Mining mini-halos with MeerKAT I. Calibration and imaging

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dc.contributor.authorTrehaeven, K. S.
dc.contributor.authorParekh, Viral
dc.contributor.authorAsad, Khan M.B.
dc.date.accessioned2023-05-30T12:04:46Z
dc.date.available2023-05-30T12:04:46Z
dc.date.issued2023
dc.description.abstractRadio 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 directiondependent (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 per cent 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 S1.28 GHz = 2.61 ± 0.31 mJy, average diameter 296 kpc, and α1.5 GHz 1 GHz = 1.21 ± 0.36. We also found a ∼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.en_US
dc.identifier.citationTrehaeven, K. S. et al. (2023). Mining mini-halos with MeerKAT I. Calibration and imaging. Monthly Notices of the Royal Astronomical Society, 520(3), 4410-4426. 10.1093/mnras/stad391en_US
dc.identifier.issn1365-2966
dc.identifier.uri10.1093/mnras/stad391
dc.identifier.urihttp://hdl.handle.net/10566/8965
dc.language.isoenen_US
dc.publisherOxford University Pressen_US
dc.subjectAstronomyen_US
dc.subjectPhysicsen_US
dc.subjectGalaxiesen_US
dc.subjectRdio continuumen_US
dc.subjectSouth Africaen_US
dc.titleMining mini-halos with MeerKAT I. Calibration and imagingen_US
dc.typeArticleen_US

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