MeerKAT follow-up of enigmatic GLEAM 4Jy sources Precious K. Sejake Collaborators: Sarah V White, Ian Heywood, Kshitij Thorat, Hertzog L Bester, Sphesihle Makhathini and Bernie Fanaroff ●Identiﬁed host galaxies for 98 sources, thanks to MeerKAT sensitivity and high resolution (~7“). ●MeerKAT images reveal various morphologies (i.e., compact ‘single’ morphology, typical symmetric lobes (i.e, ‘double’ and ‘triple’ morphology), head-tail, wide-angle tailed (WAT), X-shaped morphology and complex morphology). ●This work has illustrated the importance of a telescope's angular resolution and sensitivity for morphological classiﬁcation and host-galaxy cross-identiﬁcation of radio sources at low frequencies. The high-resolution images from MeerKAT has allowed us to resolve ambiguous host-galaxy identiﬁcations and enigmatic radio morphologies of the MeerKAT-2019 subset, evident in NVSS/SUMSS (45”) and/or TGSS (25”) images. Conclusion Active Galactic Nuclei (AGN) are compact luminous regions at the centre of their host galaxy. The emission from the AGN are thought to be driven by the accretion of material onto a SMBH at the centre and in some cases may result in the production of relativistic radio jets. AGN activity has been shown to signiﬁcantly impact the host galaxy by suppressing or promoting star formation; however, this is still a point of contention. Morganti et al. (2013) demonstrated that star formation might be suppressed whereby the radio jets expel gas from the system. Meanwhile, Croft et al. (2006) showed that the jets might trigger the collapse of the molecular gas and promote star formation. In order to gain a better understanding of which of these scenarios is more signiﬁcant, a large sample of AGN with powerful relativistic radio jets is needed to provide robust statistics on the features of these AGN. White et al., (2020a, 2020b) deﬁned such a sample, named the GLEAM 4-Jy (G4Jy) Sample. However, poor resolution archival data (at 25 to 45 arcsec - TGSS, NVSS/SUMSS) limited the host galaxy identiﬁcation of 140 G4Jy sources (which we refer to as the MeerKAT-2019 subset), as these sources had unclear, complex morphologies (see the ﬁgure on the left below). The primary aim of this work is to use the high-resolution images from MeerKAT (~7” resolution) to disentangle the morphology and identify the likely host galaxy of these sources. Introduction Method - Visual inspection Results ●The Square Kilometre Array (SKA)-Mid precursor telescope ●64 Antennas that are 13.5 m in diameter ●Maximum baseline of 8 km About 10% of the sources in the G4Jy Sample have a larger positional offset (|R.A.| > 10′′, |Dec.| > 10′′; sources outside the square cyan region), while What’s next? Obtain redshifts from SALT spectroscopic data MeerKAT Create and inspect overlays Determine the morphology Determine the host galaxy GLEAM (~2’ resolution, 200 MHz) NVSS (45” resolution, 1400 MHz, Dec > -40o), SUMSS (45” resolution, 843 MHz, Dec < -40o) TGSS (25” resolution, 150 MHz) MeerKAT (~7” resolution, 1300 MHz) WISE W1 band (3.4 µm) An overlay of G4Jy 917. The radio contours are from GLEAM, NVSS, TGSS, and new contours from MeerKAT, overlaid on the inverted greyscale WISE (3.4 μm) image. Shown in the bottom left corner is the beam size for each survey; GLEAM, NVSS, TGSS, and MeerKAT. The cyan hexagon indicates the brightness-weighted centroid position, the green crosses ‘x’ signs are the AllWISE positions within 3 arcmin from the centroid position, and the white ‘ + ’ sign is the AllWISE position for the corresponding host galaxy for this source. Clear structures seen in MeerKAT (~7 arcsec), not seen in TGSS (25 arcsec) and NVSS (45 arcsec) ●Sejake et al., (2023) (https://ui.adsabs.harvard.edu/abs/2023MNRAS.518.4290S/abstract) G4Jy 665 resolved into two unrelated sources An example of a G4Jy source with complex morphology at 25 to 45 “ the majority of the sources (57%) in the MeerKAT-2019 subset populate this outer region.We expect to have this larger po