Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/35134
Title: | Mining Mini-Halos with MeerKAT I. Calibration and Imaging | Authors: | Trehaeven, K. S. Parekh, V. Oozeer, N. Hugo, B. Smirnov, O. BERNARDI, Gianni Knowles,K. Tasse, C. Asad, K. M. B. Giacintucci, S. |
Issue Date: | 2023 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 520 | Issue: | 3 | First Page: | 4410 | Abstract: | Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this paper, we use third generation calibration (3GC), also called direction-dependent (DD) calibration, and point source subtraction on MeerKAT extragalactic continuum data. We calibrate and image archival MeerKAT L-band observations of a sample of five galaxy clusters (ACO 1413, ACO 1795, ACO 3444, MACS J1115.8+0129, MACS J2140.2-2339). We use the CARACal pipeline for direction-independent (DI) calibration, DDFacet and killMS for 3GC, followed by visibility-plane point source subtraction to image the underlying mini-halo without bias from any embedded sources. Our 3GC process shows a drastic improvement in artefact removal, to the extent that the local noise around severely affected sources was halved and ultimately resulted in a 7\% improvement in global image noise. Thereafter, using these spectrally deconvolved Stokes I continuum images, we directly measure for four mini-halos the flux density, radio power, size and in-band integrated spectra. Further to that, we show the in-band spectral index maps of the mini-halo (with point sources). We present a new mini-halo detection hosted by MACS J2140.2-2339, having flux density $S_{\rm 1.28\,GHz} = 2.61 \pm 0.31$ mJy, average diameter 296 kpc and $\alpha^{\rm 1.5\,GHz}_{\rm 1\,GHz} = 1.21 \pm 0.36$. We also found a $\sim$100 kpc southern extension to the ACO 3444 mini-halo which was not detected in previous VLA L-band observations. Our description of MeerKAT wide-field, wide-band data reduction will be instructive for conducting further mini-halo science. | URI: | http://hdl.handle.net/20.500.12386/35134 | URL: | https://academic.oup.com/mnras/article/520/3/4410/7025957 http://arxiv.org/abs/2303.08427v1 |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stad391 | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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trehaeven23.pdf | PDF editoriale | 3.05 MB | Adobe PDF | View/Open |
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