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We report the discovery of large-scale diffuse radio emission South-East of the galaxy cluster MACS J0520.7-1328, detected through high sensitivity Giant Metrewave Radio Telescope 323 MHz observations. This emission is dominated by an…

Using the Sloan Digital Sky Survey (SDSS) and the FIRST (Faint Images of the Radio Sky at Twenty Centimeters) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Joshua D. Wing , Elizabeth L. Blanton

Over 2000 Gamma ray sources identified by the Large Area Telescope (LAT) on NASA's Fermi Gamma-ray Space Telescope are considered unassociated, meaning that they have no known counterparts in any other frequency regime. We have carried out…

We study the overdensity of point sources in the direction of X-ray-selected galaxy clusters from the Meta-Catalog of X-ray detected Clusters of galaxies (MCXC; $\langle z \rangle = 0.14$) at South Pole Telescope (SPT) and Sydney University…

Searches for continuous gravitational waves target nearly monochromatic gravitational wave emission from e.g. non-axysmmetric fast-spinning neutron stars. Broad surveys often require to explicitly search for a very large number of different…

General Relativity and Quantum Cosmology · Physics 2022-12-14 Benjamin Steltner , Thorben Menne , Maria Alessandra Papa , Heinz-Bernd Eggenstein

The new broad-band capabilities of large radio interferometers such as the GMRT and JVLA allow for long-integration mosaic imaging observations to create ultra-deep full-polarization images of the sky over wide frequency ranges. Achieving…

Astrophysics of Galaxies · Physics 2014-05-02 A. R. Taylor , S. Bhatnagar , J. Condon , D. A. Green , J. M. Stil , P. Jagannathan , N. Kantharia , R. Kothes , R. Perley , J. Wall , T. Willis

We outline the science case for extended radio emission and polarization in galaxy clusters which would be a scientifically important area of research for an upcoming Jansky Very Large Array Sky Survey. The survey would provide a major…

We present new, high frequency radio observations of the merging galaxy clusters PLCK G287.0+32.9, Abell 2744, and Bullet. These clusters are known to host $\sim$Mpc scale sources, known as radio halos, which are formed by the acceleration…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-20 K. Rajpurohit , A. Botteon , E. O'Sullivan , W. Forman , M. Balboni , L. Bruno , R. J. van Weeren , M. Hoeft , G. Brunetti , C. Jones , A. S. Rajpurohit , S. P. Sikhosana

We present the results of 325 MHz GMRT observations of a super-cluster field, known to contain five Abell clusters at redshift $z \sim 0.2$. We achieve a nominal sensitivity of $34\,\mu$Jy beam$^{-1}$ toward the phase centre. We compile a…

We report the discovery of a unique object in the MeerKAT Galaxy Cluster Legacy Survey (MGCLS) using the machine learning anomaly detection framework Astronomaly. This strange, ring-like source is 30' from the MGCLS field centred on Abell…

Astrophysics of Galaxies · Physics 2023-02-09 Michelle Lochner , Lawrence Rudnick , Ian Heywood , Kenda Knowles , Stanislav S. Shabala

Galaxy cluster velocity correlations and mass distributions are sensitive probes of cosmology and the growth of structure. Upcoming microwave surveys will enable extraction of velocities and temperatures from many individual clusters for…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-28 Avirukt Mittal , Francesco de Bernardis , Michael D. Niemack

The combination of galaxy clustering and weak lensing is a powerful probe of the cosmology model. We present a joint analysis of galaxy clustering and weak lensing cosmology using SDSS data as the tracer of dark matter (lens sample) and the…

Strong Lensing is a powerful probe of the matter distribution in galaxies and clusters and a relevant tool for cosmography. Analyses of strong gravitational lenses with Deep Learning have become a popular approach due to these astronomical…

We present a deep machine learning (ML) approach to constraining cosmological parameters with multi-wavelength observations of galaxy clusters. The ML approach has two components: an encoder that builds a compressed representation of each…

Instrumentation and Methods for Astrophysics · Physics 2022-02-16 Michelle Ntampaka , Alexey Vikhlinin

We outline here the next generation of cluster-finding algorithms. We show how advances in Computer Science and Statistics have helped develop robust, fast algorithms for finding clusters of galaxies in large multi-dimensional astronomical…

The environmental influence on the 1.4 GHz continuum radio emission of galaxies is analyzed in a 600 deg2 region of the local Universe containing the Shapley Supercluster (SSC). Galaxies in the FLASH and 6dFGS redshift surveys are…

Astrophysics · Physics 2012-02-21 Jean-Christophe Mauduit , Gary A. Mamon

A fraction of galaxy clusters host diffuse radio sources whose origins are investigated through multi-wavelength studies of cluster samples. We investigate the presence of diffuse radio emission in a sample of seven galaxy clusters in the…

This is the third in a series of papers that present observations and results for a sample of 76 ultra-steep-spectrum radio sources designed to find galaxies at high redshift. Here we present multi-frequency radio observations, from the…

Astrophysics · Physics 2009-11-11 I. J. Klamer , R. D. Ekers , J. J. Bryant , R. W. Hunstead , E. M. Sadler , C. De Breuck