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Recent low-frequency radio observations at 140 MHz discovered a 3 Mpc-long bridge of diffuse emission connecting the galaxy clusters Abell 0399 and Abell 0401. We present follow-up observations at 60 MHz to constrain the spectral index of…

We present a low frequency study of the diffuse radio emission in the galaxy cluster A754. We present new 150 MHz image of the galaxy cluster A754 made with the Giant Metrewave Radio Telescope (GMRT) and discuss the detection of 4 diffuse…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-24 Ruta Kale , K. S. Dwarakanath

We present and evaluate the prospects for detecting coherent radio counterparts to gravitational wave (GW) events using Murchison Widefield Array (MWA) triggered observations. The MWA rapid-response system, combined with its buffering mode…

We have detected 27 new supernova remnants (SNRs) using a new data release of the GLEAM survey from the Murchison Widefield Array (MWA) telescope, including the lowest surface-brightness SNR ever detected, G0.1-9.7. Our method uses spectral…

The Murchison Widefield Array (MWA), located in Western Australia, is one of the low-frequency precursors of the international Square Kilometre Array (SKA) project. In addition to pursuing its own ambitious science program, it is also a…

The number of active and non active satellites in Earth orbit has dramatically increased in recent decades, requiring the development of novel surveillance techniques to monitor and track them. In this paper, we build upon previous…

Instrumentation and Methods for Astrophysics · Physics 2020-04-01 Steve Prabu , Paul J Hancock , Xiang Zhang , Steven J Tingay

We have previously presented the results of a 325 MHz radio survey of M31, conducted with the A-configuration of the Very Large Array. In this survey, a total of 405 radio sources between <6" and 170" in extent were mapped with a resolution…

Astrophysics · Physics 2009-11-11 Joseph D. Gelfand , T. J. W. Lazio , B. M. Gaensler

The GMRT Radio Halo Survey, carried out at 610 MHz to investigate the statistical properties of cluster radio halos in a complete cluster sample selected in the redshift interval z=0.2-0.4, has significantly improved our understanding of…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-18 T. Venturi , S. Giacintucci , R. Cassano , G. Brunetti , D. Dallacasa , G. Macario , G. Setti , S. Bardelli , R. Athreya

Galaxy clusters undergo mergers that can generate extended radio sources called radio relics. Radio relics are the consequence of merger-induced shocks that propagate in the intra cluster medium (ICM). In this paper we analyse the radio,…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 F. de Gasperin , H. T. Intema , J. Ridl , M. Salvato , R. van Weeren , A. Bonafede , J. Greiner , R. Cassano , M. Bruggen

LWA1 is a new radio telescope operating in the frequency range 10-88 MHz, located in central New Mexico. The telescope consists of 258 pairs of dipole-type antennas whose outputs are individually digitized and formed into beams.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 S. W. Ellingson , G. B. Taylor , J. Craig , J. Hartman , J. Dowell , C. N. Wolfe , T. E. Clarke , B. C. Hicks , N. E. Kassim , P. S. Ray , L. J. Rickard , F. K. Schinzel , K. W. Weiler

Electron density irregularities in the ionosphere are known to be magnetically anisotropic, preferentially elongated along the lines of force. While many studies of their morphology have been undertaken by topside sounding and whistler…

We report on the design, deployment, and first results from a scintillation detector deployed at the Murchison Radio-astronomy Observatory (MRO). The detector is a prototype for a larger array -- the Square Kilometre Array Particle Array…

The presence of a radio halo in the massive, merging cluster Abell 3667 has recently become a focus of debate in the literature following a putative halo detection at 2.4 GHz despite a lack of detection at a range of lower frequencies…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-16 M. Johnston-Hollitt , L. Pratley

We report the design and functionality of the Murchison Widefield Array Particle Detector Array (MWA PDA), an array of eight particle scintillation detectors deployed to Inyarrimanha Ilgari Bundara, the Murchison Radio-astronomy Observatory…

Simulated maps of the HI distribution in the post-reionization era are used to study the prospects for detection with existing and upcoming radio telescopes. We consider detection in the redshifted radiation from the hyperfine transition…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-29 Nishikanta Khandai , Kanan K. Datta , J. S. Bagla

We present here results from observations at 5.5 and 9 GHz of the Bullet cluster 1E 0657-55.8 with the Australia Telescope Compact Array (ATCA). Our results show detection of diffuse emission in the cluster. Our findings are consistent with…

High Energy Astrophysical Phenomena · Physics 2016-07-13 Siddharth Malu , Abhirup Datta , Pritpal Sandhu

The remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$\,deg$^2$ sub-region of the…

Some galaxy clusters contain non-thermal synchrotron emitting plasma permeating the intracluster medium (ICM). The spectral properties of this radio emission are not well characterized at decameter wavelengths ({\nu} < 30 MHz), primarily…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-10 C. Groeneveld , R. J. van Weeren , A. Botteon , R. Cassano , F. de Gasperin , E. Osinga , G. Brunetti , H. J. A. Röttgering

We present original GMRT radio observations of the galaxy cluster Abell~725, at a redshift of 0.09, along with other archival observations. Our GMRT maps reveal two steep-spectrum diffuse filaments in the cluster, along with a previously…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 M. B. Pandge , Ruta Kale , Pratik Dabhade , Mousumi Mahato , Somak Raychaudhury