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The use of continuum emission radio galaxies as cosmological tracers of the large-scale structure will soon move into a new phase. Upcoming surveys from the Australian Square Kilometre Array Pathfinder (ASKAP), MeerKAT, and the Square…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-28 Jacobo Asorey , David Parkinson

Modern radio telescope surveys, capable of detecting billions of galaxies in wide-field surveys, have made manual morphological classification impracticable. This applies in particular when the Square Kilometre Array Observatory (SKAO)…

Astrophysics of Galaxies · Physics 2026-01-09 Philipp Denzel , Manuel Weiss , Elena Gavagnin , Frank-Peter Schilling

Diffuse radio emission in galaxy clusters is a tracer of ultra-relativistic particles and $\mu$G-level magnetic fields, and is thought to be triggered by cluster merger events. In the distant Universe (i.e. $z>0.6$), such sources have been…

Gravitational waves (GWs) have rapidly become important cosmological probes since their first detection in 2015. As the number of detected events continues to rise, upcoming instruments like the Einstein Telescope (ET) and Cosmic Explorer…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-03 Stefano Zazzera , José Fonseca , Tessa Baker , Chris Clarkson

We present a catalog of galaxy clusters detected in a new ROSAT PSPC survey. The survey is optimized to sample, at high redshifts, the mass range corresponding to T> keV clusters at z=0. Technically, our survey is the extension of the 160…

Astrophysics · Physics 2009-11-11 R. A. Burenin , A. Vikhlinin , A. Hornstrup , H. Ebeling , H. Quintana , A. Mescheryakov

Context: Diffuse radio emission, in the form of radio halos and relics, traces regions in clusters with shocks or turbulence, probably produced by cluster mergers. Some models of diffuse radio emission in clusters indicate that virtually…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 R. J. van Weeren , H. J. A. Rottgering , M. Bruggen , A. Cohen

Community access to deep (i ~ 25), highly-multiplexed optical and near-infrared multi-object spectroscopy (MOS) on 8-40m telescopes would greatly improve measurements of cosmological parameters from LSST. The largest gain would come from…

To properly understand the evolution of high-redshift galaxy clusters, both passive and star-forming galaxies have to be considered. Here we study the clustering environment of 21 radio galaxies and quasars at 1<z<2.5 from the third…

Galaxies and clusters embedded in the large-scale structure of the Universe are observed to align in preferential directions. Galaxy alignment has been established as a potential probe for cosmological information, but the application of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Casper J. G. Vedder , Nora Elisa Chisari

We report on a search for steep spectrum radio sources within the 95% confidence error ellipses of the Fermi unassociated sources from the Large Array Telescope (LAT). Using existing catalogs and the newly released GMRT all-sky survey at…

High Energy Astrophysical Phenomena · Physics 2016-07-27 D. A. Frail , K. P. Mooley , P. Jagannathan , H. T. Intema

Faint $\gamma$-ray signatures emerge in Fermi-LAT data stacked scaled to the characteristic $R_{500}$ radii of MCXC galaxy clusters. This third paper in a series shows a $4.3\sigma$ excess of discrete 4FGL-DR4 catalog $\gamma$-ray sources…

High Energy Astrophysical Phenomena · Physics 2025-03-14 Uri Keshet

The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4 GHz) to a r.m.s. of 7 uJy per beam over an area of ~1 square degree centred on…

The inner $\sim$200 pc region of the Galaxy contains a 4 million M$_{\odot}$ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of…

Astrophysics of Galaxies · Physics 2022-02-09 I. Heywood , I. Rammala , F. Camilo , W. D. Cotton , F. Yusef-Zadeh , T. D. Abbott , R. M. Adam , G. Adams , M. A. Aldera , K. M. B. Asad , E. F. Bauermeister , T. G. H. Bennett , H. L. Bester , W. A. Bode , D. H. Botha , A. G. Botha , L. R. S. Brederode , S. Buchner , J. P. Burger , T. Cheetham , D. I. L. de Villiers , M. A. Dikgale-Mahlakoana , L. J. du Toit , S. W. P. Esterhuyse , B. L. Fanaroff , S. February , D. J. Fourie , B. S. Frank , R. R. G. Gamatham , M. Geyer , S. Goedhart , M. Gouws , S. C. Gumede , M. J. Hlakola , A. Hokwana , S. W. Hoosen , J. M. G. Horrell , B. Hugo , A. I. Isaacson , G. I. G. Józsa , J. L. Jonas , A. F. Joubert , R. P. M. Julie , F. B. Kapp , J. S. Kenyon , P. P. A. Kotzé , N. Kriek , H. Kriel , V. K. Krishnan , R. Lehmensiek , D. Liebenberg , R. T. Lord , B. M. Lunsky , K. Madisa , L. G. Magnus , O. Mahgoub , A. Makhaba , S. Makhathini , J. A. Malan , J. R. Manley , S. J. Marais , A. Martens , T. Mauch , B. C. Merry , R. P. Millenaar , N. Mnyandu , O. J. Mokone , T. E. Monama , M. C. Mphego , W. S. New , B. Ngcebetsha , K. J. Ngoasheng , M. T. Ockards , N. Oozeer , A. J. Otto , S. S. Passmoor , A. A. Patel , A. Peens-Hough , S. J. Perkins , A. J. T. Ramaila , N. M. R. Ramanujam , Z. R. Ramudzuli , S. M. Ratcliffe , A. Robyntjies , S. Salie , N. Sambu , C. T. G. Schollar , L. C. Schwardt , R. L. Schwartz , M. Serylak , R. Siebrits , S. K. Sirothia , M. Slabber , O. M. Smirnov , L. Sofeya , B. Taljaard , C. Tasse , A. J. Tiplady , O. Toruvanda , S. N. Twum , T. J. van Balla , A. van der Byl , C. van der Merwe , V. Van Tonder , R. Van Wyk , A. J. Venter , M. Venter , B. H. Wallace , M. G. Welz , L. P. Williams , B. Xaia

Wide-field, multi-band surveys now detect millions of unresolved sources in nearby galaxy clusters, yet separating globular clusters (GCs) from foreground stars and background galaxies remains challenging. Scalable, automated classification…

The clustering of galaxy clusters is a powerful cosmological tool, which can help to break degeneracies between parameters when combined with other cosmological observables. We aim to demonstrate its potential in constraining cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Alessandra Fumagalli , Matteo Costanzi , Alexandro Saro , Tiago Castro , Stefano Borgani

Modern radio telescopes will daily generate data sets on the scale of exabytes for systems like the Square Kilometre Array (SKA). Massive data sets are a source of unknown and rare astrophysical phenomena that lead to discoveries.…

Instrumentation and Methods for Astrophysics · Physics 2023-05-08 Steven Ndung'u , Trienko Grobler , Stefan J. Wijnholds , Dimka Karastoyanova , George Azzopardi

Models of radio galaxy physics have been primarily based on high frequency ($\geqslant$1 GHz) observations of their jets, hotspots, and lobes. Without highly resolved low frequency observations, which provide information on older plasma,…

Astrophysics of Galaxies · Physics 2023-02-15 V. H. Mahatma , A. Basu , M. J. Hardcastle , L. K. Morabito , R. J. van Weeren

Self-supervised learning (SSL) applied to natural images has demonstrated a remarkable ability to learn meaningful, low-dimension representations without labels, resulting in models that are adaptable to many different tasks. Until now,…

Machine learning techniques have been increasingly useful in astronomical applications over the last few years, for example in the morphological classification of galaxies. Convolutional neural networks have proven to be highly effective in…

Instrumentation and Methods for Astrophysics · Physics 2018-02-07 V. Lukic , M. Brüggen , J. K. Banfield , O. I. Wong , L. Rudnick , R. P. Norris , B. Simmons

Next generation radio telescopes will require orders of magnitude more computing power to provide a view of the universe with greater sensitivity. In the initial stages of the signal processing flow of a radio telescope, signal correlation…

Instrumentation and Methods for Astrophysics · Physics 2013-05-27 Ruonan Wang , Christopher Harris