siemion

Since 2013, dense and narrow rings are known around the small Centaur object Chariklo and the dwarf planet Haumea. Dense material has also been detected around the Centaur Chiron, although its nature is debated. This is the first time ever…

Earth and Planetary Astrophysics · Physics 2020-01-22 Bruno Sicardy , Stefan Renner , Rodrigo Leiva , Françoise Roques , Maryame El Moutamid , Pablo Santos-Sanz , Josselin Desmars

We report the discovery of a transient radio source 2.7 arcsec (0.1 pc projected distance) South of the Galactic Center massive black hole, Sagittarius A*. The source flared with a peak of at least 80 mJy in March 2004. The source was…

Giant Radio Galaxies (GRGs) are Active Galactic Nuclei (AGN) with radio emission that extends over projected sizes $>0.7\,$Mpc. The large angular sizes associated with GRGs complicate their identification in radio survey images using…

Astrophysics of Galaxies · Physics 2023-11-16 Soren Ramdhanie , Yjan A. Gordon , Heinz Andernach , Eric J. Hooper , Brianna Sampson

Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide new insights to understand the evolution of galaxies,…

Astrophysics of Galaxies · Physics 2017-09-18 Ray P Norris

Fast radio bursts are extragalactic, sub-millisecond radio impulses of unknown origin [1,2]. Their dispersion measures, which quantify the observed frequency-dependent dispersive delays in terms of free-electron column densities,…

High Energy Astrophysical Phenomena · Physics 2019-07-16 Vikram Ravi

We examine the possibility that circles in the cosmic microwave background could be formed by the interaction of a gravitational wave pulse emitted in some pre-big-bang phase of the universe with the last scattering surface. We derive the…

General Relativity and Quantum Cosmology · Physics 2011-09-08 William Nelson , Edward Wilson-Ewing