ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline --
Early science observations from the Australian Square Kilometre Array Pathfinder (ASKAP) have revealed clear signals of diffuse radio emission associated with two clusters detected by the South Pole Telescope via their Sunyaev Zel'dovich signal. SPT CLJ0553-3342 (MACSJ0553.4-3342) and SPT CLJ06...
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ftdatacite:10.48550/arxiv.2006.01833 2023-05-15T18:23:15+02:00 ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- Wilber, Amanda G. Johnston-Hollitt, Melanie Duchesne, Stefan W. Tasse, Cyril Akamatsu, Hiroki Intema, Huib Hodgson, Torrance 2020 https://dx.doi.org/10.48550/arxiv.2006.01833 https://arxiv.org/abs/2006.01833 unknown arXiv arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Astrophysics of Galaxies astro-ph.GA Instrumentation and Methods for Astrophysics astro-ph.IM FOS Physical sciences Article CreativeWork article Preprint 2020 ftdatacite https://doi.org/10.48550/arxiv.2006.01833 2022-03-10T15:25:43Z Early science observations from the Australian Square Kilometre Array Pathfinder (ASKAP) have revealed clear signals of diffuse radio emission associated with two clusters detected by the South Pole Telescope via their Sunyaev Zel'dovich signal. SPT CLJ0553-3342 (MACSJ0553.4-3342) and SPT CLJ0638-5358 (Abell S0592) are both high-mass lensing clusters that have undergone major mergers. To improve the data products of these ASKAP early science observations and create science-fidelity images of the galaxy clusters, we performed direction-dependent (DD) calibration and imaging using state-of-the-art software {\sc killMS} and {\sc DDFacet}. We find that artefacts in the ASKAP images are greatly reduced after directional calibration. Here we present our DD calibrated ASKAP radio images of both clusters showing unambiguous giant radio halos with largest linear scales of $\sim1$~Mpc. The halo in MACSJ0553.4-3342 was previously detected with GMRT observations at 323 MHz, but appears more extended in our ASKAP image. Although there is a shock detected in the thermal X-ray emission of this cluster, we find that the particle number density in the shocked region is too low to allow for the generation of a radio shock. The radio halo in Abell S0592 is a new discovery, and the Southwest border of the halo coincides with a shock detected in X-rays. We discuss the origins of these halos considering both the hadronic and turbulent re-acceleration models as well as sources of \textit{seed} electrons. This work gives a positive indication of the potential of ASKAP's Evolutionary Map of the Universe (EMU) survey in detecting intracluster medium radio sources, and showcases the improvement in data products after utilising third-generation calibration techniques. : 19 pages, 8 figures, submitted to Publications of the Astronomical Society of Australia Article in Journal/Newspaper South pole DataCite Metadata Store (German National Library of Science and Technology) South Pole |
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DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
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language |
unknown |
topic |
Astrophysics of Galaxies astro-ph.GA Instrumentation and Methods for Astrophysics astro-ph.IM FOS Physical sciences |
spellingShingle |
Astrophysics of Galaxies astro-ph.GA Instrumentation and Methods for Astrophysics astro-ph.IM FOS Physical sciences Wilber, Amanda G. Johnston-Hollitt, Melanie Duchesne, Stefan W. Tasse, Cyril Akamatsu, Hiroki Intema, Huib Hodgson, Torrance ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
topic_facet |
Astrophysics of Galaxies astro-ph.GA Instrumentation and Methods for Astrophysics astro-ph.IM FOS Physical sciences |
description |
Early science observations from the Australian Square Kilometre Array Pathfinder (ASKAP) have revealed clear signals of diffuse radio emission associated with two clusters detected by the South Pole Telescope via their Sunyaev Zel'dovich signal. SPT CLJ0553-3342 (MACSJ0553.4-3342) and SPT CLJ0638-5358 (Abell S0592) are both high-mass lensing clusters that have undergone major mergers. To improve the data products of these ASKAP early science observations and create science-fidelity images of the galaxy clusters, we performed direction-dependent (DD) calibration and imaging using state-of-the-art software {\sc killMS} and {\sc DDFacet}. We find that artefacts in the ASKAP images are greatly reduced after directional calibration. Here we present our DD calibrated ASKAP radio images of both clusters showing unambiguous giant radio halos with largest linear scales of $\sim1$~Mpc. The halo in MACSJ0553.4-3342 was previously detected with GMRT observations at 323 MHz, but appears more extended in our ASKAP image. Although there is a shock detected in the thermal X-ray emission of this cluster, we find that the particle number density in the shocked region is too low to allow for the generation of a radio shock. The radio halo in Abell S0592 is a new discovery, and the Southwest border of the halo coincides with a shock detected in X-rays. We discuss the origins of these halos considering both the hadronic and turbulent re-acceleration models as well as sources of \textit{seed} electrons. This work gives a positive indication of the potential of ASKAP's Evolutionary Map of the Universe (EMU) survey in detecting intracluster medium radio sources, and showcases the improvement in data products after utilising third-generation calibration techniques. : 19 pages, 8 figures, submitted to Publications of the Astronomical Society of Australia |
format |
Article in Journal/Newspaper |
author |
Wilber, Amanda G. Johnston-Hollitt, Melanie Duchesne, Stefan W. Tasse, Cyril Akamatsu, Hiroki Intema, Huib Hodgson, Torrance |
author_facet |
Wilber, Amanda G. Johnston-Hollitt, Melanie Duchesne, Stefan W. Tasse, Cyril Akamatsu, Hiroki Intema, Huib Hodgson, Torrance |
author_sort |
Wilber, Amanda G. |
title |
ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
title_short |
ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
title_full |
ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
title_fullStr |
ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
title_full_unstemmed |
ASKAP reveals giant radio halos in two merging SPT galaxy clusters -- Making the case for a direction-dependent pipeline -- |
title_sort |
askap reveals giant radio halos in two merging spt galaxy clusters -- making the case for a direction-dependent pipeline -- |
publisher |
arXiv |
publishDate |
2020 |
url |
https://dx.doi.org/10.48550/arxiv.2006.01833 https://arxiv.org/abs/2006.01833 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.2006.01833 |
_version_ |
1766202803736281088 |