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1. A Spectropolarimetric Study of Pictor A Radio Galaxy with MeerKAT

Author

Andati, Lexy A. L., Baidoo, Lerato M., Ramaila, Athanaseus J. T., Smirnov, Oleg M., Makhathini, Sphesihle, and Perley, Richard A.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of a polarimetric study from our new high-sensitivity L-band (0.8--1.7 GHz) observation of Pictor A with the MeerKAT radio telescope. We confirm the presence of the radio jet extending from the nucleus to the western hotspot of this source. Additionally, we show the radio emission expected to be coincident with previously observed X-ray emission in the radio lobes, confirming that the emission mechanism is of inverse Compton origin, as suggested by a previous study. Our spectropolarimetric analysis using the RM-Synthesis technique reveals a relatively uniform mean RM distribution across the lobes of Pictor A, with most lines-of-sight exhibiting single-peaked Faraday spectra. However, a number of the lines-of-sight exhibit single peaked spectra with a wide base or multiple peaks, suggesting the presence of multiple Faraday components or a Faraday thick structure along Pictor A's lines-of-sight. We also confirm the asymmetry in RM variability and depolarization between the two lobes of this source which were reported in a previous study., Comment: 15 pages,15 figures. This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer review. The version of record [Andati L.A.L. et al., 2024] is available online at: https://doi.org/10.1093/mnras/stae598

Published
2024
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2. The SARAO MeerKAT 1.3 GHz Galactic Plane Survey

Author

Goedhart, S., Cotton, W. D., Camilo, F., Thompson, M. A., Umana, G., Bietenholz, M., Woudt, P. A., Anderson, L. D., Bordiu, C., Buckley, D. A. H., Buemi, C. S., Bufano, F., Cavallaro, F., Chen, H., Chibueze, J. O., Egbo, D., Frank, B. S., Hoare, M. G., Ingallinera, A., Irabor, T., Kraan-Korteweg, R. C., Kurapati, S., Leto, P., Loru, S., Mutale, M., Obonyo, W. O., Plavin, A., Rajohnson, S. H. A., Rigby, A., Riggi, S., Seidu, M., Serra, P., Smart, B. M., Stappers, B. W., Steyn, N., Surnis, M., Trigilio, C., Williams, G. M., Abbott, T. D., Adam, R. M., Asad, K. M. B., Baloyi, T., Bauermeister, E. F., Bennet, T. G. H., Bester, H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., Cloete, K., de Villiers, M. S., de Villiers, D. I. L., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., Fourie, D. J., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, L. M. G., Hugo, B. V., Isaacson, A. I., Józsa, G. I. G., Jonas, J. L., Jordaan, J. D. B. L., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Lord, R. T., Macfarlane, P. S., Magnus, L. G., Magozore, C., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Maruping, P., McAlpine, K., Merry, B. C., Mgodeli, M., Millenaar, R. P., Mokone, O. J., Monama, T. E., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Nicolson, G. D., Ockards, M. T., Oozeer, N., Passmoor, S. S., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ratcliffe, S. M., Renil, R., Richter, L. L., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O. M., Tiplady, A. J., van Balla, T. J., van der Byl, A., Van Tonder, V., Venter, A. J., Venter, M., Welz, M. G., and Williams, L. P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251\deg $\le l \le$ 358\deg and 2\deg $\le l \le$ 61\deg at $|b| \le 1.5\deg $). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of $\sim$10--20 $\mu$ Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance., Comment: Accepted for publication in MNRAS. The data release is live and links can be found in the Data Availability Statement in the paper

Published
2023

3. The extended HI halo of NGC 4945 as seen by MeerKAT

Author

Ianjamasimanana, Roger, Koribalski, B. S., Józsa, Gyula I. G., Kamphuis, Peter, de Blok, W. J. G., Kleiner, Dane, Namumba, Brenda, Carignan, Claude, Dettmar, Ralf-Jürgen, Serra, Paolo, Smirnov, Oleg M., Thorat, Kshitij, Hugo, Benjamin V., Ramaila, Athanaseus J. T., Maina, Eric, Maccagni, Filippo M., Makhathini, Sphesihle, Andati, Lexy A. L., Molnár, Dániel Cs., Perkins, Simon, Loi, Francesca, Ramatsoku, Mpati, and Atemkeng, Marcellin

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Observations of the neutral atomic hydrogen (HI) in the nuclear starburst galaxy NGC 4945 with MeerKAT are presented. We find a large amount of halo gas, previously missed by HI observations, accounting for 6.8% of the total HI mass. This is most likely gas blown into the halo by star formation. Our maps go down to a $3\sigma$ column density level of $5\times10^{18} cm^{-2}$ . We model the HI distribution using tilted-ring fitting techniques and find a warp on the galaxy's approaching and receding sides. The HI in the northern side of the galaxy appears to be suppressed. This may be the result of ionisation by the starburst activity in the galaxy, as suggested by a previous study. The origin of the warp is unclear but could be due to past interactions or ram pressure stripping. Broad, asymmetric HI absorption lines extending beyond the HI emission velocity channels are present towards the nuclear region of NGC 4945. Such broad lines suggest the existence of a nuclear ring moving at a high circular velocity. This is supported by the clear rotation patterns in the HI absorption velocity field. The asymmetry of the absorption spectra can be caused by outflows or inflows of gas in the nuclear region of NGC 4945. The continuum map shows small extensions on both sides of the galaxy's major axis that might be signs of outflows resulting from the starburst activity., Comment: 20 pages, 15 figures, 3 tables, accepted for publication in MNRAS

Published
2022
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4. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

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

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

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 magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total intensity and spectral index mosaics of the region from 20 pointings (144 hours on-target in total), covering 6.5 square degrees with an angular resolution of 4$"$,at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT's high sensitivity, exceptional $u,v$-plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new non-thermal filament complexes, and enhanced views of the Radio Arc Bubble, Sgr A and Sgr B regions. This project is a SARAO public legacy survey, and the image products are made available with this article., Comment: 29 pages, 15 figures, 3 tables, accepted for publication in the The Astrophysical Journal. Replacement arXiv version with higher quality figures

Published
2022
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5. The detection of a massive chain of dark HI clouds in the GAMA G23 Field

Author

Jozsa, Gyula I. G., Jarrett, T. H., Cluver, Michelle, Wong, O. Ivy, Havenga, Okkert, Yao, H. F. M., Marchetti, L., Taylor, E. N., Kamphuis, Peter, Maccagni, Filippo M., Ramaila, Athanaseus J. T., Serra, Paolo, Smirnov, Oleg M., White, Sarah V., Kilborn, Virginia, Holwerda, B. W., Hopkins, A. M., Brough, S., Pimbblet, K. A., Driver, Simon P., and Kuijken, K.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We report on the detection of a large, extended HI cloud complex in the GAMA G23 field, located at a redshift of $z\,\sim\,0.03$, observed as part of the MeerHOGS campaign (a pilot survey to explore the mosaicing capabilities of MeerKAT). The cloud complex, with a total mass of $10^{10.0}\,M_\odot$, lies in proximity to a large galaxy group with $M_\mathrm{dyn}\sim10^{13.5}\,M_\odot$. We identify seven HI peak concentrations, interconnected as a tenuous 'chain' structure, extending $\sim 400\,\mathrm{kpc}$ from east-to-west, with the largest (central) concentration containing $10{^{9.7}}\,M_\odot$ in HI gas distributed across $50\,\mathrm{kpc}$. The main source is not detected in ultra-violet, optical or infrared imaging. The implied gas mass-to-light ($M_\mathrm{HI}$/$L_\mathrm{r}$) is extreme ($>$1000) even in comparison to other 'dark clouds'. The complex has very little kinematic structure ($110\,\mathrm{km}\,\mathrm{s}^{-1}$), making it difficult to identify cloud rotation. Assuming pressure support, the total mass of the central concentration is $>10^{10.2}\,M_\odot$, while a lower limit to the dynamical mass in the case of full rotational support is $10^{10.4}\,M_\odot$. If the central concentration is a stable structure, it has to contain some amount of unseen matter, but potentially less than is observed for a typical galaxy. It is, however, not clear whether the structure has any gravitationally stable concentrations. We report a faint UV--optical--infrared source in proximity to one of the smaller concentrations in the gas complex, leading to a possible stellar association. The system nature and origins is enigmatic, potentially being the result of an interaction with or within the galaxy group it appears to be associated with., Comment: 25 pages, 10 figures, accepted for publication in ApJ, minor corrections

Published
2021
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6. The MeerKAT Galaxy Cluster Legacy Survey I. Survey Overview and Highlights

Author

Knowles, K., Cotton, W. D., Rudnick, L., Camilo, F., Goedhart, S., Deane, R., Ramatsoku, M., Bietenholz, M. F., Brüggen, M., Button, C., Chen, H., Chibueze, J. O., Clarke, T. E., de Gasperin, F., Ianjamasimanana, R., Józsa, G. I. G., Hilton, M., Kesebonye, K. C., Kolokythas, K., Kraan-Korteweg, R. C., Lawrie, G., Lochner, M., Loubser, S. I., Marchegiani, P., Mhlahlo, N., Moodley, K., Murphy, E., Namumba, B., Oozeer, N., Parekh, V., Pillay, D. S., Passmoor, S. S., Ramaila, A. J. T., Ranchod, S., Retana-Montenegro, E., Sebokolodi, L., Sikhosana, S. P., Smirnov, O., Thorat, K., Venturi, T., Abbott, T. D., Adam, R. M., Adams, G., Aldera, M. A., Bauermeister, E. F., Bennett, T. G. H., Bode, W. A., Botha, D. H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., de Villiers, D. I. L., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., Foley, A. R., Fourie, D. J., Frank, B. S., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hlakola, M. J., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, J. M. G., Hugo, B. V., Isaacson, A. R., Jonas, J. L., Jordaan, J. D. B., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kotze, A. G., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Liebenberg, D., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Makhaba, A., Makhathini, S., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Mauch, T., McAlpine, K., Merry, B. C., Millenaar, R. P., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramanujam, N. M., Ramudzuli, Z. R., Ratcliffe, S. M., Renil, R., Robyntjies, A., Rust, A. N., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M., Sofeya, L., Taljaard, B., Tasse, C., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., van Dyk, C. L., Van Tonder, V., Van Wyk, R., Venter, A. J., Venter, M., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The MeerKAT Galaxy Cluster Legacy Survey (MGCLS) is a programme of long-track MeerKAT L-band (900-1670 MHz) observations of 115 galaxy clusters, observed for $\sim$6-10 hours each in full polarisation. The first legacy product data release (DR1), made available with this paper, includes the MeerKAT visibilities, basic image cubes at $\sim$8" resolution, and enhanced spectral and polarisation image cubes at $\sim$8" and 15" resolutions. Typical sensitivities for the full-resolution MGCLS image products are $\sim$3-5 {\mu}Jy/beam. The basic cubes are full-field and span 4 deg^2. The enhanced products consist of the inner 1.44 deg^2 field of view, corrected for the primary beam. The survey is fully sensitive to structures up to $\sim$10' scales and the wide bandwidth allows spectral and Faraday rotation mapping. HI mapping at 209 kHz resolution can be done at $0

Published
2021
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7. Anomalous gas in ESO 149-G003: A MeerKAT-16 View

Author

Józsa, Gyula I. G., Thorat, Kshitij, Kamphuis, Peter, Sebokolodi, Lerato, Maina, Eric K., Wang, Jing, Pieterse, Daniëlle L. A., Groot, Paul, Ramaila, Athanaseus J. T., Serra, Paolo, Andati, Lexy A. L., de Blok, W. J. G., Hugo, Benjamin V., Kleiner, Dane, Maccagni, Filippo M., Makhathini, Sphesihle, Molnár, Dániel Cs., Ramatsoku, Mpati, Smirnov, Oleg M., Bloemen, Steven, Paterson, Kerry, Vreeswijk, Paul, McBride, Vanessa, Klein-Wolt, Marc, Woudt, Patrick, Körding, Elmar, Poole, Rudolf Le, Goedhart, Sharmila, Passmoor, Sean S., Serylak, Maciej, and Dettmar, Ralf-Jürgen

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

ESO 149-G003 is a close-by, isolated dwarf irregular galaxy. Previous observations with the ATCA indicated the presence of anomalous neutral hydrogen (HI) deviating from the kinematics of a regularly rotating disc. We conducted follow-up observations with the MeerKAT radio telescope during the 16-dish Early Science programme as well as with the MeerLICHT optical telescope. Our more sensitive radio observations confirm the presence of anomalous gas in ESO 149-G003, and further confirm the formerly tentative detection of an extraplanar HI component in the galaxy. Employing a simple tilted-ring model, in which the kinematics is determined with only four parameters but including morphological asymmetries, we reproduce the galaxy's morphology, which shows a high degree of asymmetry. By comparing our model with the observed HI, we find that in our model we cannot account for a significant (but not dominant) fraction of the gas. From the differences between our model and the observed data cube we estimate that at least 7%-8% of the HI in the galaxy exhibits anomalous kinematics, while we estimate a minimum mass fraction of less than 1% for the morphologically confirmed extraplanar component. We investigate a number of global scaling relations and find that, besides being gas-dominated with a neutral gas-to-stellar mass ratio of 1.7, the galaxy does not show any obvious global peculiarities. Given its isolation, as confirmed by optical observations, we conclude that the galaxy is likely currently acquiring neutral gas. It is either re-accreting gas expelled from the galaxy or accreting pristine intergalactic material., Comment: 16 pages, 14 figures, MNRAS, Accepted 2020 December 2, in original form 2019 September 18

Published
2020
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8. MeerKAT HI commissioning observations of MHONGOOSE galaxy ESO 302-G014

Author

de Blok, W. J. G., Athanassoula, E., Bosma, A., Combes, F., English, J., Heald, G. H., Kamphuis, P., Koribalski, B. S., Meurer, G. R., Román, J., Sardone, A., Verdes-Montenegro, L., Bigiel, F., Brinks, E., Chemin, L., Fraternali, F., Jarrett, T., Kleiner, D., Maccagni, F. M., Pisano, D. J., Serra, P., Spekkens, K., Amram, P., Carignan, C., Dettmar, R-J., Gibson, B. K., Holwerda, B. W., Józsa, G. I. G, Lucero, D. M., Oosterloo, T. A., Ramaila, A. J. T., Ramatsoku, M., Sheth, K., Walter, F., Wong, O. I., Zijlstra, A. A., Bloemen, S., Groot, P. J., Poole, R. Le, Klein-Wolt, M., Körding, E. G., McBride, V. A., Paterson, K., Pieterse, D. L. A., Vreeswijk, P., and Woudt, P. A.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of three commissioning HI observations obtained with the MeerKAT radio telescope. These observations make up part of the preparation for the forthcoming MHONGOOSE nearby galaxy survey, which is a MeerKAT large survey project that will study the accretion of gas in galaxies and the link between gas and star formation. We used the available HI data sets, along with ancillary data at other wavelengths, to study the morphology of the MHONGOOSE sample galaxy, ESO 302-G014, which is a nearby gas-rich dwarf galaxy. We find that ESO 302-G014 has a lopsided, asymmetric outer disc with a low column density. In addition, we find a tail or filament of HI clouds extending away from the galaxy, as well as an isolated HI cloud some 20 kpc to the south of the galaxy. We suggest that these features indicate a minor interaction with a low-mass galaxy. Optical imaging shows a possible dwarf galaxy near the tail, but based on the current data, we cannot confirm any association with ESO 302-G014. Nonetheless, an interaction scenario with some kind of low-mass companion is still supported by the presence of a significant amount of molecular gas, which is almost equal to the stellar mass, and a number of prominent stellar clusters, which suggest recently triggered star formation. These data show that MeerKAT produces exquisite imaging data. The forthcoming full-depth survey observations of ESO 302-G014 and other sample galaxies will, therefore, offer insights into the fate of neutral gas as it moves from the intergalactic medium onto galaxies., Comment: Accepted for publication in Astronomy and Astrophysics

Published
2020
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9. MeerKAT-16 HI observation of the dIrr galaxy WLM

Author

Ianjamasimanana, Roger, Namumba, Brenda, Ramaila, Athanaseus J. T., Saburova, Anna S., Jozsa, Gyula I. G., Myburgh, Talon, Thorat, Kshitij, Carignan, Claude, Maina, Eric, de Blok, W. J. G., Andati, Lexy A. L., Hugo, Benjamin V., Kleiner, Dane, Kamphuis, Peter, Serra, Paolo, Smirnov, Oleg M., Maccagni, Filippo M., Makhathini, Sphesihle, Molnar, Daniel Cs., Perkins, Simon, Ramatsoku, Mpati, and White, Sarah V.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present observations and models of the kinematics and the distribution of the neutral hydrogen (HI) in the isolated dwarf irregular galaxy, Wolf-Lundmark-Melotte (WLM). We observed WLM with the Green Bank Telescope (GBT) and as part of the MeerKAT Early Science Programme, where 16 dishes were available. The HI disc of WLM extends out to a major axis diameter of 30 arcmin (8.5 kpc), and a minor axis diameter of 20 arcmin (5.6 kpc) as measured by the GBT. We use the MeerKAT data to model WLM using the TiRiFiC software suite, allowing us to fit different tilted-ring models and select the one that best matches the observation. Our final best-fitting model is a flat disc with a vertical thickness, a constant inclination and dispersion, and a radially-varying surface brightness with harmonic distortions. To simulate bar-like motions, we include second-order harmonic distortions in velocity in the tangential and the vertical directions. We present a model with only circular motions included and a model with non-circular motions. The latter describes the data better. Overall, the models reproduce the global distribution and the kinematics of the gas, except for some faint emission at the 2-sigma level. We model the mass distribution of WLM with a pseudo-isothermal (ISO) and a Navarro-Frenk-White (NFW) dark matter halo models. The NFW and the ISO models fit the derived rotation curves within the formal errors, but with the ISO model giving better reduced chi-square values. The mass distribution in WLM is dominated by dark matter at all radii., Comment: Accepted for publication in MNRAS, 25 pages, 21 figures, 5 tables

Published
2020
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10. GASP XXVI. HI Gas in Jellyfish Galaxies: The case of JO201 and JO206

Author

Ramatsoku, M., Serra, P., Poggianti, B. M., Moretti, A., Gullieuszik, M., Bettoni, D., Deb, T., Franchetto, A., van Gorkom, J. H., Jaffé, Y., Tonnesen, S., Verheijen, M. A. W, Vulcani, B., Andati, L. A. L., de Blok, E., Józsa, G. I. G., Kamphuis, P., Kleiner, D., Maccagni, F. M., Makhathini, S., Molnár, D. Cs., Ramaila, A. J. T., Smirnov, O., and Thorat, K.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present HI observations of the jellyfish galaxy, JO201. This massive galaxy (M$_{\ast} = 3.5 \times 10^{10}$ M$_\odot$) is falling along the line-of-sight towards the centre of a rich cluster (M$_{200} \sim 1.6 \times 10^{15}$ M$_\odot$, $\sigma_{cl} \sim 982$ km/s) at a high velocity $\geq$3363 km/s. Its H$\alpha$ emission shows a $\sim$40 kpc tail confined closely to its stellar disc and a $\sim$100 kpc tail extending further out. We find HI emission coinciding only with the shorter clumpy H$\alpha$ tail. In total, we measure an HI mass of M$_{\rm HI} = 1.65 \times 10^{9}$ M$_\odot$, which is about 60% lower than expected based on its stellar mass and stellar surface density. We compared JO201 to another jellyfish in the GASP sample, JO206 (of similar mass but residing in a 10$\times$ less massive cluster), and find that they are similarly HI-deficient. Of the total HI mass in JO201, about 30% lies outside the galaxy disc in projection. This HI fraction is probably a lower limit since most of the HI is redshifted relative to the stellar disc and could be outside the disc. The global star formation rate (SFR) analysis of JO201 suggests that its observed SFR would be expected if it had 10$\times$ its current HI mass. The disc is the main contributor of the high star formation efficiency at a given HI gas density for both galaxies, but their tails also show higher star formation efficiencies compared to the outer regions of field galaxies. Generally, we find that JO201 and JO206 are similar based on their HI content, stellar mass and star formation rate. This finding is unexpected considering their different environments. A toy model comparing the ram pressure of the ICM versus the restoring forces of these galaxies suggests that the ram pressure strength exerted on them could be comparable if we consider their 3D orbital velocities and radial distances relative to the clusters., Comment: 9 pages, 8 figures, Accepted for publication in A&A

Published
2020
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11. MeerKATHI -- an end-to-end data reduction pipeline for MeerKAT and other radio telescopes

Author

Józsa, Gyula I. G., White, Sarah V., Thorat, Kshitij, Smirnov, Oleg M., Serra, Paolo, Ramatsoku, Mpati, Ramaila, Athanaseus J. T., Perkins, Simon J., Molnár, Dániel Cs., Makhathini, Sphesihle, Maccagni, Filippo M., Kleiner, Dane, Kamphuis, Peter, Hugo, Benjamin V., de Blok, W. J. G., and Andati, Lexy A. L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

MeerKATHI is the current development name for a radio-interferometric data reduction pipeline, assembled by an international collaboration. We create a publicly available end-to-end continuum- and line imaging pipeline for MeerKAT and other radio telescopes. We implement advanced techniques that are suitable for producing high-dynamic-range continuum images and spectroscopic data cubes. Using containerization, our pipeline is platform-independent. Furthermore, we are applying a standardized approach for using a number of different of advanced software suites, partly developed within our group. We aim to use distributed computing approaches throughout our pipeline to enable the user to reduce larger data sets like those provided by radio telescopes such as MeerKAT. The pipeline also delivers a set of imaging quality metrics that give the user the opportunity to efficiently assess the data quality., Comment: 4 pages, 1 figure, in conference proceedings of the ADASS XXIX, to appear in ASPC. CARACal (formerly MeerKATHI) can be accessed at: https://caracal.readthedocs.io

Published
2020

12. Collimated synchrotron threads linking the radio lobes of ESO137-006

Author

Ramatsoku, M., Murgia, M., Vacca, V., Serra, P., Makhathini, S., Govoni, F., Smirnov, O., Andati, L. A. L., de Blok, E., Józsa, G. I. G., Kamphuis, P., Kleiner, D., Maccagni, F. M., Molnár, D. Cs., Ramaila, A. J. T., Thorat, K., and White, S. V.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present MeerKAT 1000 MHz and 1400 MHz observations of a bright radio galaxy in the southern hemisphere, ESO~137-006. The galaxy lies at the centre of the massive and merging Norma galaxy cluster. The MeerKAT continuum images (rms ~0.02 mJy/beam at ~10" resolution) reveal new features that have never been seen in a radio galaxy before: collimated synchrotron threads of yet unknown origin, which link the extended and bent radio lobes of ESO~137-006. The most prominent of these threads stretches in projection for about 80 kpc and is about 1 kpc in width. The radio spectrum of the threads is steep, with a spectral index of up to $\alpha\simeq 2$ between 1000 MHz and 1400 MHz., Comment: 5 pages, 4 figures, accepted for publication in A&A letters

Published
2020
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13. The 1.28 GHz MeerKAT DEEP2 Image

Author

Mauch, T., Cotton, W. D., Condon, J. J., Matthews, A. M., Abbott, T. D., Adam, R. M., Aldera, M. A., Asad, K. M. B., Bauermeister, E. F., Bennett, T. G. H., Bester, H., Botha, D. H., Brederode, L. R. S., Brits, Z. B., Buchner, S. J., Burger, J. P., Camilo, F., Chalmers, J. M., Cheetham, T., de Villiers, D., de Villiers, M. S., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., February, S., Frank, B. S., Gamatham, R. R. G., Geyer, M., Goedhart, S., Gounden, S., Gumede, S. C., Heywood, I., Hlakola, M. J., Horrell, J. M. G., Hugo, B., Isaacson, A. R., Józsa, G. I. G., Jonas, J. L., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kriek, N., Kriel, H., Kusel, T. W., Lehmensiek, R., Loots, A., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Martens, A., Merry, B., Millenaar, R., Mnyandu, N., Moeng, I. P. T., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T. O., Oozeer, N., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ramudzuli, Z. R., Renil, R., Richter, L. L., Robyntjies, A., Salie, S., Schollar, C. T. G., Schwardt, L. C., Serylak, M., Siebrits, R., Sirothia, S. K., Smirnov, O. M., Sofeya, L., Stone, G., Taljaard, B., Tasse, C., Theron, I. P., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., Van Tonder, V., Wallace, B. H., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one $\approx 68'$ FWHM primary beam area with $7.6''$ FWHM resolution and $0.55 \pm 0.01$ $\mu$Jy/beam rms noise. Its J2000 center position $\alpha=04^h 13^m 26.4^s$, $\delta=-80^\circ 00' 00''$ was selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary beam attenuation pattern, estimate telescope pointing errors, and pinpoint $(u,v)$ coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion $P(D)$ distribution from $0.25$ to $10$ $\mu$Jy with counts of individual DEEP2 sources between $10$ $\mu$Jy and $2.5$ mJy. Most sources fainter than $S \sim 100$ $\mu$Jy are distant star-forming galaxies obeying the FIR/radio correlation, and sources stronger than $0.25$ $\mu$Jy account for $\sim93\%$ of the radio background produced by star-forming galaxies. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson (2014) model for the evolution of star-forming galaxies based on UV and infrared data underpredicts our 1.4 GHz source count in the range $-5 \lesssim \log[S(\mathrm{Jy})] \lesssim -4$., Comment: 20 pages, 18 figures. Accepted for publication in ApJ

Published
2019
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14. Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

Camilo, F., Scholz, P., Serylak, M., Buchner, S., Merryfield, M., Kaspi, V. M., Archibald, R. F., Bailes, M., Jameson, A., van Straten, W., Sarkissian, J., Reynolds, J. E., Johnston, S., Hobbs, G., Abbott, T. D., Adam, R. M., Adams, G. B., Alberts, T., Andreas, R., Asad, K. M. B., Baker, D. E., Baloyi, T., Bauermeister, E. F., Baxana, T., Bennett, T. G. H., Bernardi, G., Booisen, D., Booth, R. S., Botha, D. H., Boyana, L., Brederode, L. R. S., Burger, J. P., Cheetham, T., Conradie, J., Conradie, J. P., Davidson, D. B., de Bruin, G., de Swardt, B., de Villiers, C., de Villiers, D. I. L., de Villiers, M. S., de Villiers, W., de Waal, C., Dikgale, M. A., Toit, G. du, Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B., Fataar, S., Foley, A. R., Foster, G., Fourie, D., Gamatham, R., Gatsi, T., Geschke, R., Goedhart, S., Grobler, T. L., Gumede, S. C., Hlakola, M. J., Hokwana, A., Hoorn, D. H., Horn, D., Horrell, J., Hugo, B., Isaacson, A., Jacobs, O., van Rensburg, J. P. Jansen, Jonas, J. L., Jordaan, B., Joubert, A., Joubert, F., Jozsa, G. I. G., Julie, R., Julius, C. C., Kapp, F., Karastergiou, A., Karels, F., Kariseb, M., Karuppusamy, R., Kasper, V., Knox-Davies, E. C., Koch, D., Kotze, P. P. A., Krebs, A., Kriek, N., Kriel, H., Kusel, T., Lamoor, S., Lehmensiek, R., Liebenberg, D., Liebenberg, I., Lord, R. T., Lunsky, B., Mabombo, N., Macdonald, T., Macfarlane, P., Madisa, K., Mafhungo, L., Magnus, L. G., Magozore, C., Mahgoub, O., Main, J. P. L., Makhathini, S., Malan, J. A., Malgas, P., Manley, J. R., Manzini, M., Marais, L., Marais, N., Marais, S. J., Maree, M., Martens, A., Matshawule, S. D., Matthysen, N., Mauch, T., Nally, L. D. Mc, Merry, B., Millenaar, R. P., Mjikelo, C., Mkhabela, N., Mnyandu, N., Moeng, I. T., Mokone, O. J., Monama, T. E., Montshiwa, K., Moss, V., Mphego, M., New, W., Ngcebetsha, B., Ngoasheng, K., Niehaus, H., Ntuli, P., Nzama, A., Obies, F., Obrocka, M., Ockards, M. T., Olyn, C., Oozeer, N., Otto, A. J., Padayachee, Y., Passmoor, S., Patel, A. A., Paula, S., Peens-Hough, A., Pholoholo, B., Prozesky, P., Rakoma, S., Ramaila, A. J. T., Rammala, I., Ramudzuli, Z. R., Rasivhaga, M., Ratcliffe, S., Reader, H. C., Renil, R., Richter, L., Robyntjies, A., Rosekrans, D., Rust, A., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L., Seranyane, S., Sethosa, G., Sharpe, C., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O., Smith, S., Sofeya, L., Songqumase, N., Spann, R., Stappers, B., Steyn, D., Steyn, T. J., Strong, R., Struthers, A., Stuart, C., Sunnylall, P., Swart, P. S., Taljaard, B., Tasse, C., Taylor, G., Theron, I. P., Thondikulam, V., Thorat, K., Tiplady, A., Toruvanda, O., van Aardt, J., van Balla, T., Heever, L. van den, van der Byl, A., van der Merwe, C., van der Merwe, P., van Niekerk, P. C., van Rooyen, R., van Staden, J. P., van Tonder, V., van Wyk, R., Wait, I., Walker, A. L., Wallace, B., Welz, M., Williams, L. P., Xaia, B., Young, N., and Zitha, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation., Comment: Published in ApJ (2018 April 5); 13 pages, 4 figures

Published
2018
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16. A spectropolarimetric study of the radio galaxy Pictor A using MeerKAT.

Author

Andati, Lexy A L, Baidoo, Lerato M, Ramaila, Athanaseus J T, Smirnov, Oleg M, Makhathini, Sphesihle, and Perley, Richard A

Subjects
RADIO galaxies, MEERKAT, GALACTIC magnetic fields, RADIO telescopes, RADIO programs
Abstract

We present the results of a polarimetric study from our new high-sensitivity L -band (0.8–1.7 GHz) observation of Pictor A using the MeerKAT radio telescope. We confirm the presence of the radio jet extending from the nucleus to the western hotspot of this source. Additionally, we show the radio emission expected to coincide with previously observed X-ray emission in the radio lobes, confirming that the emission mechanism is of inverse Compton origin, as suggested by a previous study. Our spectropolarimetric analysis using the rotation measure synthesis technique reveals a relatively uniform mean rotation measure distribution across the lobes of Pictor A, with most lines of sight exhibiting single-peaked Faraday spectra. However, a number of the lines of sight exhibit single peaked spectra with a wide base or multiple peaks, suggesting the presence of multiple Faraday components or a Faraday thick structure along Pictor A's lines of sight. We also confirm the asymmetry in rotation measure variability and depolarization between the two lobes of this source, as reported in a previous study. [ABSTRACT FROM AUTHOR]

Published
2024
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18. The extended H i halo of NGC 4945 as seen by MeerKAT

Author

Ianjamasimanana, Roger, primary, Koribalski, B S, additional, Józsa, Gyula I G, additional, Kamphuis, Peter, additional, de Blok, W J G, additional, Kleiner, Dane, additional, Namumba, Brenda, additional, Carignan, Claude, additional, Dettmar, Ralf-Jürgen, additional, Serra, Paolo, additional, Smirnov, Oleg M, additional, Thorat, Kshitij, additional, Hugo, Benjamin V, additional, Ramaila, Athanaseus J T, additional, Maina, Eric, additional, Maccagni, Filippo M, additional, Makhathini, Sphesihle, additional, Andati, Lexy A L, additional, Molnár, Dániel Cs, additional, Perkins, Simon, additional, Loi, Francesca, additional, Ramatsoku, Mpati, additional, and Atemkeng, Marcellin, additional

Published
2022
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19. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

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

Published
2022
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20. The Detection of a Massive Chain of Dark H i Clouds in the GAMA G23 Field

Author

Józsa, G. I. G., primary, Jarrett, T. H., additional, Cluver, M. E., additional, Wong, O. I., additional, Havenga, O., additional, Yao, H. F. M., additional, Marchetti, L., additional, Taylor, E. N., additional, Kamphuis, P., additional, Maccagni, F. M., additional, Ramaila, A. J. T., additional, Serra, P., additional, Smirnov, O. M., additional, White, S. V., additional, Kilborn, V., additional, Holwerda, B. W., additional, Hopkins, A. M., additional, Brough, S., additional, Pimbblet, K. A., additional, Driver, S. P., additional, and Kuijken, K., additional

Published
2022
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21. The MeerKAT Galaxy Cluster Legacy Survey

Author

Knowles, K., primary, Cotton, W. D., additional, Rudnick, L., additional, Camilo, F., additional, Goedhart, S., additional, Deane, R., additional, Ramatsoku, M., additional, Bietenholz, M. F., additional, Brüggen, M., additional, Button, C., additional, Chen, H., additional, Chibueze, J. O., additional, Clarke, T. E., additional, de Gasperin, F., additional, Ianjamasimanana, R., additional, Józsa, G. I. G., additional, Hilton, M., additional, Kesebonye, K. C., additional, Kolokythas, K., additional, Kraan-Korteweg, R. C., additional, Lawrie, G., additional, Lochner, M., additional, Loubser, S. I., additional, Marchegiani, P., additional, Mhlahlo, N., additional, Moodley, K., additional, Murphy, E., additional, Namumba, B., additional, Oozeer, N., additional, Parekh, V., additional, Pillay, D. S., additional, Passmoor, S. S., additional, Ramaila, A. J. T., additional, Ranchod, S., additional, Retana-Montenegro, E., additional, Sebokolodi, L., additional, Sikhosana, S. P., additional, Smirnov, O., additional, Thorat, K., additional, Venturi, T., additional, Abbott, T. D., additional, Adam, R. M., additional, Adams, G., additional, Aldera, M. A., additional, Bauermeister, E. F., additional, Bennett, T. G. H., additional, Bode, W. A., additional, Botha, D. H., additional, Botha, A. G., additional, Brederode, L. R. S., additional, Buchner, S., additional, Burger, J. P., additional, Cheetham, T., additional, de Villiers, D. I. L., additional, Dikgale-Mahlakoana, M. A., additional, du Toit, L. J., additional, Esterhuyse, S. W. P., additional, Fadana, G., additional, Fanaroff, B. L., additional, Fataar, S., additional, Foley, A. R., additional, Fourie, D. J., additional, Frank, B. S., additional, Gamatham, R. R. G., additional, Gatsi, T. G., additional, Geyer, M., additional, Gouws, M., additional, Gumede, S. C., additional, Heywood, I., additional, Hlakola, M. J., additional, Hokwana, A., additional, Hoosen, S. W., additional, Horn, D. M., additional, Horrell, J. M. G., additional, Hugo, B. V., additional, Isaacson, A. R., additional, Jonas, J. L., additional, Jordaan, J. D. B., additional, Joubert, A. F., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kasper, V. A., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kotze, A. G., additional, Kriek, N., additional, Kriel, H., additional, Krishnan, V. K., additional, Kusel, T. W., additional, Legodi, L. S., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Lord, R. T., additional, Lunsky, B. M., additional, Madisa, K., additional, Magnus, L. G., additional, Main, J. P. L., additional, Makhaba, A., additional, Makhathini, S., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, S. J., additional, Maree, M. D. J., additional, Martens, A., additional, Mauch, T., additional, McAlpine, K., additional, Merry, B. C., additional, Millenaar, R. P., additional, Mokone, O. J., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Ngoasheng, K. J., additional, Ockards, M. T., additional, Otto, A. J., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ramanujam, N. M., additional, Ramudzuli, Z. R., additional, Ratcliffe, S. M., additional, Renil, R., additional, Robyntjies, A., additional, Rust, A. N., additional, Salie, S., additional, Sambu, N., additional, Schollar, C. T. G., additional, Schwardt, L. C., additional, Schwartz, R. L., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Slabber, M., additional, Sofeya, L., additional, Taljaard, B., additional, Tasse, C., additional, Tiplady, A. J., additional, Toruvanda, O., additional, Twum, S. N., additional, van Balla, T. J., additional, van der Byl, A., additional, van der Merwe, C., additional, van Dyk, C. L., additional, Van Tonder, V., additional, Van Wyk, R., additional, Venter, A. J., additional, Venter, M., additional, Welz, M. G., additional, Williams, L. P., additional, and Xaia, B., additional

Published
2022
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22. MeerKAT-64 discovers wide-spread tidal debris in the nearby NGC 7232 galaxy group

Author

Namumba, B, primary, Koribalski, B S, additional, Józsa, G I G, additional, Lee-Waddell, K, additional, Jones, M G, additional, Carignan, C, additional, Verdes-Montenegro, L, additional, Ianjamasimanana, R, additional, de Blok, W J G, additional, Cluver, M, additional, Garrido, J, additional, Sánchez-Expósito, S, additional, Ramaila, A J T, additional, Thorat, K, additional, Andati, L A L, additional, Hugo, B V, additional, Kleiner, D, additional, Kamphuis, P, additional, Serra, P, additional, Smirnov, O M, additional, Maccagni, F M, additional, Makhathini, S, additional, Molnár, D Cs, additional, Perkins, S, additional, Ramatsoku, M, additional, White, S V, additional, and Loi, F, additional

Published
2021
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23. MeerKATHI -- an end-to-end data reduction pipeline for MeerKAT and other radio telescopes

Author

J��zsa, Gyula I. G., White, Sarah V., Thorat, Kshitij, Smirnov, Oleg M., Serra, Paolo, Ramatsoku, Mpati, Ramaila, Athanaseus J. T., Perkins, Simon J., Moln��r, D��niel Cs., Makhathini, Sphesihle, Maccagni, Filippo M., Kleiner, Dane, Kamphuis, Peter, Hugo, Benjamin V., de Blok, W. J. G., and Andati, Lexy A. L.

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

MeerKATHI is the current development name for a radio-interferometric data reduction pipeline, assembled by an international collaboration. We create a publicly available end-to-end continuum- and line imaging pipeline for MeerKAT and other radio telescopes. We implement advanced techniques that are suitable for producing high-dynamic-range continuum images and spectroscopic data cubes. Using containerization, our pipeline is platform-independent. Furthermore, we are applying a standardized approach for using a number of different of advanced software suites, partly developed within our group. We aim to use distributed computing approaches throughout our pipeline to enable the user to reduce larger data sets like those provided by radio telescopes such as MeerKAT. The pipeline also delivers a set of imaging quality metrics that give the user the opportunity to efficiently assess the data quality., 4 pages, 1 figure, in conference proceedings of the ADASS XXIX, to appear in ASPC. CARACal (formerly MeerKATHI) can be accessed at: https://caracal.readthedocs.io

Published
2020

24. Anomalous gas in ESO 149-G003: a MeerKAT-16 view

Author

Józsa, Gyula I G, primary, Thorat, Kshitij, additional, Kamphuis, Peter, additional, Sebokolodi, Lerato, additional, Maina, Eric K, additional, Wang, Jing, additional, Pieterse, Daniëlle L A, additional, Groot, Paul, additional, Ramaila, Athanaseus J T, additional, Serra, Paolo, additional, Andati, Lexy A L, additional, de Blok, W J G, additional, Hugo, Benjamin V, additional, Kleiner, Dane, additional, Maccagni, Filippo M, additional, Makhathini, Sphesihle, additional, Molnár, Dániel Cs, additional, Ramatsoku, Mpati, additional, Smirnov, Oleg M, additional, Bloemen, Steven, additional, Paterson, Kerry, additional, Vreeswijk, Paul, additional, McBride, Vanessa, additional, Klein-Wolt, Marc, additional, Woudt, Patrick, additional, Körding, Elmar, additional, Le Poole, Rudolf, additional, Goedhart, Sharmila, additional, Passmoor, Sean S, additional, Serylak, Maciej, additional, and Dettmar, Ralf-Jürgen, additional

Published
2020
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25. MeerKAT HI commissioning observations of MHONGOOSE galaxy ESO 302-G014

Author

de Blok, W. J. G., primary, Athanassoula, E., additional, Bosma, A., additional, Combes, F., additional, English, J., additional, Heald, G. H., additional, Kamphuis, P., additional, Koribalski, B. S., additional, Meurer, G. R., additional, Román, J., additional, Sardone, A., additional, Verdes-Montenegro, L., additional, Bigiel, F., additional, Brinks, E., additional, Chemin, L., additional, Fraternali, F., additional, Jarrett, T., additional, Kleiner, D., additional, Maccagni, F. M., additional, Pisano, D. J., additional, Serra, P., additional, Spekkens, K., additional, Amram, P., additional, Carignan, C., additional, Dettmar, R.-J., additional, Gibson, B. K., additional, Holwerda, B. W., additional, Józsa, G. I. G., additional, Lucero, D. M., additional, Oosterloo, T. A., additional, Ramaila, A. J. T., additional, Ramatsoku, M., additional, Sheth, K., additional, Walter, F., additional, Wong, O. I., additional, Zijlstra, A. A., additional, Bloemen, S., additional, Groot, P. J., additional, Le Poole, R., additional, Klein-Wolt, M., additional, Körding, E. G., additional, McBride, V. A., additional, Paterson, K., additional, Pieterse, D. L. A., additional, Vreeswijk, P., additional, and Woudt, P. A., additional

Published
2020
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26. GASP

Author

Ramatsoku, M., primary, Serra, P., additional, Poggianti, B. M., additional, Moretti, A., additional, Gullieuszik, M., additional, Bettoni, D., additional, Deb, T., additional, Franchetto, A., additional, van Gorkom, J. H., additional, Jaffé, Y., additional, Tonnesen, S., additional, Verheijen, M. A. W., additional, Vulcani, B., additional, Andati, L. A. L., additional, de Blok, E., additional, Józsa, G. I. G., additional, Kamphuis, P., additional, Kleiner, D., additional, Maccagni, F. M., additional, Makhathini, S., additional, Molnár, D. Cs., additional, Ramaila, A. J. T., additional, Smirnov, O., additional, and Thorat, K., additional

Published
2020
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27. MeerKAT-16 H i observation of the dIrr galaxy WLM

Author

Ianjamasimanana, Roger, primary, Namumba, Brenda, additional, Ramaila, Athanaseus J T, additional, Saburova, Anna S, additional, Józsa, Gyula I G, additional, Myburgh, Talon, additional, Thorat, Kshitij, additional, Carignan, Claude, additional, Maina, Eric, additional, de Blok, W J G, additional, Andati, Lexy A L, additional, Hugo, Benjamin V, additional, Kleiner, Dane, additional, Kamphuis, Peter, additional, Serra, Paolo, additional, Smirnov, Oleg M, additional, Maccagni, Filippo M, additional, Makhathini, Sphesihle, additional, Molnár, Dániel Cs, additional, Perkins, Simon, additional, Ramatsoku, Mpati, additional, and White, Sarah V, additional

Published
2020
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28. Collimated synchrotron threads linking the radio lobes of ESO 137-006

Author

Ramatsoku, M., primary, Murgia, M., additional, Vacca, V., additional, Serra, P., additional, Makhathini, S., additional, Govoni, F., additional, Smirnov, O., additional, Andati, L. A. L., additional, de Blok, E., additional, Józsa, G. I. G., additional, Kamphuis, P., additional, Kleiner, D., additional, Maccagni, F. M., additional, Molnár, D. Cs., additional, Ramaila, A. J. T., additional, Thorat, K., additional, and White, S. V., additional

Published
2020
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29. The 1.28 GHz MeerKAT DEEP2 Image

Author

Mauch, T., primary, Cotton, W. D., additional, Condon, J. J., additional, Matthews, A. M., additional, Abbott, T. D., additional, Adam, R. M., additional, Aldera, M. A., additional, Asad, K. M. B., additional, Bauermeister, E. F., additional, Bennett, T. G. H., additional, Bester, H., additional, Botha, D. H., additional, Brederode, L. R. S., additional, Brits, Z. B., additional, Buchner, S. J., additional, Burger, J. P., additional, Camilo, F., additional, Chalmers, J. M., additional, Cheetham, T., additional, Villiers, D. de, additional, Villiers, M. S. de, additional, Dikgale-Mahlakoana, M. A., additional, Toit, L. J. du, additional, Esterhuyse, S. W. P., additional, Fadana, G., additional, Fanaroff, B. L., additional, Fataar, S., additional, February, S., additional, Frank, B. S., additional, Gamatham, R. R. G., additional, Geyer, M., additional, Goedhart, S., additional, Gounden, S., additional, Gumede, S. C., additional, Heywood, I., additional, Hlakola, M. J., additional, Horrell, J. M. G., additional, Hugo, B., additional, Isaacson, A. R., additional, Józsa, G. I. G., additional, Jonas, J. L., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kasper, V. A., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kriek, N., additional, Kriel, H., additional, Kusel, T. W., additional, Lehmensiek, R., additional, Loots, A., additional, Lord, R. T., additional, Lunsky, B. M., additional, Madisa, K., additional, Magnus, L. G., additional, Main, J. P. L., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, S. J., additional, Martens, A., additional, Merry, B., additional, Millenaar, R., additional, Mnyandu, N., additional, Moeng, I. P. T., additional, Mokone, O. J., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Ngoasheng, K. J., additional, Ockards, M. T. O., additional, Oozeer, N., additional, Otto, A. J., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ramaila, A. J. T., additional, Ramudzuli, Z. R., additional, Renil, R., additional, Richter, L. L., additional, Robyntjies, A., additional, Salie, S., additional, Schollar, C. T. G., additional, Schwardt, L. C., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Smirnov, O. M., additional, Sofeya, L., additional, Stone, G., additional, Taljaard, B., additional, Tasse, C., additional, Theron, I. P., additional, Tiplady, A. J., additional, Toruvanda, O., additional, Twum, S. N., additional, Balla, T. J. van, additional, Byl, A. van der, additional, Merwe, C. van der, additional, Tonder, V. Van, additional, Wallace, B. H., additional, Welz, M. G., additional, Williams, L. P., additional, and Xaia, B., additional

Published
2020
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30. Anomalous gas in ESO 149-G003: a MeerKAT-16 view.

Author

Józsa, Gyula I G, Thorat, Kshitij, Kamphuis, Peter, Sebokolodi, Lerato, Maina, Eric K, Wang, Jing, Pieterse, Daniëlle L A, Groot, Paul, Ramaila, Athanaseus J T, Serra, Paolo, Andati, Lexy A L, de Blok, W J G, Hugo, Benjamin V, Kleiner, Dane, Maccagni, Filippo M, Makhathini, Sphesihle, Molnár, Dániel Cs, Ramatsoku, Mpati, Smirnov, Oleg M, and Bloemen, Steven

Subjects
OPTICAL telescopes, RADIO telescopes, GASES, KINEMATICS, GALACTIC dynamics, DWARF galaxies
Abstract

ESO 149-G003 is a close-by, isolated dwarf irregular galaxy. Previous observations with the ATCA indicated the presence of anomalous neutral hydrogen (⁠|$\rm{H{\small I}}$|⁠) deviating from the kinematics of a regularly rotating disc. We conducted follow-up observations with the MeerKAT radio telescope during the 16-dish Early Science programme as well as with the MeerLICHT optical telescope. Our more sensitive radio observations confirm the presence of anomalous gas in ESO 149-G003, and further confirm the formerly tentative detection of an extraplanar |$\rm{H{\small I}}$| component in the galaxy. Employing a simple tilted-ring model, in which the kinematics is determined with only four parameters but including morphological asymmetries, we reproduce the galaxy's morphology, which shows a high degree of asymmetry. By comparing our model with the observed |$\rm{H{\small I}}$|⁠ , we find that in our model, we cannot account for a significant (but not dominant) fraction of the gas. From the differences between our model and the observed data cube, we estimate that at least 7–8 per cent of the |$\rm{H{\small I}}$| in the galaxy exhibits anomalous kinematics, while we estimate a minimum mass fraction of less than 1 per cent for the morphologically confirmed extraplanar component. We investigate a number of global scaling relations and find that, besides being gas-dominated with a neutral gas-to-stellar mass ratio of 1.7, the galaxy does not show any obvious global peculiarities. Given its isolation, as confirmed by optical observations, we conclude that the galaxy is likely currently acquiring neutral gas. It is either re-accreting gas expelled from the galaxy or accreting pristine intergalactic material. [ABSTRACT FROM AUTHOR]

Published
2021
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31. Revival of the Magnetar PSR J1622–4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

Camilo, F., primary, Scholz, P., additional, Serylak, M., additional, Buchner, S., additional, Merryfield, M., additional, Kaspi, V. M., additional, Archibald, R. F., additional, Bailes, M., additional, Jameson, A., additional, Straten, W. van, additional, Sarkissian, J., additional, Reynolds, J. E., additional, Johnston, S., additional, Hobbs, G., additional, Abbott, T. D., additional, Adam, R. M., additional, Adams, G. B., additional, Alberts, T., additional, Andreas, R., additional, Asad, K. M. B., additional, Baker, D. E., additional, Baloyi, T., additional, Bauermeister, E. F., additional, Baxana, T., additional, Bennett, T. G. H., additional, Bernardi, G., additional, Booisen, D., additional, Booth, R. S., additional, Botha, D. H., additional, Boyana, L., additional, Brederode, L. R. S., additional, Burger, J. P., additional, Cheetham, T., additional, Conradie, J., additional, Conradie, J. P., additional, Davidson, D. B., additional, Bruin, G. De, additional, Swardt, B. de, additional, Villiers, C. de, additional, Villiers, D. I. L. de, additional, Villiers, M. S. de, additional, Villiers, W. de, additional, Waal, C. De, additional, Dikgale, M. A., additional, Toit, G. du, additional, Toit, L. J. du, additional, Esterhuyse, S. W. P., additional, Fanaroff, B., additional, Fataar, S., additional, Foley, A. R., additional, Foster, G., additional, Fourie, D., additional, Gamatham, R., additional, Gatsi, T., additional, Geschke, R., additional, Goedhart, S., additional, Grobler, T. L., additional, Gumede, S. C., additional, Hlakola, M. J., additional, Hokwana, A., additional, Hoorn, D. H., additional, Horn, D., additional, Horrell, J., additional, Hugo, B., additional, Isaacson, A., additional, Jacobs, O., additional, van Rensburg, J. P. Jansen, additional, Jonas, J. L., additional, Jordaan, B., additional, Joubert, A., additional, Joubert, F., additional, Józsa, G. I. G., additional, Julie, R., additional, Julius, C. C., additional, Kapp, F., additional, Karastergiou, A., additional, Karels, F., additional, Kariseb, M., additional, Karuppusamy, R., additional, Kasper, V., additional, Knox-Davies, E. C., additional, Koch, D., additional, Kotzé, P. P. A., additional, Krebs, A., additional, Kriek, N., additional, Kriel, H., additional, Kusel, T., additional, Lamoor, S., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Liebenberg, I., additional, Lord, R. T., additional, Lunsky, B., additional, Mabombo, N., additional, Macdonald, T., additional, Macfarlane, P., additional, Madisa, K., additional, Mafhungo, L., additional, Magnus, L. G., additional, Magozore, C., additional, Mahgoub, O., additional, Main, J. P. L., additional, Makhathini, S., additional, Malan, J. A., additional, Malgas, P., additional, Manley, J. R., additional, Manzini, M., additional, Marais, L., additional, Marais, N., additional, Marais, S. J., additional, Maree, M., additional, Martens, A., additional, Matshawule, S. D., additional, Matthysen, N., additional, Mauch, T., additional, Nally, L. D. Mc, additional, Merry, B., additional, Millenaar, R. P., additional, Mjikelo, C., additional, Mkhabela, N., additional, Mnyandu, N., additional, Moeng, I. T., additional, Mokone, O. J., additional, Monama, T. E., additional, Montshiwa, K., additional, Moss, V., additional, Mphego, M., additional, New, W., additional, Ngcebetsha, B., additional, Ngoasheng, K., additional, Niehaus, H., additional, Ntuli, P., additional, Nzama, A., additional, Obies, F., additional, Obrocka, M., additional, Ockards, M. T., additional, Olyn, C., additional, Oozeer, N., additional, Otto, A. J., additional, Padayachee, Y., additional, Passmoor, S., additional, Patel, A. A., additional, Paula, S., additional, Peens-Hough, A., additional, Pholoholo, B., additional, Prozesky, P., additional, Rakoma, S., additional, Ramaila, A. J. T., additional, Rammala, I., additional, Ramudzuli, Z. R., additional, Rasivhaga, M., additional, Ratcliffe, S., additional, Reader, H. C., additional, Renil, R., additional, Richter, L., additional, Robyntjies, A., additional, Rosekrans, D., additional, Rust, A., additional, Salie, S., additional, Sambu, N., additional, Schollar, C. T. G., additional, Schwardt, L., additional, Seranyane, S., additional, Sethosa, G., additional, Sharpe, C., additional, Siebrits, R., additional, Sirothia, S. K., additional, Slabber, M. J., additional, Smirnov, O., additional, Smith, S., additional, Sofeya, L., additional, Songqumase, N., additional, Spann, R., additional, Stappers, B., additional, Steyn, D., additional, Steyn, T. J., additional, Strong, R., additional, Struthers, A., additional, Stuart, C., additional, Sunnylall, P., additional, Swart, P. S., additional, Taljaard, B., additional, Tasse, C., additional, Taylor, G., additional, Theron, I. P., additional, Thondikulam, V., additional, Thorat, K., additional, Tiplady, A., additional, Toruvanda, O., additional, Aardt, J. van, additional, Balla, T. van, additional, Heever, L. van den, additional, Byl, A. van der, additional, Merwe, C. van der, additional, Merwe, P. van der, additional, Niekerk, P. C. van, additional, Rooyen, R. van, additional, Staden, J. P. van, additional, Tonder, V. van, additional, Wyk, R. van, additional, Wait, I., additional, Walker, A. L., additional, Wallace, B., additional, Welz, M., additional, Williams, L. P., additional, Xaia, B., additional, Young, N., additional, and Zitha, S., additional

Published
2018
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32. GASP

Author

Ramatsoku, M., Serra, P., Poggianti, B. M., Moretti, A., Gullieuszik, M., Bettoni, D., Deb, T., Franchetto, A., van Gorkom, J. H., Jaffé, Y., Tonnesen, S., Verheijen, M. A. W., Vulcani, B., Andati, L. A. L., de Blok, E., Józsa, G. I. G., Kamphuis, P., Kleiner, D., Maccagni, F. M., Makhathini, S., Molnár, D. Cs., Ramaila, A. J. T., Smirnov, O., and Thorat, K.

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